Stone Mastic Asphalt Mixtures Research Articles

Coal-derived conductive pavement for winter de-icing: prototype, modeling, and simulation

Existing pavement de-icing methods result in high installation and maintenance costs, traffic delays, excessive weariness and corrosion, and negative environmental and safety impacts. To overcome these challenges, this paper presents an innovative pathway to design and construct smart self-heating pavements using a low-cost coal-char bearing asphalt material. The conductive asphalt incorporates coal char, i.e., a key byproduct of the coal pyrolysis process, into the Stone Mastic Asphalt (SMA) mixture. This asphalt containing coal-derived solid carbon exhibits highly tailorable electrical conductivity, satisfactory mechanical and thermophysical properties, and superior cost-efficiency as compared to other conductive pavement materials. The de-icing performance was also demonstrated by laboratory experiments on a bench-scale prototype. Furthermore, an efficient thermal network model was developed and validated by experiments to investigate the transient thermal behavior and energy performance of the Ohmic heating pavement system. The whole-year energy simulation case studies were conducted on a bridge pavement with an annual energy use of 24.6–––1444.8 kWh/m2, showcasing its potential in field applications across cool humid, cold humid, and subarctic/arctic climate zones

Performance evaluation of stone mastic asphalt reinforced with shredded waste E-cigarette butts

The recycling of waste materials in asphalt pavements is pivotal for advancing the road industry, offering numerous environmental, economic, and societal benefits. This study explores the recycling potential of waste electronic cigarette butts (E-CBs) within stone mastic asphalt (SMA) mixtures, serving as a substitute for cellulose fibres and enhancing mechanical performance. Considering the critical role of fibre size in asphalt mixtures, two different E-CB shredding sizes (10 and 15 mm) were selected for examination. Additionally, the influence of the plastic component within E-CBs was investigated. The stabilizing effects of using the shredded E-CBs were evaluated via drain-down tests, followed by a series of standard laboratory tests aimed at assessing physical and mechanical properties. Results demonstrate acceptable drain-down properties, volumetric properties, and moisture susceptibility for the use of all four shredded E-CBs. Among the four mixtures incorporating the waste fibres, the utilization of 15 mm shredded E-CBs without plastic constituents yielded the highest values for indirect tensile strength (ITS) and indirect tensile stiffness modulus (ITSM), coupled with excellent water susceptibility and rutting performance. It can be considered a promising alternative to the traditional cellulose fibre. Larger shredded E-CBs exhibited potential for improving mechanical properties, encompassing cohesion, stiffness modulus, and rutting resistance. Although plastic inclusion can enhance rutting resistance, the higher thermal susceptibility associated with plastic warrants careful consideration. Future research may focus on investigating the fatigue and low-temperature cracking properties, as well as the reinforcing mechanisms of shredded E-CBs in asphalt mixtures using micro-characterization techniques.

Utilization of steel slag as coarse aggregate and filler in stone mastic asphalt (SMA) mixture: Engineering performance, environmental impact and economic benefits analysis

