67 pubblicazioni classificate nel seguente modo:

Comparison of energy and environmental performance between warm and hot mix asphalt concrete production: A case study
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ferrotti, G.; Mancinelli, E.; Passerini, G.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/326971

Interlayer bonding properties of warm recycled asphalt pavements
EUROPEAN TRANSPORT/TRASPORTI EUROPEI
Autore/i: Ferrotti, G.; Ingrassia, L. P.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: The need for sustainable road infrastructures has led to great interest in Warm Mix Asphalt (WMA) technologies, which allow the production, lay-down and compaction of asphalt mixtures at reduced temperatures, about 40 degrees C lower than traditional Hot Mix Asphalt (HMA). The use of WMA ensures lower emissions and is also beneficial in the recycling of Reclaimed Asphalt (RA) deriving from the milling of end-of-life pavements. One of the main concerns regarding WMA is the possible poor adhesion between the pavement layers that could be caused by the reduced working temperatures during the paving operations. However, almost no data are currently available in literature on this aspect, which thus could represent a deterrent to the wide application of WMA by road agencies. In this regard, this paper focuses on the investigation of the interlayer bonding properties of warm recycled asphalt pavements constructed along various Italian motorways and national roads using different WMA chemical additives. The Interlayer Shear Strength (ISS) was measured at different pavement interfaces (wearing-binder, binder-base) and time intervals by testing extracted cores with ASTRA and Leutner equipment. The results show that the interlayer bonding properties of WMA pavements are comparable to HMA pavements and are not affected by the WMA additive type. Moreover, ISS depends on the properties of the tack coat applied between the layers and increases over time due to aging effects, especially when the interface is below an open-graded friction course (OGFC). These findings further encourage the use of WMA as environmentally sustainable technologies for the construction and maintenance of asphalt pavements.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/324951

Prediction of the Long-Term Performance of an Existing Warm Recycled Motorway Pavement
MATERIALS
Autore/i: Ingrassia, L. P.; Spadoni, S.; Ferrotti, G.; Virgili, A.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: Warm mix asphalt (WMA) technologies allow the production, lay-down and compaction of asphalt mixtures at reduced temperatures and the use of higher amounts of reclaimed asphalt pavement (RAP) with respect to conventional hot mix asphalt (HMA), leading to significant environmental benefits and energy savings. However, limited data is available on the long-term performance of such pavements. The objective of this study was to predict the long-term performance of an existing warm recycled motorway pavement (made with WMA mixtures containing RAP) constructed in 2016 in central Italy, along with the corresponding hot recycled pavement (made with HMA mixtures containing RAP). For this purpose, cores were taken from the pavements in 2022 to investigate the binder and base courses through dynamic modulus and cyclic fatigue tests, according to the simplified viscoelastic continuum damage (S-VECD) testing approach. The results of the tests were used to predict the service life of the pavements using two pieces of software, KENPAVE and FlexPAVE, based respectively on the elastic design method and the viscoelastic design method in the presence of damage. The FlexPAVE results indicated that the expected service life of the WMA pavement is much longer than that of the HMA pavement, mainly because the WMA mixtures have better damage properties than the HMA mixtures. Conversely, the KENPAVE simulations predicted a similar service life for the two pavements, highlighting the impossibility of the elastic method to catch the actual contribution of high-performance non-standard materials. The promising outcomes of the FlexPAVE simulations further encourage the application of warm recycled pavements.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/311529

Characterization of aged bitumen recovered from in-situ polymer-modified HMA and WMA using advanced technologies
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: D'Angelo, S.; Ferrotti, G.; Oliviero Rossi, C.; Caputo, P.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: The growing attention of public opinion towards the environment has prompted, in the last decades, to find eco- sustainable and economic alternatives to the traditional productions of hot-mix asphalt (HMA). Under these auspices, the use of warm mix asphalt (WMA) technology applied to mixtures containing reclaimed asphalt (RA) has grown, also due to the well-proven advantages in terms of plant odor emissions and improved working conditions. In addition, it is now known that the mechanical performance of WMAs is completely comparable, even superior in some cases, to that of HMAs. However, to date, there is no comparison in terms of long-term performance of bitumens used in full-scale pavements laid with the two different technologies. Therefore, the aim of this research is to evaluate the oxidative and rheological state of four bitumens recovered from different layers of a full-scale pavement prepared with WMA and HMA technologies and set up a methodology tool set for investigating the physicochemical properties of bitumens. An in-depth laboratory investigation, carried out through physicochemical and rheological tests, has shown that the bitumens used in WMA mixtures are char- acterized by less oxidation than HMA ones (which are characterized by longer relaxation and glass transition times) and the Styrene-Butadiene-Styrene (SBS) polymers inside them are less degraded and still contribute positively to the rheological response even after five years in service, demonstrating the ability of the chemical additive to act as possible “sacrificial agent”, safeguarding the rheological characteristics of polymer modified bitumens (PMBs).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/324952

Use of Modified Reclaimed Asphalt in Warm Mixtures
RILEM Bookseries
Autore/i: Ferrotti, G.; Canestrari, F.; Xiaotian, J.; Cardone, F.
Editore: Springer International Publishing
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Warm Mix Asphalt (WMA) has the advantage over conventional Hot Mix Asphalt (HMA) of reducing pollutant emissions and energy costs. The use of WMA technologies can be fruitfully coupled with the addition of Reclaimed Asphalt (RA) improving asphalt mixture performance. However, this aspect needs to be investigated in more detail. In this regard, this paper focused on the optimization and performance investigation of a dense graded modified asphalt mixture for wearing courses, produced with WMA technology and percentages of RA up to 25%. Two WMA mixtures with two contents of RA were prepared by using a chemical additive. The results were also compared with an HMA control mixture produced with a lower RA content. Shear gyratory compacted specimens were used for a series of laboratory tests to evaluate the performance. The study of stiffness, water sensitivity, permanent deformation and fracture characteristics pointed out that appropriately designed WMA mixtures with RA can be produced without penalizing the performance with respect to the control mixture.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295086

Asphalt Binder Modification with Plastomeric Compounds Containing Recycled Plastics and Graphene
MATERIALS
Autore/i: D’Angelo, S.; Ferrotti, G.; Cardone, F.; Canestrari, F
Classificazione: 1 Contributo su Rivista
Abstract: Polymer-modified bitumens are usually employed for enhancing the mixture performance against typical pavement distresses. This paper presents an experimental investigation of bitumens added with two plastomeric compounds, containing recycled plastics and graphene, typically used for asphalt concrete dry modification. The goal was to study the effects of the compounds on the rheological response of the binder phase, as well the adhesion properties, in comparison with a reference plain bitumen. The blends (combination of bitumen and compounds) were evaluated through dynamic viscosity tests, frequency sweep tests, and multiple stress creep recovery (MSCR) tests. Moreover, the bitumen bond strength (BBS) test was performed to investigate the behavior of the systems consisting of blends and aggregate substrates (virgin and pre-coated). The rheological tests indicated that both blends performed better than the plain bitumen, especially at high temperature, showing an enhanced rutting resistance. In terms of bond strength, comparable results were found between the blends and reference bitumen. Moreover, no performance differences were detected between the two types of blends
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295082

Interlayer bonding characterization of interfaces reinforced with geocomposites in field applications
GEOTEXTILES AND GEOMEMBRANES
Autore/i: Canestrari, F.; Cardone, F.; Gaudenzi, E.; Chiola, D.; Gasbarro, N.; Ferrotti, G.
Classificazione: 1 Contributo su Rivista
Abstract: Geocomposites are extensively used in asphalt pavements as they provide significant long-term pavement benefits. Indeed, when correctly installed, geocomposites enhance road pavement performance thanks to their waterproofing properties, stress absorbing membrane interlayer (SAMI) action and improved mechanical strength of the pavement. Nevertheless, the presence of an interlayer causes de-bonding effects that negatively influence the overall pavement characteristics. This paper presents an experimental investigation aimed at comparing the interlayer bonding characteristics of four different geocomposites with an unreinforced reference configuration, laid on an Italian motorway section, in which the reinforcement depth and the lower layer surface condition (milled or new) were also varied. Interlayer shear strength (ISS) was measured, on both cores and laboratory produced specimens, through Leutner and Ancona Shear Testing Research and Analysis (ASTRA) equipment. The ISS results showed that geocomposites can be successfully applied directly on milled surfaces. Moreover, the application of a normal stress, as in the ASTRA device, tends to mitigate any difference related to the specimen heterogeneity. Finally, existing laws, which correlate the results obtained with different shear equipment on unreinforced interfaces, were generalized by considering the presence of geocomposites and the corresponding ISS specification limits were proposed for both ASTRA and Leutner test.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295083

Asphalt mixture modification with a plastomeric compound containing recycled plastic: laboratory and field investigation
MATERIALS AND STRUCTURES
Autore/i: Cardone, Fabrizio; Spadoni, Sara; Ferrotti, Gilda; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The use of recycled plastic in asphalt pavements represents a sustainable and economic choice which, if correctly designed, could significantly improve the resistance against the typical distresses of flexible pavements. For this reason, this paper aims at evaluating the mechanical properties of two asphalt mixtures modified with two plastomeric compounds through the dry method, by comparing their results with those obtained for a reference asphalt mixture modified with Styrene–Butadiene–Styrene (SBS) polymers. One of the compounds consisted of plastomeric polymers, whereas the other was made of recycled plastic and graphene. The experimental program included laboratory tests on shear gyratory compacted specimens and cores extracted from a real-scale field trial. The results showed that stiffness, fatigue and rutting resistance of the two polymeric compound modified mixtures were comparable to those of the reference mixture. Finally, a Falling Weight Deflectometer (FWD) campaign, performed in the field after one year of service life of the pavement, showed a reduced structural response of the sections constructed with compound modified mixtures with respect to the reference one because of compaction issues and possible interlayer de-bonding effects.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/302700

Il Progetto di Ricerca “Warm Asphalt Recycling in Marche” (WARM 4.0)
RASSEGNA DEL BITUME
Autore/i: Canestrari, F.; Cardone, F.; Ferrotti, G.; Spada, A.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295115

Monitoring the evolution of the structural properties of warm recycled pavements with Falling Weight Deflectometer and laboratory tests
ROAD MATERIALS AND PAVEMENT DESIGN
Autore/i: Ingrassia, LORENZO PAOLO; Cardone, Fabrizio; Ferrotti, Gilda; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: In pavement engineering, the use of warm mix asphalt (WMA) technologies can ensure important environmental and technical benefits. However, several uncertainties about WMA still exist, such as long-term field performance and full compatibility with reclaimed asphalt pavement (RAP) or polymer modified bitumen (PMB). In this regard, a full-scale trial section (including three test fields with warm recycled mixtures prepared with different WMA chemical additives and a reference test field with hot recycled mixtures, all containing PMB) was constructed along an Italian motorway and monitored for several years of service life. The evolution of the structural properties was assessed with in-situ Falling Weight Deflectometer (FWD) tests and laboratory tests on extracted cores, both immediately after the construction of the trial section and after more than three years under actual traffic loading. It was found that the reduced working temperatures adopted for theWMAmixes (40°C lower than hot mix asphalt (HMA)) did not penalise the workability and the stiffness immediately after the trial section construction, whereas theHMAmixture experienced higher structural damage (likely due to more severe aging) during the in-service life. The WMA mixes exhibited better stiffness homogeneity and, overall, superior performance and potentially longer service life with respect to the referenceHMA mixture.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/290821

Performance Optimization of Warm Recycled Mixtures
Lecture Notes in Civil Engineering
Autore/i: Cardone, F.; Canestrari, F.; Jiang, X.; Ferrotti, G.
Editore: Springer
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Warm Mix Asphalt (WMA) technologies are becoming popular due to their ability to reduce mixing and compaction temperatures compared to the conventional hot mix asphalts (HMAs), with remarkable advantages of environment and costs. Moreover, WMA is considered as one of the most promising technology for increasing the re-use of Reclaimed Asphalt (RA) within the mixture although its effectiveness in recycling issues require more dedicated research activities. This paper describes a laboratory investigation aimed at optimizing a dense graded asphalt mixture for wearing course, produced with WMA technology and including up to 30% of RA. WMA mixtures were prepared by using two contents of a plain bitumen, two contents of RA and one chemical additive. A recycled HMA containing lower RA content, according to technical specifications currently applied in Italy, was selected as reference mixture. Strength and stiffness properties, water sensitivity, rutting and cracking resistance were investigated on shear gyratory compacted specimens. The result analysis on stiffness, rutting and fracture properties indicated the possibility to produce suitable WMA mixtures with higher RA contents without penalizing their performance compared to the reference one.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287658

Chemical, morphological and rheological characterization of bitumen partially replaced with wood bio-oil: Towards more sustainable materials in road pavements
JOURNAL OF TRAFFIC AND TRANSPORTATION ENGINEERING
Autore/i: Ingrassia, L. P.; Lu, X.; Ferrotti, G.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: Nowadays, sustainability and circular economy are two principles to be pursued in all fields. In road pavement engineering, they can be put into practice through the partial substitution of bitumen with industrial residues and by-products deriving from renewable materials. Within this framework, this paper presents an extensive investigation of the chemical, morphological and rheological properties of bio-binders obtained by mixing a conventional 50/70 bitumen with different percentages by weight (0, 5%, 10% and 15%) of a renewable bio-oil, generated as a residue in the processing of wood into pulp and paper. Results show that overall the bio-oil provides a softening effect, which, in terms of performance, leads to an improvement of the low-temperature behaviour and fatigue resistance with respect to the control bitumen, in spite of an increased tendency to permanent deformation. Although no chemical reaction appears to occur after blending, the peculiarities of the bio-oil affect the chemistry of the resulting bio-binders, whereas no phase separation is observed from the microscopic analysis. In addition, a Newtonian behaviour, an unchanged temperature susceptibility and a good fitting of 1S2P1D model to the rheological data are found, regardless of the bio-oil percentage considered. These promising outcomes suggest that such bio-binders can be favourably employed for several applications in road pavements.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276995

Investigating the “circular propensity” of road bio-binders: Effectiveness in hot recycling of reclaimed asphalt and recyclability potential
JOURNAL OF CLEANER PRODUCTION
Autore/i: Ingrassia, L. P.; Lu, X.; Ferrotti, G.; Conti, C.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: In pavement engineering, the use of bio-binders and reclaimed asphalt (RA) promotes the principles of sustainability and circular economy, without penalizing or even improving the performance. In this regard, this study focuses on the “circular propensity” of bio-binders obtained by partially replacing a conventional bitumen with a bio-oil generated as a residue by the wood and paper industries. Specifically, the objectives are: 1) to assess the effectiveness of bio-binders in the hot recycling of traditional RA and 2) to evaluate, in a long-term perspective, their recyclability potential. For this purpose, two severely aged binders (one “RAP” binder recovered from reclaimed asphalt and one laboratory-produced “Bio-RAP” binder) and two fresh binders (one bio-binder and one bitumen) are blended to reproduce four hot recycled binders. The mechanical behaviour and the aging susceptibility of these blends are compared to those of a control virgin bitumen. The experimental investigation includes conventional tests, rheological testing and modelling (modified CAM model) as well as chemical analysis (Fourier transform infrared spectroscopy). The main results indicate that the hot recycling of reclaimed bio-asphalt (bio-RA) may lead to mixtures less susceptible to cracking as compared to the recycling of conventional RA, as well as the use of bio-binders in the hot recycling of conventional RA may be beneficial in terms of cracking. Even though the blends with the bio-binder are characterized by a lower aging rate, the permanent deformation behaviour of all the recycled blends studied is comparable in unaged and short-term aged conditions, i.e. the circumstances under which rutting is usually a concern. Finally, the recycled blends show significantly lower aging susceptibility than the control bitumen. Overall, these results suggest that the bio-binders studied are effective in the hot recycling of RA and 100% recyclable, and their use in asphalt pavements can lead to significant technical and environmental benefits.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276996

Comparing the field and laboratory curing behaviour of cold recycled asphalt mixtures for binder courses
MATERIALS
Autore/i: Ferrotti, G.; Grilli, A.; Mignini, C.; Graziani, A.
Classificazione: 1 Contributo su Rivista
Abstract: The cold recycling of reclaimed asphalt (RA) for the rehabilitation of end-of-life pavements is becoming very common. Cold recycled asphalt mixtures (CRAMs) are characterised by a curing time, required to reach the material design mechanical performance. Since the laboratory simulation of the long-term field curing is not yet a standardised procedure, a CRAM was laid as binder course in a full-scale trial section that was monitored for more than two years. The comparison between field curing and oven-curing in laboratory at 40◦C was performed by carrying out indirect tensile stiffness modulus (ITSM), indirect tensile strength (ITS) and complex modulus tests, as well as measurements of the air voids content. The evolution of the ITSM as a function of the curing time (field/oven-curing) was obtained for both gyratory specimens and cores taken from the trial section at different time periods. Results showed that the material stiffness development can be accelerated with a small effect on its long-term value if oven-curing is applied a few days/weeks after compaction. A linear relationship was found between the ITS measured on the cores and their air voids content. Finally, the complex modulus tests confirmed that CRAMs provide an intermediate behaviour between asphalt concrete mixtures and cement-bound mixtures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/286852

Analysis of shear-torque fatigue test for bituminous pavement interlayers
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ragni, D.; Ferrotti, G.; Petit, C.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: The laboratory characterisation of bituminous interlayers is a challenging issue because of the difficulty of establishing loading conditions that can simulate field behaviour. This paper describes a shear-torque fatigue test procedure aimed at investigating the fatigue behaviour of bituminous pavement interlayers. A preliminary experimental investigation, able to evaluate the damage process occurring in both single- and double-layered specimens, showed that the presence of the interface constitutes a weakness zone, noticeably influencing the shear fatigue performance of the pavement structure. Thus, a model for the description of the evolution of the interlayer damage by using the variation of the interlayer complex shear modulus was proposed and preliminarily validated. Moreover, a new fatigue failure criterion has been proposed to be used in the result analysis of the shear-torque fatigue tests.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/280048

Research and Engineering for Resilient Infrastructures and Environment Protection
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Bocci, Maurizio; Brocchini, Maurizio; Canestrari, Francesco; Cardone, Fabrizio; Corvaro, Sara; Darvini, Giovanna; Ferrotti, Gilda; Graziani, Andrea; Lorenzoni, Carlo; Mancinelli, Alessandro; Postacchini, Matteo; Soldini, Luciano; Virgili, Amedeo
Classificazione: 2 Contributo in Volume
Abstract: We discuss the contribution of the research groups that work at UNIVPM in the field of infrastructure engineering to the design of resilient hydraulic and transportation infrastructures and related solutions for the protection of the environment. After recalling the long history of research and engineering intervention of the groups of Hydraulics and Transportation Infrastructures of UNIVPM, we show how the activities of such groups are becoming of increasing importance in response to the growing request of innovative solutions for resilient infrastructures (e.g. coastal protection and maritime structures, road and airport pavements) and environment protection (e.g. coastal and river flood, air pollution, waste recycling and materials reuse). Such activities have been recently boosted by the resources made available to the two groups through the “Dipartimenti di Eccellenza” award, which largely focuses on the issue of engineering for resilient built and natural environments. A projection in the future of the activities of above is also proposed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273420

Influence of chemical additives for warm mix asphalts on the short-term ageing of a plain bitumen
ROAD MATERIALS AND PAVEMENT DESIGN
Autore/i: Ragni, D.; Ferrotti, G.; Lu, X.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: Over the last years, the use of warm mix asphalt (WMA) in asphalt industry allows important reductions in production and compaction temperatures guarantying relevant environmental benefits. However, the most proper laboratory procedure for short-term ageing of WMAs must still be defined. This study aims at evaluating the effect of temperature and chemical additives on bitumen short-term ageing. For this purpose, a 70/100 pen-grade bitumen and two chemical additives were investigated in terms of conventional (penetration, softening point), viscosity and rheological tests, as well as FTIR-ATR analysis. As expected, binders aged at lower temperatures show reduced oxidation as compared to those aged at higher temperatures, implying a lower oxidative hardening. In general, aged binders containing the chemical additives show a reduction of the effect of ageing, or anti-ageing effect. Moreover, the rheological model parameters of the binders present good correlations with penetration values and softening point temperatures, as well as with the chemical parameters determined by FTIR-ATR.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276992