The unquantified environmental impact and economic benefits of steel slag based asphalt mixture, as well as the difficulty in directly utilizing steel slag fine aggregate (SSFA) due to solidification, limit the utilization of steel slag in asphalt mixture. This research proposed an innovative method of using steel slag coarse aggregate (SSCA) and steel slag powder (SSP) filler prepared by grinding solidified SSFA to replace ordinary natural resources to prepare stone mastic asphalt (SMA) mixture. The feasibility of the proposed utilization method of steel slag was determined based on the analysis results of main engineering performance, environmental impact and economic benefits of steel slag SMA mixture (SSSM). The ordinary SMA mixture (OSM) was functioned as a control group. The investigated main engineering performance included fatigue performance, moisture stability, high-temperature deformation resistance and low-temperature crack resistance. Environmental impact was evaluated based on the life cycle assessment (LCA) method, and the relationship between the transportation distance of steel slag, common basalt and the emission characteristics was deeply analyzed. In addition, economic benefits were determined based on the cost calculation results. Results showed that SSSM was superior to OSM in terms of these main engineering performance. The emissions from SMA mixtures increased with the extension of transportation distance of steel slag or basalt. From the perspective of reducing emissions, choosing steel slag aggregate had advantages when the transportation distance was less than 365 km, otherwise, it was recommended to choose basalt. Under three different transportation distances (short, medium and long distance transportation), the introduction of steel slag in SMA mixture reduced the greenhouse gas emissions by 1.1%–8.6%, of which the raw material production stage contributed the most. Furthermore, SSSM exhibited higher economic benefits, with a functional unit of SSSM pavement saving the cost by 14.4%–19.8%. Therefore, using steel slag as a substitute for coarse aggregate and filler in SMA mixture can promote the reuse of solidified SSFA, reduce the environmental impact and total cost of all stages of constructing SMA pavement.

Effect of Gradation Variation on Mixture Properties in Stone Mastic Asphalt Mixtures with Carbon Fiber and Hybrid Aggregate

Due to advantages like abrasion resistance, increased operating and service life, high coarse aggregate content and high resistance to deformation, increased fatigue life, and others, stone mastic asphalt (SMA) mixtures have recently become a popular asphalt pavement type in road sections such as highways, tunnels, and bridges. There hasn't been much research on the topic, despite the fact that gradation significantly affects the performance of SMA combinations. In this study, the experimental findings of three distinct gradations of SMA mixtures with hybrid materials (basalt coarse aggregate, limestone fine aggregate) and carbon fiber were compared. As a result, it was concluded that the hybrid aggregate used with carbon fiber, maximum aggregate size, and coarse aggregate % had a positive impact SMA mixtures.

Investigation of Using Ulexite as a Filler in Various Combinations in Stone Mastic Asphalt Mixtures

Investigation of Using Ulexite as a Filler in Various Combinations in Stone Mastic Asphalt Mixtures

Research on skid-resistance durability of high viscosity modified asphalt mixture by accelerated abrasion test

To evaluate influence of external environment and material composition on skid-resistance durability of high viscosity modified asphalt (HVMA) mixture, the accelerated abrasion test was selected to simulate decay of skid resistance for asphalt mixture by setting different test conditions. The influence of aggregate gradation, asphalt type, ambient humidity and overload on skid-resistance durability of asphalt mixture was discussed, and the significant effect of selected factors on skid-resistance durability of asphalt mixture was revealed. The results show that the skid-resistance durability of SMA-13 (Stone Mastic Asphalt) mixture is better than OGFC-13(Open Graded Friction Course) and PA-13 (Porous Asphalt) mixture under different conditions, and attenuation rate of different indexes of SMA-13 mixture is 1.6–2.2% and 0.8–2.1% lower than compared with OGFC-13 and PA-13 mixture. The attenuation rate of texture depth for asphalt mixture is closely related to aggregate gradation and asphalt, but the attenuation rate of british pendulum number for asphalt mixture with the same mineral aggregate is only significantly affected by the asphalt. The skid resistance of SMA-13 and PA-13 mixture is improved slightly by addition of high viscosity modified asphalt. The attenuation rate of texture depth of SMA-13 and PA-13 mixture with HVMA is reduced about 0.6–3.0% and 2.2–4.2% than SBS modified asphalt, but the attenuation rate of british pendulum number of above mixtures is increased about 1.2–1.6% and 0.3–1.7%. The skid-resistance durability of asphalt mixture with TPS (TAFPACK-Super) and SINOTPS high viscosity agent is better than HVA (High viscosity additive). The skid-resistance durability of asphalt mixture based on texture depth is improved under wet condition. However, the skid-resistance durability of asphalt mixture for british pendulum number gets worse due to water intrusion. The skid-resistance durability of asphalt mixture is rapidly decreased under overload condition. The influence of overload and SBS modified asphalt on skid-resistance durability of asphalt mixture is higher than ambient humidity and HVMA. This paper will provide foundation for high viscosity modified asphalt applied in asphalt pavement.

Comparison of the moisture resistance of a steel-slag stone mastic asphalt mixture modified with Ca(OH)2

Stone mastic asphalt is a type of hot mix asphalt that requires much coarse aggregate, so substitution waste aggregate, such as steel slag, will be an economic reason. The problem is that there are still many things that have not been consistent in various studies related to the moisture resistance of steel slag. The study aimed to compare the effect of Ca(OH)2 on the moisture resistance of the steel-slag stone mastic asphalt mixture and to determine the optimal Ca(OH)2 dosage for improving the mixture resistance. This study employs basalt aggregate, steel slag from Krakatau Steel Company, 60/70 penetration asphalt, a stabilizing substance made of bamboo fiber, and Ca(OH)2. The Texas boiling and the static immersed methods are used to test the adhesion on a loose mixture. The retained Marshall stability and indirect tensile strength are used to test the adhesion on the compacted mix. Testing result of Krakatau steel slag shows that steel slag has a much higher Fe2O3 content than steel slag in general and has low water absorption; a poor affinity for asphalt results from this. The result of the Texas boiling method showed a decrease in the percentage adhesion value between steel slag and asphalt compared to natural basalt aggregates and asphalt. Marshall Stability Ratio and Tensile Strength Ratio increased after mixing the asphalt with Ca(OH)2. Marshall test results show decreased stability in mixtures with steel slag substitution. Adding Ca(OH)2 increased stability and resistance to moisture significantly. This indicated that Ca(OH)2 enhances moisture resistance on stone mastic asphalt with modified steel slag. Stability, Marshall stability ratio, indirect tensile strength ratio, particle loss, and Texas boiling test significantly improved with adding Ca(OH)2

ЩЕБЕНЕВО-МАСТИКОВІ АСФАЛЬТОБЕТОННІ СУМІШІ – СКЛАДНИКИ, СКЛАД, ПРОЄКТУВАННЯ ТА ВИМОГИ

Introduction. Stone mastic asphalt mixtures are probably the most popular road construction material for paving roads not only in Ukraine but also around the world. State construction standards provide for the mandatory use of SMA mixtures for paving roads of category I, and it is also possible to use SMA mixtures for paving roads of II – III categories. Problem Statement. For the first time, the properties of SMA mixtures, as well as stone mastic asphalt concrete, were standardized in DSTU B V.2.7-127 in 2016. Since then, two amendments to this standard have been developed (2012 and 2014), its revision has been carried out (2015), an amendment to the revised standard has been developed (2019) and another revision is currently underway. Thus, we can conclude that there is a significant interest in these road construction materials. In 2018, as part of its European integration efforts, Ukraine adopted DSTU EN 13108-5 which sets harmonized requirements for SMA mixtures and SMA used in the European Union. However, this standard has not yet been implemented in Ukraine, which is due to the lack of specific requirements for SMA mixtures, SMA, as well as their components depending on the field of application. In the literature sources, it is almost impossible to find information on the establishment of requirements for SMA mixtures and SMA, as well as their components during the development of DSTU B V.2.7-127 with regard to climatic conditions and traffic load, which is obviously due to the significant affinity of this standard with the Soviet one. Therefore, to be able to establish national requirements for SMA mixtures and SMA in accordance with DSTU EN 13108-5, it is advisable to perform a detailed analysis of the literature sources on this issue.