Renewable materials in bituminous binders and mixtures: speculative pretext or reliable opportunity?
RESOURCES CONSERVATION AND RECYCLING
Autore/i: Ingrassia, L. P.; Lu, X.; Ferrotti, G.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: Bitumen is the most employed binder in road pavements and derives from petroleum, which is a non-renewable resource that is progressively depleting. Therefore, the current challenge for road industry is to use renewable materials (i.e. bio-materials not subjected to depletion) in partial replacement of bitumen, thus reducing carbon footprint and making the sector less dependent on petroleum-based products. Specifically, the trend is to utilize bio-materials that are obtained as by-products from industrial processes or as wastes from the everyday life, avoiding their disposal in landfills, in accordance with the principles of sustainability and circular economy. Thus, research in this field is very promising and attractive nowadays. However, in order to understand whether the application of renewable materials represents a reliable and viable solution or just a speculative pretext for research, a rigorous scientific approach must be adopted. For this purpose, the paper provides an overview of the use of renewable materials in bituminous binders and mixtures, focusing on the necessary requirements that they should meet, their effects on performance, and health, safety and environment aspects. Based on the analysis of available literature, a comprehensive experimental approach for evaluating bio-materials in bituminous applications is also proposed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263622

Recommendations of RILEM TC 252-CMB on the Effect of Short Term Aging Temperature on Long Term Properties of Asphalt Binder
RILEM Bookseries
Autore/i: Poulikakos, L. D.; Hofko, B.; Cannone Falchetto, A.; Porot, L.; Ferrotti, G.; Mikhailenko, P.
Editore: Springer Netherlands
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Rilem Technical Committee on Chemo Mechanical Characterization of Bituminous Materials has investigated the effect of short term aging tempera-ture on long term properties of asphalt binder, chemically, physically and mi-crostructurally. The increased use of warm mix asphalt (WMA) technologies warrants such investigations in order to validate laboratory aging procedures. To this end, penetration, softening point, Fourier Transform Infrared Spec-troscopy, dynamic shear rheology (DSR) and electron microscopy (ESEM) were used. The experimental results on binders and warm (WMA) and hot (HMA) mixtures from nine participating laboratories indicate that the binder source, as well as method of evaluation, result in different rankings and be-haviors among the four binders used. The TC recommends the development of appropriate RTFOT aging temperatures for the simulation of binder aging in WMA.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/280045

Comparison of short term laboratory ageing on virgin and recovered binder from HMA/WMA mixtures
RILEM Bookseries
Autore/i: Ferrotti, Gilda; Baaj, Hassan; Besamusca, Jeroen; Bocci, Maurizio; Cannone Falchetto, Augusto; Grenfell, James; Hofko, Bernhard; Porot, Laurent; Poulikakos, Lily D.; You, Zhanping
Editore: Springer Netherlands
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Oxidative ageing strongly affects asphalt mixture behavior. The Rolling Thin Film Oven Test (RTFOT) is currently used to simulate within a laboratory environment the binder short-term ageing, assuming that the mixture is produced at conventional Hot Mix Asphalt (HMA) temperatures (ca 160 °C). However, the introduction of Warm Mix Asphalts (WMAs), which are produced at lower temperatures than HMAs, could require adjustments in the short-term ageing simulation procedure as ageing is strongly influenced by the mixing and compaction temperatures. In this study, the physical properties of a straight-run bitumen, before ageing and after RTFOT ageing at two temperatures (123 °C and 163 °C), are compared to those of the same bitumen recovered from a HMA and a foamed WMA, both produced in laboratory. This comparison aims at determining the best RTFOT temperature for short-term ageing simulation for WMAs. To this end, all the binders were investigated through conventional (penetration value at 25 °C and softening point temperature) and rheological (frequency sweeps with dynamic shear rheometer) tests. Both conventional and rheological tests indicate that the WMA recovered binder is less aged than the binder aged at the standard conditioning temperature of 163 °C, whereas the HMA recovered binder is more aged than the artificially aged binder in the laboratory with RTFOT at 163 °C. These initial results support the idea that an appropriate ageing temperature for RTFOT short-term ageing simulation of WMA needs to be identified.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/265195

Chemical and rheological investigation on the short- and long-term aging properties of bio-binders for road pavements
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ingrassia, L. P.; Lu, X.; Ferrotti, G.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: In recent years, due to growing environmental concerns, sustainability and circular economy have become two issues of crucial importance. In road engineering, in order to pursue such principles, one of the main current trends is to employ industrial residues and by-products deriving from renewable materials in partial substitution of petroleum-based bitumen. However, uncertainty on the durability and long-term performance of such materials still exists. In this regard, this paper focuses on the short- and long-term aging properties of bio-binders obtained by partially replacing a 50/70 bitumen with different percentages of a renewable bio-oil generated as a by-product by the wood and paper industries. The experimental investigation carried out includes conventional tests, chemical analyses as well as rheological testing and modelling with 2S2P1D model. Conventional bitumens were also tested for comparison purposes. The main chemical results indicate that, despite a small amount of additional oxidized compounds related to esters, the bio-oil addition significantly inhibits the formation of carbonyl compounds and reduces the aromaticity of the binders. In terms of performance-related properties, the permanent deformation resistance and the fatigue resistance of these bio-binders are generally comparable to those of traditional bitumens having similar penetration grade, without any specific drawback. Moreover, a linear material-dependent relationship was found between chemical and rheological changes induced by aging as well as the chemical and rheological parameters most strictly related to the binders’ oxidation were identified and considered as aging indicators. Based on the evolution of these parameters, the bio-binders investigated in this study may have comparable or even better aging resistance with respect to conventional bitumens with similar penetration grade. Therefore, such bio-binders can be considered an effective sustainable alternative to traditional bituminous binders.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276994

Recommendations of RILEM TC 252-CMB: relationship between laboratory short-term aging and performance of asphalt binder
MATERIALS AND STRUCTURES
Autore/i: Poulikakos, L. D.; Hofko, B.; Cannone Falchetto, A.; Porot, L.; Ferrotti, G.; Grenfell, J.
Classificazione: 1 Contributo su Rivista
Abstract: This recommendation reports on the effect of the Rolling Thin Film Oven Test (RTFOT) aging temperature on chemo-mechanical properties of asphalt binders for Warm Mix Asphalts. The RTFOT testing temperature should ideally replicate physical and chemical short-term aging of asphalt mixtures. The relevance of this was investigated in light of the increased use of warm mix asphalt technologies. The recommendations are based on round robin experiments performed by nine participating laboratories and consisting of a series of tests including experimental results on penetration, softening point temperature, Fourier Transform Infrared Spectroscopy and Dynamic Shear Rheology. The results indicate that the current RTFOT aging temperature does not replicate the aging in the mixture. For this reason, the TC recommends the selection of appropriate RTFOT aging temperatures in order to simulate binder aging as a result of various mixing technologies. The sulfoxide index is proposed as a measure of oxidative short term RTFOT aging.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276258

Sustainable Engineering for Resilient Built and Natural Environments
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Alici, Antonello; Bocci, Maurizio; Bonvini, Paolo; Brocchini, Maurizio; Calamai, Alessandro; Canestrari, Francesco; Capozucca, Roberto; Carbonari, Alessandro; Carbonari, Sandro; Cardone, Fabrizio; Clementi, Francesco; Clini, Paolo; Cocchi, Giammichele; Corvaro, Sara; Darvini, Giovanna; Davì, Fabrizio; Dezi, Luigino; Di Giuseppe, Elisa; D’Orazio, Marco; Ferretti, Maddalena; Ferrotti, Gilda; Gara, Fabrizio; Giretti, Alberto; Graziani, Andrea; Lancioni, Giovanni; Lemma, Massimo; Lenci, Stefano; Lorenzoni, Carlo; Malinverni, Eva Savina; Mancinelli, Alessandro; Mariano, Fabio; Mentrasti, Lando; Mondaini, Gianluigi; Montecchiari, Piero; Munafò, Placido; Naticchia, Berardo; Postacchini, Matteo; Quagliarini, Enrico; Quattrini, Ramona; Ragni, Laura; Serpilli, Michele; Soldini, Luciano; Virgili, Amedeo; Zampini, Giovanni
Editore: Springer
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272866

Advanced interface testing of grids in asphalt pavements
RILEM State-of-the-Art Reports
Autore/i: Canestrari, Francesco; D’Andrea, Antonio; Ferrotti, Gilda; Graziani, Andrea; Partl, Manfred N.; Petit, Christophe; Raab, Christiane; Sangiorgi, Cesare
Editore: Springer Netherlands
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/254084

Comparison between bitumen aged in laboratory and recovered from HMA and WMA lab mixtures
MATERIALS AND STRUCTURES
Autore/i: Ferrotti, Gilda; Baaj, Hassan; Besamusca, Jeroen; Bocci, Maurizio; Cannone-Falchetto, Augusto; Grenfell, James; Hofko, Bernhard; Porot, Laurent; Poulikakos, Lily; You, Zhanping
Classificazione: 1 Contributo su Rivista
Abstract: Oxidative ageing is an important phenomenon affecting asphalt concrete. Currently, binder short-term ageing, occurring during mixture production and laying, is simulated worldwide through rolling thin film oven test (RTFOT), which was developed assuming that the mixture is produced at conventional hot mix asphalt (HMA) temperatures around 160 °C. However, since ageing is strongly influenced by temperature, lower production temperatures imply less material ageing so that the introduction of warm mix asphalt (WMA) technologies could potentially require some adjustments in the ageing simulation procedures. This study aims at determining which RTFOT temperature simulates WMA short-term ageing more closely. To this end, the chemical and the mechanical characteristics of one type of bitumen, recovered from two asphalt mixtures (WMA and HMA) prepared and short-term aged in laboratory, were compared to those of the same virgin binder short-term aged in laboratory with RTFOT at different temperatures (123 °C and 163 °C). Both conventional and rheological tests show higher ageing levels for the binder recovered from HMA with respect to the binder aged with RTFOT at 163 °C, whereas the binder recovered from WMA generally provides an ageing level lower than the binder aged with RTFOT at 163 °C. These results are also confirmed by the chemical analysis using FTIR which indicate higher oxidation levels for the hot mix process compared to the warm mix. These preliminary results confirm that it is necessary to identify an appropriate ageing temperature for the short-term ageing simulation of WMAs with RTFOT.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/265194

Effect of temperature and chemical additives on the short-term ageing of polymer modified bitumen for WMA
MATERIALS & DESIGN
Autore/i: Ragni, D.; Ferrotti, G.; Lu, X.; Canestrari, F.
Classificazione: 1 Contributo su Rivista
Abstract: Nowadays warm mix asphalt (WMA) is recognized as a very competitive alternative to hot mix asphalt (HMA). This technology allows to obtain an excellent and environmentally-friendly material for road construction. This paper focuses on the effect of a reduced short-term ageing temperature on the binder behaviour and on the effect of WMA chemical additives on the performance of short-term aged binders. Three asphalt binders (one polymer modified bitumen combined with two WMA chemical additives) were aged through the rolling thin film oven test (RTFOT) at different temperatures (120, 130 and 163 degrees C). Conventional, rheological and chemical tests were used for characterising the binders. Lower ageing temperatures provided reduced oxidation, implying lower oxidative hardening but also reduced permanent deformation resistance. A general reduction of ageing effects is observed in the WMA binders, with both positive (moderate deceleration of the ageing process) and negative (more noticeable reductions in the permanent deformation resistance) outcomes. The microscopic analysis showed that the chemical additive likely alters the structural interactions of bitumen and polymer. A comparison between WMA binders short-term aged in laboratory and in field, indicates that the RTFOT performed at reduced temperature could properly simulate the field ageing when WMA production temperatures are considered.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263651