Improvement of pavement engineering properties with calcium carbide residue (CCR) as filler in Stone Mastic Asphalt

Characteristics of pavement material are crucial factors in improving the stability and durability of asphalt pavement due to the poor performance of traditional asphalts. Reusing industrial waste in asphalt concrete production can address these concerns, reduce environmental problems and preserve resources. There have been few studies on the effects of using industrial waste materials on Stone Mastic Asphalt (SMA) properties. This paper examines the impact of Calcium Carbide Residue (CCR) as a filler in SMA. The study evaluates control samples, those with Rock Powder (RP) and Ordinary Portland Cement (OPC) filler, and those with CCR using Marshall stability (MS) and Indirect Tensile Strength (ITSdry and ITSsat) tests. Results show positive effects of CCR and RP on asphalt sample strength. The highest MS, MQ, and TSR values were observed in samples containing CCR80 %+RP20 %. These indices increased 45 %, 35 %, and 51 %, respectively, compared to control samples. The alkaline CCR material forms strong bonds with acidic bitumen, producing asphalt more resistant by 97 % compared to control samples. SMA modified with CCR + RP was also found to be less sensitive to water damage than traditional SMA with RP or OPC filler. The rough texture of CCR may positively affect the strength and durability of asphalt mixtures against moisture damage. Using CCR as a filler in SMA can enhance pavement engineering properties, reduce production costs and environmental problems, and develop sustainable asphalt mixtures for practical application. The main novelty of this research is the use of CCR and RP combination in SMA mixtures.

Experimental investigation on the preparation and surface treatment of biomass fibers for stone mastic asphalt mixtures modification

With the sustainable development of infrastructure construction materials, the use of renewable biomass resources in asphalt mixtures could contribute to better sustainability. The bamboo fibers and corn straw fibers with lengths ranging from 1.5 to 12 mm were produced in the laboratory through the proposed crushing, steaming, and grinding processes. A surface treatment with the phenolic resin copolymer modifier was utilized to reconstruct the micro-surface of biomass fibers. The surface treatment effectively reduced the oil absorption multiplier and mass loss of proposed biomass fibers by about 0.6 and 2 %, respectively. The FI-IR absorption peak and change of micromorphology also validated the effective surface reconstructive. Afterward, the virgin asphalt (70#) mixtures and SBS-modified asphalt mixtures with/without biomass fibers were produced for road performance tests and fatigue resistance tests. The results showed that the proposed biomass fibers contributed to about 20 % to 30 % improvement in the high-temperature performance, while the low-temperature cracking resistance was also obviously increased. In addition, the moisture damage resistance and fatigue life were also improved after the addition of biomass fiber modifier, in which the residual stability and tensile strength ratio were increased by about 9 % and 6 % by comparing that with fibreless mixtures, respectively. By comparing the effect of different types and lengths of fiber modifiers, the long bamboo fiber with surface treatment represented the optimized strengthening efficiency. The enhancement mechanism of proposed biomass fiber modifiers was revealed through the microstructure observation. The feasibility of using proposed biomass fibers with surface treatment for producing high-performance SMA has been verified, which can be utilized in the field application for replacing the lignin fiber modifiers for achieving better sustainability.

The use of natural fibers in stone mastic asphalt mixtures: a review of the literature

The use of natural fibers in stone mastic asphalt mixtures: a review of the literature

Engineering characterization and environmental analysis of natural rubber latex modified asphalt mixture

Natural Rubber Latex (NRL) has attracted considerable interest as a resource for renewable paving materials due to its potential to lessen environmental impact. In order to gain a thorough understanding of the performance of NRL, this study evaluated the mechanical properties and environmental impact of Stone Mastic Asphalt (SMA) mixtures with a 6.6% binder content, 5% air voids content, and 5% NRL by weight of binder. The performance of this NRL asphalt mixture was compared to a control asphalt mixture using a commercially available polymer modified Styrene Butadiene Styrene (SBS) binder. The performance of the asphalt mixtures, such as their tensile strength, stiffness modulus, and resistance to fatigue and rutting, as well as their Global Warming Potential (GWP) impact, were studied. The results indicate that the addition of NRL increased tensile strength, stiffness modulus, and fatigue life in comparison to a conventional, unmodified asphalt mixture but had slightly lower values in comparison to the SBS mixture. Moreover, in terms of environmental concern, life-cycle assessment reveals that NRL-modified mixtures are more sustainable than SBS-modified mixtures in terms of GWP value.

Laboratory investigation on the use of wood waste fibres in SMA mixtures

This research investigates whether wood waste fibres, produced from the leftovers from the manufacture of wood panels for furniture, can be used to stabilize the binder (to absorb the excess binder) in stone mastic asphalt (SMA) mixtures rather than being disposed of in landfill or incinerated. In this research, SMA 8 S mixtures with different amounts (0.3%, 0.5%, 0.7%, 0.9% and 1.1%) of wood waste fibres were analysed. The reference mixture with 0.3% cellulose fibres was also produced. The ability of wood waste fibres to absorb the binder was determined by the binder drain down test, and the particle loss test was used as a primary indicator to evaluate the performance of the mixture. The influence of wood waste fibres on the performance of SMA mixtures was comprehensively evaluated with two amounts of wood waste fibres in terms of air void content, water sensitivity, stiffness, resistance to rutting, and resistance to fatigue. Research showed that 0.7% of the wood waste fibres is an optimal amount. It ensures both binder absorption and SMA 8 S mixture performance equivalent to that with 0.3% cellulose fibres.

Experimental Study on the Cracking Resistance of Asphalt Mixture with Different Degrees of Aging

The cracking resistance of asphalt mixture is a non-negligible issue. However, the cracking resistance evolution law, motivated by two factors (thermos-oxidative aging degree and test temperature), is not yet well understood. The aim of this investigation is to gain more insight into the effect of thermos-oxidative aging and test temperature on the cracking resistance of asphalt mixture. Asphalt mixture (AC-13) and stone mastic asphalt mixture (SMA-13) were selected and exposed to different thermo-oxidative aging degrees (unaging (UA); short-term thermo-oxidative aging (STOA); long-term thermo-oxidative aging for 2/5/8 days (LTOA2d/LTOA5d/LTOA8d)). A direct tension test at different test temperatures (10 °C, 20 °C, 30 °C, 40 °C) was adopted to obtain their stress–strain curves and evaluation indexes (tensile strength, ultimate strain, pre-peak strain energy density, and post-peak strain energy density). The comprehensive index-cracking resistance index (CRI) was established by the entropy weight method combined with the technique to order preference by similarity to ideal solution (TOPSIS) method and the corresponding aging coefficient was determined. The results showed that STOA can increase the aging coefficient of asphalt mixture, thereby boosting the cracking resistance. Additionally, the effect can be weakened by elevations in the test temperature. Meanwhile, LTOA can decrease the aging coefficient and thereby weaken the cracking resistance. This effect becomes more prominent with elevations in the test temperature. SMA-13 possesses a superior cracking resistance to AC-13, with a gap in CRI value of 3–69%, regardless of the aging degree and test temperature. A good relationship exists between the aging coefficient and the two factors (aging degree and test temperature).

INVESTIGATION OF THE MECHANICAL PERFORMANCE OF STONE MASTIC ASPHALT MIXTURES MODIFIED BY RECYCLED WASTE POLYMERS

The usage of polymer-modified asphalt binders has increased as a result of the significant increase in the number of conventional cars operating on Iraqi roads in recent years. This has resulted in increased strains being placed on pavement structures and materials. Global exploration has focused on the development of stabilizing Stone Mastic Asphalt mixtures for improved pavement behavior. Numerous effective efforts were made to stabilize stone mastic asphalt mixes with polymers and fibers. Iraq produces a considerable amount of waste polymer materials each year. Usually, they are sent to landfills for disposal. These wastes are dumped, occupying a sizable portion of landfill space and creating various serious environmental issues. The study focuses on how waste polymer additions, such as recycled plastic bottles, shopping boxes, and tire crumb rubber, affect the mechanical performance and durability of stone mastic asphalt mixtures. The mechanical performance attributes were assessed. It is evident from the findings that the drain-down amounts were within the permissible requirement range. The findings also showed that the indirect tensile strength, Marshall Stability, moisture damage resistance, and resistance for permanent deformation of stone mastic asphalt mixtures have all increased as a result of the use of waste polymer components. The recycled polymer-modified mixes are the combinations that are most resistant to rutting, according to the results of the repeated load axial creep tests. Iraq may have new options to employ the significant volumes of recycled polymers that are becoming accessible as a result of recycling waste polymers.