Tribological characterization of bituminous binders with Warm Mix Asphalt additives
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ingrassia, L. P.; Lu, X.; Canestrari, F.; Ferrotti, G.
Classificazione: 1 Contributo su Rivista
Abstract: Warm Mix Asphalt (WMA) technologies allow reducing production, laying and compaction temperatures of bituminous mixtures, leading to relevant environmental and technical benefits. According to recent studies, some WMA additives lead to this temperature reduction by potentially improving the lubricating properties (i.e. the tribological behaviour) of the bituminous binder. In this study, the effect of a chemical and a wax additive on the tribological behaviour of two base bituminous binders was investigated, by considering different percentages of additive. All the binders were preliminarily characterized with Fourier Transform Infrared Spectroscopy (FTIR) and viscosity analysis. After optimizing the test procedure, tribological tests were carried out with a ball-on-three-plates fixture at 85 °C and 120 °C. A statistical analysis was also performed on the tribological results to evaluate the statistical significance of the differences between the binders. Results showed that the additives might alter the oxidative state of the binder, the chemical additive is able to modify the tribological behaviour of the binder, the wax additive acts solely on the viscosity and the effect of the additive depends on the chemical composition of the base binder. Moreover, a correlation between the minimum friction and the viscosity was found.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263628

Effect of warm mix asphalt chemical additives on the mechanical performance of asphalt binders
MATERIALS AND STRUCTURES
Autore/i: Ferrotti, Gilda; Davide, Ragni; Lu, Xiaohu; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Warm mix asphalt (WMA) has become very popular in asphalt pavement construction because it allows reducing both energy consumptions and carbon emissions.WMA can be obtained by using different types of additives and can be produced, applied, and compacted at temperatures 20–40 °C lower than hot mix asphalt. WMA additives allow reducing the working temperatures without compromising the final performance of the asphalt concrete. Many WMA additives are available on the worldwide market and some of them reduce the viscosity of asphalts binder (organic additives or foam) whereas others do not act on this sense (chemical additives). This study focuses on the effect of chemical additives on the performance of asphalt binders for WMA production. To this purpose, a neat bitumen, a polymer modified bitumen (PMB) and two different chemical additives were selected. All the binders were characterized through conventional tests, DSR, MSCR, FTIR and microscopic analysis. The result clearly showed that the influence of the chemical additives on the neat bitumen is negligible or non-existent. On the contrary, significant changes were observed in the modifiedbitumen properties. Specifically, chemical additives reduce the viscosity temperature susceptibility of PMBs in the temperature range between 80 and 140 °C, increase the rutting resistance potential and the elastic response of PMBs at high temperatures. Moreover, a morphological inspection supported the modifications observed in the rheological properties of PMBs.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/254765

State of the art of tribological tests for bituminous binders
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Canestrari, Francesco; Ingrassia, LORENZO PAOLO; Ferrotti, Gilda; Lu, Xiaohu
Classificazione: 1 Contributo su Rivista
Abstract: Kinetic friction is a physical phenomenon which originates when two or more bodies are in contact and in relative motion, and causes energy consumption and wear. Lubricants are widely used in many fields to reduce kinetic friction and their behaviour is usually characterized through appropriate tribological tests. In fact, the science of tribology (from the Greek word “tribo” that means to rub and the Latin word “logia” that means study) investigates interactions between surfaces in relative motion. In the field of road materials, during asphalt mixing and compaction, bitumen acts similarly to lubricants, reducing friction between aggregates, and its lubricating properties significantly affect the energy required. According to recent studies, some Warm Mix Asphalt additives are able to reduce production and compaction temperatures (and therefore energy consumption) of asphalt mixtures by potentially improving the lubricating behaviour of the binder. Thus, tribological tests have recently been introduced in the investigation of bituminous binders to characterize their lubricating properties. This paper aims at providing the state of the art of tribological tests currently employed for the study of bituminous binders, as well as useful suggestions for improving these procedures. Since the introduction of such tests in the field of road materials is quite recent, an overview on tribology and tribological tests on common lubricants is presented, with the aim to highlight the main aspects to take into account when applying the tribological characterization of bituminous binders.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/254772

Time–temperature superposition principle for interlayer shear strength of bituminous pavements
ROAD MATERIALS AND PAVEMENT DESIGN
Autore/i: Graziani, Andrea; Canestrari, Francesco; Cardone, Fabrizio; Ferrotti, Gilda
Classificazione: 1 Contributo su Rivista
Abstract: Poor interlayer bonding leads to a reduction in service life of bituminous pavements, thus the identification and measurement of the parameters affecting interlayer shear strength (ISS) are becoming increasingly important. This study focuses on the effects of test temperature and interlayer deformation rate (IDR) on the ISS of double-layered asphalt concrete specimens, with the aim of comparing two different shear testing devices. Specifically, tests were performed by means of Ancona Shear Testing Research and Analysis and Leutner devices, at temperatures ranging from 5°C to 40°C and deformation rates ranging from 1 to 50 mm/min. Moreover, two interface conditions (with and without tack coat) were investigated. Experimental data showed that for both shear testing devices, higher IDR results in higher ISS, because of the time-dependent response of bituminous mixture and that the effect of IDR and temperature on ISS can be superposed allowing a master curve to be satisfactorily obtained using a three-parameter sigmoidal model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/246527

Geocomposite-reinforcement of polymer-modified asphalt systems
8th RILEM International Symposium on Testing and Characterization of Sustainable and Innovative Bituminous Materials
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Abuaddous, Musab; Pasquini, Emiliano
Editore: Kluwer Academic Publishers
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Geosynthetic reinforcement has proven to be an effective method to improve road pavement performance. In this regard, composite materials obtained combining bituminous membranes with reinforcing grids represent a promising option thanks to the waterproofing and stress-relieving effect produced by the membrane and the enhanced mechanical characteristics provided by the grid. This research had the objective of evaluating the effectiveness of pavement rehabilitation by means of an optimized composite material, consisting of an elastomeric bituminous membrane reinforced with a fiberglass grid, applied at the interface of a polymer-modified asphalt system. An unreinforced reference configuration was also investigated for comparison purpose. Interlayer shear tests and three-point bending tests were performed on double-layered specimens in order to evaluate bond strength at the interface and toughness (i.e. fracture resistance) of the pavement system, respectively. Shear tests showed that the reinforcement at the interface reduces the bonding between asphalt layers even if a residual cohesion contribution is provided after shear failure. As far as flexural properties are concerned, the real contribution of the reinforcement consists in the delay of crack propagation rather than in the inhibition of crack initiation.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/232970

Inter-laboratory shear evaluation of reinforced bituminous interfaces
8th RILEM International Symposium on Testing and Characterization of Sustainable and Innovative Bituminous Materials
Autore/i: Ferrotti, Gilda; D’Andrea, Antonio; Maliszewski, Maciej; Partl, Manfred Norbert; Raab, Christiane; Sangiorgi, Cesare; Canestrari, Francesco
Editore: Kluwer Academic Publishers
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Over the last decades, the use of grids between asphalt layers has been gaining interest. Several test methods have been proposed in order to simulate the complex mechanical behavior of reinforced pavements and to assist practitioners in the selection of the appropriate reinforcement product. For this purpose, the Task Group 4 (Pavement Multilayer System Testing) of the RILEM technical committee TC 237-SIB (Testing and Characterization of Sustainable Innovative Bituminous Materials and Systems) organized an inter-laboratory experiment, constructing one trial test section to obtain double-layered asphalt pavement samples for the participating laboratories. The experiment placed two grid types (a glass fiber reinforced polymer grid and a carbon fiber/glass fiber pre-bituminised grid) between two asphalt layers, thereby creating two reinforced double-layered systems. As a control, an unreinforced interface was also realized. This paper presents the overall results of interlayer shear tests carried out by five participating laboratories using five different shear testing methodologies. The objective is to show the effect of two grid types on the shear behaviour of reinforced double-layered systems and to compare the findings which emerged from using different test devices and methods under different testing conditions (e.g. sample geometry, temperature, loading time, normal stress). Consistent and reliable results have been obtained through the various methodologies adopted. It has been observed that grid-reinforced samples provide lower interlayer shear strength compared with unreinforced samples. Glass-fiber grid system, which is of greater thickness and greater torsional stiffness, displayed less shear strength than carbon fiber/glass fiber-reinforced grid systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/232937

Fatigue rheological characterization of polymer-modified bitumens and mastics
RILEM Bookseries - 8th International RILEM Symposium on Testing and Characterization of Sustainable & Innovative Bituminous Materials
Autore/i: Frigio, Francesca; Ferrotti, Gilda; Cardone, Fabrizio
Editore: Springer Science + Business Media
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Fatigue is one of the major distresses of flexible pavements and is mainly related to the rheological properties of the bituminous components of mixtures. In particular, bitumen and mineral filler create a blend called mastic that significantly influences the service life of asphalt pavements depending on its nature and com- position. The purpose of this study is to investigate the effects of different polymer types and mineral fillers on the rheological behavior of a plain bitumen. Two types of polymer (an elastomer and a plastomer) were employed to produce polymer modified bitumens (PMBs) through laboratory mixing. Moreover, two fillers characterized by a different mineralogical nature (limestone and basalt) were selected in order to obtain several mastics. The dynamic shear rheometer (DSR) was used to study the fatigue behavior of all materials. Experimental data show that the effect of both polymer types is similar on mastics and bitumens as the presence of the elastomer leads to an improvement in fatigue life whereas the presence of the plastomer leads to a slight decrease in fatigue performance with respect to the plain bitumen, regardless of the mineral filler type. Moreover, the stiffening effect of mineral fillers was found to be significant regardless of filler mineralogy and bitumen type leading to a decrease in fatigue life with respect to bitumens. All mastics were less sensitive to the strain level applied as compared to the corresponding bitumens.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228644