Experimental study on the effects of modification with nanoclay on the properties of an SMA mixture

The modification of bitumens with NM has shown results in the improvement of binder properties, in particular thermal susceptibility. This article aims to present a study to demonstrate the effects of modifying a bituminous mixture (BM) of the Stone Mastic Asphalt (SMA) type with nanoclay. The nanoclay used was of the hydrophilic bentonite type. The modification of the bitumen was carried out by introducing and dispersing in conventional bitumen a 35/50 amount of nanoclay corresponding to 4% of the weight of the modified binder. The bitumens, conventional and nanomodified, were characterized by determining penetration, ring and ball softening temperature and viscosity. In the subsequent BM, to investigate the influence of the nanomodification, tests of permanent deformation (PD), modulus of deformability, resistance to fatigue and sensitivity to water were carried out. The results obtained showed that the nanomodified SMA mixture showed better resistance to fatigue, increase in indirect tensile strength (ITS), less sensitivity to and better resistance to PD.

Characterization of Interlayer Bonding Mechanism Based on Interface Morphology in Double-Layered Asphalt Systems

The mechanism of interlayer bonding and its relationship with interface morphology in asphalt pavement is not well understood yet. This study aims at investigating the effect of interface morphology on the interlayer bonding performance of double-layered asphalt systems. Four double-layered asphalt systems were prepared with rubberized asphalt concrete (RAC), asphalt concrete (AC), and stone mastic asphalt (SMA) mixtures. To test the influence of different interlayer treatments, three conditions were studied: styrene-butadiene-styrene (SBS)-modified asphalt gravel seal (GS) coat (SBS-GS), rubber-modified asphalt gravel seal coat (RA-GS), and fiber-reinforced rubber–modified asphalt gravel seal coat (FR-GS). The influence of surface type and interface treatment on interface morphology and bonding properties were compared and analyzed using a series of indoor interlayer shear bonding tests under three temperature conditions in two phases. In addition, based on the three-dimensional (3D) scanning and reconstruction technique, the morphology of the nondestructively separated interface of double-layered systems with no interlayer treatment was obtained, and the mechanism of the influence of the interface morphology on the interlayer shear strength was analyzed in depth. The results showed that double-layered systems exhibited different macrotexture and roughness characteristics at interlayer surfaces, creating distinct interface morphology properties for each system type. Consequently, the interlayer bonding strength and performance of double-layered asphalt systems were affected accordingly. In this respect, the order of the interlayer shear strength of double-layered systems with different interlayer treatments at different temperatures ranked as RAC-13/RAC-20 > SMA-13/RAC-20 > SMA-13/AC-20 > AC-13/AC-20. It was demonstrated that the proposed interface area ratio (K) can be used for the characterization of the interface morphology and reflect the interlayer bonding state. Moreover, it was found that the interlayer treatment could influence the interface morphology to a certain extent and change the effective bonding between layers. As a result, the order of interlayer shear strength of different interlayer bonding treatments ranked as FR-GS> RA-GS > SBS-GS. Finally, aggregate gradation of the mixtures could also affect the morphological characteristics of the interface.

Evaluation of fracture behavior of stone mastic asphalt (SMA) containing recycled materials under different loading modes at low temperatures

Using natural materials (including aggregates and bitumen) in the asphalt paving industry causes significant and irreparable damage to the environment annually. Utilizing waste materials in producing asphalt pavements can be a suitable solution to reduce such damages. Therefore, this paper studied the impacts of recycled crumb rubber (CR), recycled PVC particles, and reclaimed asphalt pavement (RAP) in different percentages on the performance of stone mastic asphalt (SMA) mixture against low-temperature cracking. PVC and CR additives were added to asphalt mix in two wet and dry methods. Thermal cracks are important and common failures of asphaltic pavements, and considerable financial budgets are allocated annually in different countries to deal with these damages. In this investigation, the fracture toughness of 16 various asphalt mixes at three distinct temperatures (temperatures of zero, −10, and −20° C) and under three diverse loading modes (including the mixed-mode I/ II, the pure mode II, and the pure mode I), were investigated by Semi-circular bending (SCB) fracture test. In addition to laboratory reports and mechanical studies, life cycle assessment (LCA) was utilized in this research to estimate and compare the influence of these asphalt mixes on the environment. The outcomes of mechanical tests and environmental analysis demonstrated that the usage of waste materials in this study has significantly enhanced the fracture strength of the SMA mix against low-temperature cracks and reduced its negative environmental effects. Therefore, the mixture containing RAP and 20% recycled PVC had the most satisfactory performance both in terms of environmental and fracture performance.

Stone Matrix Asphalt Performance with Glycerin Pitch as Asphalt Binder Extender

This research aims to utilize glycerin pitch waste as an alternative asphalt binder (extender) in Stone Mastic Asphalt (SMA) mixture. Glycerin pitch (GP) is a by-product from crude glycerol refining process from the palm oil oleochemical industry. The research method was carried out by testing the chemical and physical characteristics of GP by comparing it to pen 60/70, then testing based on asphalt binder rheology and asphalt concrete characteristics. ANOVA statistical test and Tukey-Kramer statistical grouping test were used to know the significant use of GP in SMA mixture. The variations of GP content tested to pen 60/70 were 0%, 15% and 25% by weight, then used as a binder for the SMA mixture which was tested under asphalt content (Pb) conditions based on Marshall characteristic, immersion index and drain down. The test results show that GP has the potential as an asphalt extender, with a maximum content of 22% by weight of asphalt binder or with a ratio of 1 GP: 4 pen 60/70. The characteristics of the SMA mixture using pen 60/70 and GP as asphalt binder extender, under conditions of Pb = 7% produce SMA mixture that meets the specification. Statistically, in stability characteristics of SMA, GP has a significant effect on SMA + 22% GP mixture. In the immersion index, the use of GP has a significant effect on all type of mixture, while in the draindown characteristics has significant effect on the SMA+0% GP mixture.

Advanced fatigue and rutting characterisation of Polish asphalt mixtures based on the VECD model and viscoplastic shift model

The advanced asphalt mixture performance-related specifications (AM-PRS) recently developed in USA can allow an optimisation of the design process of asphalt pavements thanks to the possibility to fully take into account the intrinsic material properties. In this study, four typical Polish mixtures, i.e. a Stone Mastic Asphalt (SMA) for wearing course, two mixtures for binder course with neat bitumen or Polymer modified Bitumen (PmB), and a mixture for asphalt base course with neat bitumen, were investigated by applying such advanced framework. The fatigue performance was studied through the simplified viscoelastic continuum damage (S-VECD) approach, whereas the rutting properties were assessed through the viscoplastic theory of the shift model. The findings were consistent with the composition of the studied mixtures, demonstrating the reliability and applicability of the AM-PRS even for typical Polish mixtures. Specifically, the high amount of soft PmB made the SMA mixture tough against fatigue cracking, but also more prone to rutting. The two binder mixtures exhibited good performance against both fatigue and rutting, and the polymer modification improved the toughness and increased the stiffness at high temperatures. The base mixture is expected to suffer fatigue cracking more than rutting, likely due to the low amount of bitumen and coarser aggregate gradation. These results can be used in the future for pavement performance predictions with FlexPAVETM software programme to ultimately optimise the design of Polish pavements.