Influence of Specimen Dimension and Test Speed on the Shear Strength of Bituminous Interfaces
8th International RILEM Conference on Mechanisms of Cracking and Debonding in Pavements
Autore/i: Abuaddous, Musab; Canestrari, Francesco; Graziani, Andrea; Ferrotti, Gilda
Editore: A. Chabot; W.G. Buttlar; E.V. Dave; C. Petit; G. Tebaldi
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In view of the fact that pavements are multilayer systems, achieving high bonding between layers is a key element to increase service life. Interface debonding is mainly responsible for the slipping failure of pavements that leads to high rehabilitation and maintenance costs. The bonding between asphalt layers is usually evaluated by testing the interlayer shear strength and is affected by several parameters such as test speed, test temperature, normal stress applied and specimen diameter. This paper focuses on the effect of test speed and specimen diameter on the shear strength evaluated through the Leutner equipment, for a typical dense graded asphalt mixture. Leutner tests were carried out on double-layered specimens with a diameter of 100 and 150 mm and with interlayer deformation rates corresponding to nominal test speeds of 1, 2.5, 5, 10, 25 mm/min. The effective interlayer deformation rate was calculated by measuring the deformation through an external transducer in order to perform a reliable data analysis. Results showed a steady increase in the shear strength with the increase in the interlayer deformation rate. Moreover, a clear scale effect was observed at any test speed resulting in higher values for shear strength measured on specimens with diameter of 100 mm.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/238119

Shear failure characterization of time-temperature sensitive interfaces
MECHANICS OF TIME-DEPENDENT MATERIALS
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Graziani, Andrea
Classificazione: 1 Contributo su Rivista
Abstract: Poor interlayer bonding can lead to early failures and thus to a reduction in service life of bituminous pavements. For this reason, it is important to identify the parameters influencing the interlayer shear failure and to characterize their effect by means of laboratory test. In particular, this study is focussed on the effects of test temperature and deformation rate on the interlayer shear strength (ISS) of double-layered asphalt concrete specimens. First, the ISS was measured at temperatures ranging from 0 °C to 30 °C and deformation rates ranging from 0.5 mm/min to 9 mm/min using the Ancona Shear Testing Research and Analysis (ASTRA) device. Then the experimental data were analyzed using a two-stage statistical modelling approach. In the first stage, the variation of ISS versus deformation rate, at each testing temperature, was modelled using both a power-law and a logarithmic function. In the investigated range of deformation rate, the models allowed to estimate the mean ISS with residual standard error varying from 0.062 MPa to 0.128 MPa. Moreover, the linear regression coefficients, which measure the influence of the deformation rate on ISS, changed with temperature. In the second stage, both temperature and deformation rate were used as joint predictors of ISS by using an approach based on the superposition of their effects. Results showed that the time–temperature superposition approach is applicable and a sigmoid-shaped master curve for ISS was obtained. The proposed approach was validated by using ISS measurements obtained on the same materials with different test devices.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/238105

Validation of a hydraulic model to prevent emulsion flowing in chip sealing
INTERNATIONAL JOURNAL OF PAVEMENT RESEARCH AND TECHNOLOGY
Autore/i: Giuliani, Felice; Ferrotti, Gilda; Montepara, Antonio; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Chip sealing is a pavement surface treatment that consists in the application of an asphalt binder (bitumen or bituminous emulsion) on an existing pavement followed by the spreading of aggregate chips and by the rolling of the surface, in order to embed the aggregate into the binder. This treatment is typically used as preventive maintenance technique of asphalt pavements, in order to seal fine cracks and improve skid-resistance of road surfaces. Moreover, chip sealing is often employed on rural roads, that carry low traffic volumes and are often characterized by critical conditions such as small radius of curvature and/or high longitudinal slopes. In the latter case, the application of the bituminous emulsion becomes a crucial concern as an excessive flowing of the bitumen could take place due to the high pavement slope and its spreading could become not uniform. In order to investigate these aspects, in this study ahydraulic model of the theoretical flow of bituminous emulsions on high longitudinal slope road surfaces was proposed and validated through a laboratory experimental investigation. To this aim, an original laboratory equipment (Chip Seal Laboratory Simulator), that allows the simulation of the most critical conditions during field activities, was properly designed and realized. The theoretical analysis and the experimental validation suggested practical recommendations in terms of longitudinal working speeds in critical contexts, very usual in practice.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/232924

Performance evaluation of hot recycled mixtures containing sbs modified binder
Bituminous Mixtures and Pavements VI - Proceedings of the 6th International Conference on Bituminous Mixtures and Pavements, ICONFBMP 2015
Autore/i: Stimilli, Arianna; Ferrotti, Gilda; Radicioni, Daniele; Canestrari, Francesco
Editore: CRC Press/Balkema
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Over the last decades, Reclaimed Asphalt Pavement (RAP) has become one of the most recycled materials. Currently, RAP is mainly used for unbound layers, without exploiting the replacement of a portion of the more expensive virgin binder. Moreover, the increasing quantity of RAP which includes aged modified binders complicates material analysis. This paper presents a laboratory mechanical investigation on hot recycled mixtures prepared with RAP including aged Styrene-Butadiene-Styrene (SBS) modified binder. A reference mixture with 25% RAP and four mixtures with 40% RAP were investigated. Two total binder contents and two virgin SBS modified binders were used to produce mixtures with 40% RAP, which were designed using the Bailey method. Compactibility, stiffness properties, cracking and rutting resistance were evaluated on laboratory compacted specimens. Results suggest that amounts of RAP up to 40% are suitable for the production of new bituminous materials, when a specific and detailed mix design is performed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/232927

Influence of mineral fillers on the rheological response of polymer-modified bitumens and mastics
JOURNAL OF TRAFFIC AND TRANSPORTATION ENGINEERING
Autore/i: Cardone, Fabrizio; Francesca, Frigio; Ferrotti, Gilda; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The rheological properties of the bituminous components (bitumen and bituminous mastic) within asphalt mixtures contribute significantly to the major distresses of flexible pavements (i.e. rutting, fatigue and low temperature cracking). Asphalt mixtures are usually composed of mastic-coated aggregates rather than pure bitumen-coated aggregates. The purpose of this study is to investigate the effects of mineral fillers on the rheological behaviour of several polymer-modified bitumens (PMBs) through laboratory mixing. A neat bitumen and two types of polymers (elastomeric and plastomeric) were used to produce PMBs, and two fillers with different minerals (limestone and basalt) were selected to obtain mastics. The dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were used to characterize the rheological properties of PMBs and mastics. In particular, multiple stress creep recovery (MSCR) tests were performed to evaluate the rutting potential at high temperatures, whereas BBR tests were carried out to investigate the low temperature behaviour of these materials. BBR results for unmodified mastics show that the increase of stiffness is similar regardless of the filler type, whereas results for polymer-modified mastics indicate that the degree of stiffening depends on the combination of filler/polymer types. MSCR results show that adding filler leads to a reduced susceptibility of permanent deformation and an enhanced elastic response, depending on the combination of filler/polymer types. Overall results suggest that a physicalechemical interaction between the filler and bitumen occurs, and that the interaction level is highly dependent on the type of polymer modification.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228649

Shear and flexural characterization of grid-reinforced asphalt pavements and relation with field distress evolution
MATERIALS AND STRUCTURES
Autore/i: Canestrari, Francesco; Belogi, Leonello; Ferrotti, Gilda; Graziani, Andrea
Classificazione: 1 Contributo su Rivista
Abstract: The use of geogrids at the interface of asphalt layers is currently adopted to improve pavement performance in terms of rutting, fatigue and reflective cracking. Several test methods have been proposed in order to simulate the complex mechanical behavior of reinforced pavements and assist practitioners in the selection of the appropriate reinforcement product. A particular subject of debate is the evaluation of geogrid effects in terms of both flexural strength and interlayer bonding. In this context, an interlaboratory experiment has been organized as part of the RILEM TC 237-SIB/TG4 with a twofold objective: to compare the predictive effectiveness of different experimental approaches and to analyze the behavior of different geogrid types. For this purpose two experimental reinforced test sections have been realized, the first one to prepare samples for the interlaboratory experiment, the second one to analyze the geogrid field performance under heavy traffic conditions. This paper describes the test results obtained by one participating laboratory on double-layered asphalt samples extracted from the first experimental section and compares them with the periodic visual observation of the reflective cracking evolution occurred in the second test section. The laboratory tests were performed following a specific testing protocol that combines interlayer shear tests, repeated loading tests in a four-point bending configuration and quasi-static three-point bending tests, in order to investigate the overall performance of double-layered asphalt systems. Results have shown that geogrid reinforcement does not noticeably influence the flexural stiffness and strength in the pre-cracking phase, whereas the crack propagation speed can be significantly reduced and the failure behavior may change from quasibrittle to ductile, depending on the interlayer shear resistance. Laboratory results were confirmed by periodic visual observation of field performance in terms of reflective cracking evolution.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/127272

Innovative testing protocol for the evaluation of binder-reclaimed aggregate bond strength
TRANSPORTATION RESEARCH RECORD
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Cardone, Fabrizio; Stimilli, Arianna
Classificazione: 1 Contributo su Rivista
Abstract: The durability of asphalt mixtures is strongly related to the adhesion properties developed at the interface between binder and aggregates. The loss of adhesion implies a rapid deterioration (e.g. stripping, raveling) of pavement layers under traffic loads, especially when the pavement is affected by the presence of moisture. Adhesion is a complex phenomenon related to the mineralogical and morphological nature of aggregates, as well as to the chemical binder composition and the environmental conditions. Nowadays, its evaluation becomes even more complicated as an increasing percentage of Reclaimed Asphalt is used in the production of new asphalt mixes. Therefore, adhesion properties are also related to the mechanisms developed at the interface between virgin binder and aged binder that coats the Reclaimed Asphalt aggregate surface. An innovative procedure to evaluate the compatibility of the system virgin binder/Reclaimed Asphalt aggregate is proposed in this study. This procedure allows to simulate in laboratory the substrate of a Reclaimed Asphalt aggregate and can integrate the Binder Bond Strength test currently used to investigate bonding properties and water sensitivity of the system binder-virgin aggregates. Tests were conducted using different aggregate sources, several modified binders and two conditioning types (dry, wet). It was found that this procedure is able to catch the differences between different test configurations and variables. In particular, the artificial reclaimed aggregate substrate ensured higher adhesion performance compared to the virgin aggregate, especially in wet condition, regardless the modification level of the virgin bitumen adopted.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/149303

Full-depth reclamation for the rehabilitation of local roads: a case study
INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING
Autore/i: Bocci, Maurizio; Grilli, A.; Cardone, Fabrizio; Ferrotti, Gilda
Classificazione: 1 Contributo su Rivista
Abstract: Full-depth reclamation (FDR) techniques for pavement construction and rehabilitation have gained general recognition because of their technical, economical and environmental advantages. The use of cement–bitumen-treated material (CBTM) has rapidly increased over the last 10 years mainly in motorways. Public administrations have recognised the advantages of FDR, and this technique has also begun to be applied for the rehabilitation of local and/or rural roads. This paper shows the results from a trial section built to verify the suitability of FDR for the rehabilitation of local roads. The design planned the in situ stabilisation with styrene-butadiene-styrene (SBS)-modified bituminous emulsion and cement of hot mix asphalt and foundation course. The mechanical characteristics of CBTM were evaluated by means of stiffness modulus tests at different temperatures and fatigue tests. The obtained results offer good prospects for the application of FDR in the maintenance project of local roads.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/149302

Chemical and rheological analysis of modified bitumens blended with "artificial reclaimed bitumen"
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Stimilli, Arianna; Ferrotti, Gilda; Conti, Carla; Tosi, G.; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Bitumen characteristics are fundamental for the development of good performance in asphalt mixtures, particularly when the mix includes Reclaimed Asphalt (RA) as aged bitumen can strongly affect the properties of the final bituminous phase. In this study three modified bitumens with different contents (1.8%, 2.8% and 3.8%) of SBS polymer were selected. Blends of these bitumens with various percentages of an artificial reclaimed bitumen (itself polymer modified), long-term aged in laboratory, were analyzed. A chemical characterization together with classical and innovative rheological tests were performed. The chemical investigation conducted using FTIR analysis showed that different percentages of artificial reclaimed bitumen included in the blends influence the final SBS amount. Rheological tests demonstrated that the addition of the artificial reclaimed bitumen does not penalize the final bituminous blend characteristics thereby indicating that the maximum amount of Reclaimed Asphalt incorporable in a mixture (according to the highest percentage of artificial reclaimed bitumen investigated) does not appear to be limited by the rheological characteristics of the final bituminous phase.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/174502

Influence of polymer modification on asphalt binder dynamic and steady flow viscosities
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Cardone, Fabrizio; Ferrotti, Gilda; Frigio, Francesca; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Asphalt pavement performance such as rutting, crack initiation and propagation as well as fatigue behaviour are substantially affected by the rheological properties of the bitumen. In this sense, the use of polymer modification in road paving applications has been growing rapidly over the last decade as it allows significant enhancements in bitumen properties with consequent improvement in road service life. In fact, the use of polymer modified bitumens (PMBs) leads to pavements characterized by higher resistance to rutting and thermal cracking and lower fatigue damage, stripping and thermal susceptibility. This paper presents a laboratory investigation concerning the effect of polymer modification on the flow behaviour of bitumens. Two different polymers, an elastomer and a plastomer, were used as bitumen modifying agents at three different percentages (2%, 4% and 6% by bitumen weight). Oscillatory mechanical analysis as well as viscosity measurements under steady state conditions were performed taking into account different testing parameters such as temperature, loading frequency and shear rate. The results confirm that the rheological properties of PMBs are strongly influenced by polymer nature and polymer content. The bitumen viscosity on the dynamic domain was combined with that in the steady-state domain, confirming the applicability of the Cox–Merz relationship for the plain bitumen and the PMBs with low polymer content. Finally, the Cross and the Carreau models were found to be suitable to fit the steady state and the dynamic results in order to determine the viscosity function of the investigated bitumens.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/189504

Experimental characterization of high-performance fiber-reinforced cold mix asphalt mixtures
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ferrotti, Gilda; Pasquini, Emiliano; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Maintenance of existing road pavements assumes increasing interest as the traffic growing produces a faster deterioration of road infrastructures compromising safety and pavement serviceability. In order to guarantee long-lasting pavement repairs, maintenance activities and products must be optimized in terms of both achieved performance and curing times to reach a proper pavement serviceability. This research project focuses on the experimental characterization of a high-performance cold mix asphalt mixture reinforced with three types of fibers (cellulose, glass–cellulose, nylon–polyester–cellulose) dosed at two different contents (0.15% and 0.30% by the aggregate weight). Such materials were investigated at different curing times (1, 7, 14, 28 days) and conditions (dry and wet). Laboratory tests (Marshall, Indirect Tensile, Abrasion and Compactability) usually employed for hot mix asphalts were considered, adjusting the testing procedures taking into account the specific characteristics of cold mixes. Results showed that the mix with 0.15% cellulose fibers provides similar (for curing times of 14 and 28 days) or even higher performance (for curing times within 7 days) than the standard mixture (without fibers). Finally, the last two mixtures were compared with two cold mix asphalt mixes available on the market. The cellulosefiber- reinforced material and the standard one showed enhanced performance, allowing the conclusion that they can be more successfully used in maintenance activities.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/174503

Structural response of grid-reinforced bituminous pavements
MATERIALS AND STRUCTURES
Autore/i: Graziani, Andrea; Emiliano, Pasquini; Ferrotti, Gilda; Virgili, Amedeo; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Grid reinforcement is becoming a standard construction and rehabilitation technique to improve the performance of bituminous pavements. Currently, selection of the appropriate grid type and position is based on empirical criteria or derived from the results of laboratory tests which consider a single aspect of the mechanical behavior of the grid-reinforced systems. An improvement in the existing design and testing approaches could be obtained considering the actual response of grid-reinforced systems under vehicular loads. An instrumented pavement section was constructed to achieve this objective by installing a glass fiber polymer grid (FP) and a carbon fiber/glass fiber grid (CF) inside a double-layered asphalt surfacing along an in-service road. This pavement is part of a wider project which also involves a RILEM inter-laboratory test on the same reinforced systems. The pavement response to falling weight deflectometer (FWD) and real-scale truck loads was measured using pressure cells and asphalt strain gauges installed inside the pavement. A layered elastic theory (LET) model was adopted to perform both back-calculation of layer moduli and forward-calculation (simulation) of pavement stress and strain. The FWD and the real-scale tests yielded congruent results highlighting that the strain field inside the double-layered surfacing was considerably reduced by the installation of the CF/glass fiber grid whereas the glass FP grid was probably too stiff, potentially leading to interface debonding. The LET model proved to be a simple and effective tool for a first-approach analysis of the reinforcement pavement response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/150303

Improved durability of recycled porous asphalt
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Frigio, Francesca; Pasquini, Emiliano; Ferrotti, Gilda; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Porous asphalt mixtures are extensively used as highway surface layer due to their benefit in improving skid resistance and reducing spray and splash effects during wet conditions. Moreover, porous asphalts (PA) are also oriented towards the reduction of road traffic noise thanks to enhanced sound absorption capabilities. Nevertheless, the limited durability of porous asphalt layers leads to frequent maintenance and rehabilitation activities. In this study, the use of course reclaimed asphalt (RA), obtained by milling old porous surface layers, as aggregate in new PA mixtures was evaluated. Preliminary, Binder Bond Strength tests on coated and uncoated basalt aggregate substrates showed encouraging results in terms of adhesion properties between unaged polymer modified bitumens and substrates coated with aged bitumens, simulating RA aggregates. Thus, five porous asphalt mixtures prepared with 15% course RA aggregates and different total binder contents were studied in the laboratory. A reference PA mixture containing only virgin aggregates was also investigated for comparison purposes. Indirect tensile strength tests, particle loss (Cantabro) tests, semi circular bending (SCB) tests and repeated indirect tensile tests were carried out in both dry and wet conditions in order to evaluate acceptability, durability, fracture resistance and water sensitivity of recycled mixtures. Results showed that recycled porous asphalt mixtures can perform as well as (or even better than) reference one. In particular, recycled mixtures at equal or higher binder contents than the reference mixture demonstrated an improvement in moisture resistance and durability.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/115068

Laboratory characterisation and field validation of geogrid-reinforced asphalt pavements
ROAD MATERIALS AND PAVEMENT DESIGN
Autore/i: Pasquini, Emiliano; Bocci, Maurizio; Ferrotti, Gilda; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: In order to improve the mechanical properties of pavements, reinforcement systems can be employed in asphalt layers. However, the presence of a grid at the interface causes an interlayer de-bonding effect. Moreover, a real challenge is related to the proper in situ installation of grids. The present research aims to evaluate the effectiveness of pavement rehabilitation with fibreglass geogrids. To this purpose, a real-scale field trial was constructed and monitored through Falling Weight Deflectometer measurements. Interface shear tests and flexural tests were also carried out on double-layered samples prepared in the laboratory reproducing realscale field trial characteristics. Moreover, shear tests were also performed on in situ cored specimens. Results mainly showed that a proper installation of the reinforcement is fundamental in order to obtain suitable test results and good pavement performance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/82572

Performance Evaluation of Cold Recycled Mixture Containing High Percentage of Reclaimed Asphalt
ROAD MATERIALS AND PAVEMENT DESIGN
Autore/i: Stimilli, Arianna; Ferrotti, Gilda; Graziani, Andrea; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Cold recycling of asphalt pavements proved to be an effective maintenance and rehabilitation technology for both environmental and economic reasons. Nevertheless, the use of cold-recycled (CR) asphalt mixtures requires a careful assessment of their mechanical properties, especially when they are designed to replace traditional hot-mix asphalt concrete (AC) mixtures. In this study, the potential use of a CR asphalt mixture as base course of an Italian motorway was evaluated. The studied mixture was produced in a central plant employing high-reclaimed asphalt (RA) content and used to construct two experimental sections along an in-service Italian motorway. In particular, a special mixing procedure, involving the use of water vapour and bituminous emulsion, was tested. A third experimental section was constructed with the same layer thickness using the AC mixture currently used in rehabilitation projects, incorporating 30% of RA. Volumetric properties, stiffness, resistance to permanent deformation and fatigue behaviour of mixtures were investigated by performing tests on samples cored from the three test sections and on laboratory-compacted samples. Results of the mechanical tests showed that CR mixtures provide lower stiffness modulus and lower resistance to repeated loading, but better resistance to permanent deformation when compared with AC. This behaviour can be explained due to the presence of cementitious bonds that reduce thermal sensitivity and viscous response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/115065

Mechanical Testing of Interlayer Bonding in Asphalt Pavements
State-of-the-Art-Report of the RILEM Technical Committee 206-ATB: Advances in Interlaboratory Testing and Evaluation of Bituminous Materials
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; X., Lu; A., Millien; M. N., Partl; C., Petit; A., Phelipot Mardelé; H., Piber; C., Raab
Editore: M.N.Partl, H.U. Bahia, F. Canestrari, C. de la Roche, H. Di Benedetto, H. Piber, D. Sybilski
Classificazione: 2 Contributo in Volume
Abstract: Steadily increasing requirements on pavement performance properties, in terms of bearing capacity and durability, as well as new innovative developments regarding pavement materials and construction, are observed worldwide. In this context interlayer bonding at the interfaces of multi-layered bituminous systems is recognized as a key issue for the evaluation of the effects, in terms of stress-strain distribution, produced by traffic loads in road pavements. For this reason a correct assessment of interlayer bonding is of primary importance, and research efforts should be addressed in order to improve the lack of correlation and/or harmonization among test methods. Following this principle RILEM TG 4 organized an interlaboratory test in order to compare the different test procedures to assess the interlayer bonding properties of asphalt pavement. The results of the experimental research are presented with a preliminary overview of basic elements, test methods and experimental investigations on interlayer bonding. Then the RILEM TG 4 experimental activities, based on the construction of three real-scale pavement sections, are presented in detail. Each pavement section wascomposed of two layers, and three different interface conditions were chosen. The first pavement was laid without interface treatment and the others with two different types of emulsion. Fourteen laboratories from 11 countries participated in this study and carried out shear or torque tests on 1,400 cores. The maximum shear or torque load and the corresponding displacement were measured, and the shear or torque strength was calculated as a function of the following parameters: diameter, test temperature, test speed, stress applied normal to the interface and age of the specimen. The results of this study are presented in terms of precision and correlations regarding the parameters which results in useful information on asphalt pavement interlayer bond tests.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/82957

Experimental evaluation of the influence of surface coating on fiberglass geogrid performance in asphalt pavements
GEOTEXTILES AND GEOMEMBRANES
Autore/i: Ferrotti, Gilda; Canestrari, Francesco; Pasquini, Emiliano; Virgili, Amedeo
Classificazione: 1 Contributo su Rivista
Abstract: In road infrastructures, the maintenance of existing pavements is one of the most important issues to deal with. In order to optimize rehabilitation costs and increase pavement service life, innovative technical solutions have been developed. One of the most widespread techniques introduced for this scope, consists in the application of geogrids at the interface between different layers of pavement structures. Geogrids provide different performance depending on their characteristics, such as constituent materials, surface coating, mesh geometry and dimensions, and on their position in the pavement structure. In fact, these materials can be placed between different layers (bounded and/or unbounded) carrying out different functions. In this survey, the reinforcement of asphalt concrete layers was studied in laboratory, paying particular attention to the effects that different surface coatings, consisting in different treatments of the surface of the mesh elements of the geogrid, produce on the performance of fiberglass reinforced asphalt concrete specimens. The experimental analysis was carried out in two different stages. During the first stage, the coatings themselves were investigated, studying their adhesion properties with a conventional asphalt binder, in order to check their capability to adhere to the constitutive material of an asphalt concrete. During the second stage, a specific testing protocol was followed in order to investigate the performance of double-layered asphalt concrete specimens by means of interlayer shear tests and four-point bending tests. The results showed that the testing protocol used is suitable for studying, in laboratory, the performance of reinforced pavements, that could be influenced, both in terms of interlayer bonding between asphalt concrete layers and four-point bending test characteristics, by the application of a coating on the surface of the geogrids.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/71051

An application to the European practice of the Bailey Method for HMA aggregate grading design
PROCEDIA: SOCIAL & BEHAVIORAL SCIENCES
Autore/i: Graziani, Andrea; Ferrotti, Gilda; Pasquini, Emiliano; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The Bailey Method provides a set of tools for the design and the evaluation of aggregate packing and voids of asphalt concrete grading while maintaining appropriate mixture workability and durability. In this study, concepts, procedures and parameters of the Bailey Method, that is strongly based on sieves and aggregate sizes adopted in the USA, were applied in the European perspective. To this aim, two sets of asphalt mixtures were designed applying the Bailey Method. The study shows that the European practice for aggregate grading design allows the application of the Bailey Method criteria confirming the validity of its basic principles.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/81959

A strategic laboratory approach for the performance investigation of geogrids in flexible pavements
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Ferrotti, Gilda; Canestrari, Francesco; Virgili, Amedeo; Grilli, A.
Classificazione: 1 Contributo su Rivista
Abstract: ABSTRACT: Nowadays, the increasing request in terms of road transport makes maintenance and rehabilitation of road infrastructures key tasks for road engineering. In recent years, numerous products/materials have been introduced on the market and can be used in combination or singly in order to extend pavement life and guarantee high performance. Among them, geosynthetics can play different roles in pavement structures, such as draining, reinforcement, filtering, separation, protection, and proofing. This research focuses on the validation of a strategic laboratory approach for the study of the mechanical performance of reinforced systems used in flexible pavements, combining repeated loading cycles in a four-point bending configuration with interlayer shear tests. This method can be used in further research analysis to compare unreinforced and reinforced double-layered systems. The results obtained in this investigation showed that the fiberglass grid used provides a relevant contribution to the performance of the asphalt concrete system studied.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/71045

Pavimentazioni Rinforzate - Progetto Pilota nella Provincia Autonoma di Bolzano
STRADE & AUTOSTRADE
Autore/i: Bocci, Maurizio; Canestrari, Francesco; Ferrotti, Gilda; Pasquini, Emiliano
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/54829

Acoustic characterization of Asphalt Rubber mixtures in Italy
INTERNOISE 2010 - Proceedings of the 39th International Congress on Noise Control Engineering
Autore/i: Pasquini, Emiliano; Canestrari, Francesco; Ferrotti, Gilda; Santagata, Felice Ausilio; Serpilli, F.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Pavements that produce less noise at the tire/pavement interface represent an important strategic solution necessary to minimize traffic acoustic impact. Several international studies showed encouraging results in traffic noise reduction using Asphalt Rubber (AR) mixtures. The Authors present results of an Italian experience that investigates the acoustic properties of AR mixtures, paved on existing roads as wearing course, by means of in situ noise measurements carried out at different stages. These materials were studied through laboratory tests for sound absorption evaluation. Results also evaluate the properties of AR mixtures in limiting traffic noise comparing them with other typical asphalt concretes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/42350

Experimental study on cold micro-surfacing with crumb rubber
Proceedings of the 6th Int. Conf. on Maintenance and Rehabilitation of Pavements and Technological Control - MAIREPAV6
Autore/i: Canestrari, Francesco; Pasquini, Emiliano; Ferrotti, Gilda; Riviera, P.
Editore: Ezio Santagata
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Nowadays environmental sustainability is one of the main issues which developed countries have to deal with. The aim of this study was to evaluate the possibility of adding crumb rubber coming from reclaimed tires as a dry ingredient in cold micro-surfacing mixes. In fact, these innovative cold bituminous mixtures could allow the recycling of waste tires and reduce tire/road noise. In this paper, the mechanical performance of cold microsurfacing mixes prepared with crumb rubber added in different dosages and sizes was investigated in the laboratory by means of the cohesion test, the modified British wheel tracking test and an innovative test method, expressly designed for thin cold mixes. Moreover, a cold micro-surfacing with the dry addition of crumb rubber was also laid down on a very busy urban road. Acoustic and skid measurements were carried out both in situ and in the laboratory in order to evaluate the functional properties of this new road material.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/42345

RILEM Interlaboratory Test on Interlayer Bonding of Asphalt Pavements
Advanced Testing and Characterization on Bituminous Materials
Autore/i: Piber, H; Canestrari, Francesco; Ferrotti, Gilda; Lu, X; Millien, A; Partl, M. N.; Petit, C; PHELIPOT MARDELE', A; Raab, C.
Editore: Taylor & Francis Group
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The RILEM TG 4 organized an interlaboratory test in order to compare the different test procedures to assess the interlayer bonding properties of asphalt pavement. The pavement was composed of two layers. Three different interface conditions were chosen. The first pavement was laid without interface treatment and the others with two different types of emulsion. 14 laboratories from 11 countries participated in this study and carried out shear or torque tests on 1400 cores. The maximum shear or torque load and the corresponding displacement were measured and the shear or torque stress was calculated as a function of the following parameters: diameter, test temperature, test speed, stress applied normal to the interface and age of the specimen. This paper presents the results of this study in terms of precision and correlations regarding the parameters
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/42343

Laboratory performance-based evaluation of cold bituminous mixtures for patching applications
Proceedings of the 6th Int. Conf. on Maintenance and Rehabilitation of Pavements and Technological Control
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Grilli, A; Barbati, S.
Editore: Ezio Santagata
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT: A flexible pavement under repeated loading cycles and environmental conditions is subjected to progressive deterioration and aging. For local roads, two of the main surface distresses on bituminous pavement are raveling and localized depression which lead rapidly to potholes. Since these localized-hazardous failures compromise safety and pavement serviceability, they must be repaired as soon as they occur. Usually, the temporary rehabilitation of local roads subjected to potholes is managed by public administration as emergency treatment or planned maintenance, by using cold bituminous mixtures that are often not able to guarantee a long-lasting pavement repair. In this sense, innovative and high-performance cold bituminous mixtures have been recently optimized, replacing the traditionally used bituminous emulsion with special bitumen, resins, anti-stripping agents and several additional ingredients. The aim of this research project was to improve the knowledge of these products used for patching operations and the proposal of an overall testing protocol able to characterize highperformance cold bituminous mixtures using test procedures and parameters similar to those used for hot mix asphalt. The results showed that the tested material guarantees, under specific curing time and test temperature, higher performance than traditional cold bituminous mixtures and that the proposed test procedure can be used for the evaluation of such high-performance products.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/42346

Interlayer bonding design of porous asphalt course interface
Proceedings of the Sixth International Conference on Maintenance and Rehabilitation of Pavements and Technological Control, MAIREPAV6
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Graziani, Andrea; Baglieri, O.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT: Interlayer bonding affects performance of asphalt concrete pavements. In order to guarantee good bonding, tack coats are frequently applied at various interfaces. Interlayer bonding design consists in the determination of the optimum tack coat rate and the ASTRA (Ancona Shear Testing Research and Analysis) test method can be used for this purpose. In this study, the tack coat design of the interface between an existing porous asphalt and a newly laid open graded course was developed. In order to check whether the two porous layers are independent or behave as a Twinlay, the drainability of the resulting double-layered system was also investigated. The ASTRA tests showed that acceptable interlayer bonding results can be obtained for each emulsion rate studied but higher tack coat rates mitigate the scatter of the results. In terms of drainability, the porosity of the existing layer does not increase the drainage characteristics of the double-layered system, for each interface treatment considered.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/50262

Statistical investigation of two different interlayer shear test methods
THE INTERNATIONAL JOURNAL “MATERIALS AND STRUCTURES
Autore/i: Santagata, Felice Ausilio; Ferrotti, Gilda; M. N., Partl; Canestrari, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The performance of multi-layered pavement systems strongly depends on interlayer bonding. In order to evaluate this parameter, some countries have developed their own test method. However, different devices generally provide different results due to the test conditions. In this article, the statistical investigation of two interlayer shear test methods is shown considering different asphalt materials and different specimen preparation techniques. Both test methods provided comparable results showing the same ranking in interlayer shear stress for different test conditions and the same level of precision in terms of scatter of the results. Moreover, the repeatability limit was found to be dependent on the test method, the pavement material and the compaction technique. It is worth noting that this extensive experimental investigation paves the way for the incoming European Standardization process involving the two shear test methods.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/31459

Layer Characteristics Affecting Interlayer Shear Resistance in Flexible Pavements
JOURNAL OF THE ASSOCIATION OF ASPHALT PAVING TECHNOLOGISTS
Autore/i: Santagata, Felice Ausilio; Parti, M. N.; Ferrotti, Gilda; Canestrari, Francesco; Flisch, A.
Classificazione: 1 Contributo su Rivista
Abstract: The evaluation of interlayer shear resistance is important to better understand how multi-layered pavements behave under traffic conditions. This paper focuses on the characterization of the interlayer shear behavior in flexible pavements through experimental investigation and analysis of two parameters that affect interlayer bonding: the influence of air void content of the two mixes in contact and the contact surface roughness of double-layered asphalt concrete specimens. Two different shear test devices (LPDS and ASTRA equipments) were used to evaluate interlayer resistance, whereas air void content and roughness characteristics at the interface were measured by using both traditional and innovative techniques. In particular, a non-destructive method, the X-ray Computer Tomography (CT), was used to investigate interlayer air void content and interlayer roughness after compaction of the upper layer. The results were able to show that air void content influences interlayer shear resistance in a non-linear way. As far as contact surface roughness is concerned, profile comb, laser profilometer and X-ray CT were used and further elaborated with advanced techniques such as fractal theory and spectral analysis. The results showed how higher macro-texture leads to an increase in LPDS and ASTRA interlayer shear resistance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/31455

Experimental characterization of transparent synthetic binder mixes reinforced with cellulose fibres
4th International SIIV congress
Autore/i: F. A., Santagata; Canestrari, Francesco; Ferrotti, Gilda; Graziani, Andrea
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The use of synthetic binders in wearing course mixes allows to integrate road pavements into urban surroundings. In fact, the mixes prepared with this binder mitigate the visual impact that common asphalt materials produce, allowing a pavement coloration depending on the aggregate dyes to be obtained. In this paper, the characterization of open graded mixes prepared with a synthetic binder, reinforced or not with cellulose fibres, was performed. In particular, nine mixes, with different binder and cellulose fibre contents, were investigated through several laboratory tests to find the ‘optimum’ mix in terms of both mechanical performance and durability. The study of all mixes was performed in two steps. In the first step, traditional tests were carried out: Marshall, Indirect Tensile and Cantabro tests. Moreover, to investigate the water effect on these open graded mixes, the traditional tests were also performed on specimens immersed in water for 15 days, and the results were compared. In the second step, the same nine mixes were investigated in terms of rutting behaviour by using Wheel Tracker Machine, and stiffness modulus and fatigue strength through Nottingham Asphalt Tester (NAT). Finally, the comparison with a traditional open graded mix (with SBS hard bitumen) was performed showing higher laboratory performance for the synthetic binder mix. This paper shows that specific synthetic binder and cellulose fibre contents provide an ‘optimum’ open graded mix.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/52988

Experimental characterization of interlayer shear resistance in flexible pavements
Autore/i: Ferrotti, Gilda
Editore: Università Politecnica delle Marche
Classificazione: 8 Tesi di dottorato
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/242619

Mechanical characterization of environmentally friendly mixtures
Advanced Characterisation of Pavement and Soil Engineering Materials
Autore/i: Bocci, Maurizio; Canestrari, Francesco; Ferrotti, Gilda; Pasquini, Emiliano
Editore: A. Loizos, T. Scarpas, I: Al-Qadi
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Nowadays, road traffic is the main cause of urban pollution. Owing to the primary importance of this problem two different environmentally friendly mixtures were considered: the first to reduce traffic noise and the second to mitigate atmospheric pollution. The anti-noise mixture is a dense-graded HMA in which 27% volume of mineral aggregates was replaced with expanded clay. The second mixture, which should mitigate air pollution, is an open-graded asphalt concrete partially filled with a cement mortar containing a photocatalytic agent (titanium dioxide). In order to properly use these mixes for road applications the evaluation of specific mechanical performance is required. In particular, the Authors show the laboratory characterization of the mixtures in terms of stiffness modulus, fatigue life and rutting comparing them with dense-graded and open-graded wearing courses, respectively.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53843

Verifica prestazionale di materiali impiegati per la realizzazione di segnaletiche orizzontali
16° CONVEGNO NAZIONALE SIIV
Autore/i: F., Santagata; Canestrari, Francesco; Ferrotti, Gilda
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Road marking functional retraining is a maintenance operation that more and more often involves road pavement management. These maintenance operations, extended to the whole road network, become very expensive both for direct costs and for indirect costs due to traffic slowing down. Road marking noticeably influences road safety. On the subject, some studies show that the decrease of accident risk is strongly connected with typical road marking characteristics as right visibility (day-time and night-time), suitable adhesion level and durability compatible with road network management. The Standard UNI EN 1436/98, according to the provisions of the Italian Road Code, fixes the principles to control road marking performances through the service life concept. It mainly depends on the frequency of vehicular passing, on the traffic variety, on the pavement characteristics and on the particular climatic conditions. However, it ignores engineering aspects tightly connected with the material life. In this sense, the above-mentioned Italian Road Code and the relative Regulations underline the need to characterize road marking as a material and not only as a “furniture”. The present work shows the results of an experimental study carried out on a trial section. The characteristics of 6 different materials (3 solvent paints and 3 waterborne paints) were studied to evaluate both photometrical and adhesion properties employing the Standard provisions. Through direct comparisons and periodic monitoring, it has been possible to estimate, on two different pavement surfaces, the material life and the effects of environmental conditions on required performances.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53832

Influence of contact surface roughness on interlayer shear resistance
Proceedings, 10th International Conference On Asphalt Pavements ISAP
Autore/i: Partl, M. N.; Canestrari, Francesco; Ferrotti, Gilda; Santagata, F. A.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Regarding performance of multi-layered asphalt pavement systems, interlayer bonding has an important role because it considerably influences stress and strain distribution in the pavement. Interlayer shear resistance may depend on various factors such as type and presence of tack-coat, maximum aggregate size and air void content of the two mixes in contact, as well as roughness conditions at the interface. This study, which is part of an ongoing research project, focuses primarily on the possible relationship between interlayer shear resistance and lower layer surface roughness of double-layered asphalt concrete specimens. In addition, the study deals with the comparison of different methods to evaluate this contact surface roughness. Before placing the upper layer, two different methods were applied to determine surface profiles: a laser profilometer and a profile comb. The obtained profiles were used to perform MPD (Mean Profile Depth) and fractal dimension evaluations. Moreover, the lower layer surface roughness was evaluated with the traditional sand patch method. Each technique was used to seek a relationship between the contact surface roughness and the interlayer shear resistance measured by both ASTRA (Ancona Shear Testing Research and Analysis) test device and LPDS (Layer-Parallel Direct Shear) test device. The results show that greater contact surface roughness leads to an increase in ASTRA and LPDS interlayer shear resistance in different proportions for MPD, fractal dimension and sand patch method roughness evaluation.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/53838

Repeatability of Interlayer Shear Resistance determined With Two Test Procedure
Convegno Internazionale SIIV, Bari 2005
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; Partl, M; Santagata, F. A.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Interlayer bonding significantly influences the performance of multi-layered pavement systems. To correctly know how this bonding modifies the interlayer mechanical performance, theoretical and experimental projects are currently in progress in many countries. However, different equipments generally provide different results because these results are obtained under different test conditions in terms of applied stress and strain, rate of displacement, specimen size and specimen confinement. Since in European Standards there is a normative gap regarding interlayer resistance tests, in Italy a draft of a standard is currently under development based on a laboratory direct shear device called ASTRA (Ancona Shear Testing Research and Analysis). In the present paper, the repeatability of ASTRA test method is studied by analyzing the results obtained in two experimental investigations. In the first investigation, specimens prepared with the same material and the same compactor were tested with ASTRA test method and with another shear test method, the LPDS (Layer-Parallel Direct Shear), which is compatible with Swiss Standards (Schweizer Norm SN 671961, 2000). In the second investigation, the first series of ASTRA results were compared with repeatability results obtained by using different materials and different compaction methods for the double-layered specimens. The study shows that the two shear test equipments provide the same precision level in terms of scatter of the results. Moreover, the ASTRA investigation shows that the repeatability depends not only on the test method but also on the pavement material and compaction method. This study allows supporting Italian standardization of interlayer shear resistance testing and, at the same time, it shows that it is necessary to further investigate different materials and different compaction methods to improve the knowledge on repeatability.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/43896

Advanced testing and characterization of interlayer shear resistance
TRANSPORTATION RESEARCH RECORD
Autore/i: Canestrari, Francesco; Ferrotti, Gilda; M., Partl; E., Santagata
Classificazione: 1 Contributo su Rivista
Abstract: The performance of multi-layered pavement systems strongly depends on interlayer bonding. Thus, to guarantee good bonding, during pavement construction or overlay, tack coats (also indicated as bond coats) are usually applied at the various interfaces. The effectiveness of the tack coat can be assessed by making use of several devices which are arranged by different laboratories to evaluate interlayer shear resistance. The paper shows how interlayer shear resistance may be evaluated through ASTRA device. The ASTRA results, expressed in terms of maximum interlayer shear stress (peak), highlight the effects of various influence parameters such as type of interface treatment, curing time, procedure of specimen preparation, temperature, applied normal load. Moreover, the paper compares the peak results obtained by two different shear test devices: the ASTRA tester designed and developed in the Università Politecnica delle Marche (Italy) and the LPDS tester created by EMPA (Swiss Federal Laboratories for Materials Testing and Research). Both test methods provide different but comparable results showing the same ranking of shear resistance for different interface treatments.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/31303