Asphalt Binder Performance Grade Research Articles

Sustainability of Asphalt Mixtures Containing 50% RAP and Recycling Agents

The substitution of virgin asphalt binder with reclaimed asphalt pavement (RAP) has environmental and economic merits, however, cracking susceptibility arises due to the aged asphalt binder within RAP. The objectives of this study are to (1) enhance the cracking resistance of asphalt mixtures containing 50% RAP utilizing recycling agents (RAs) derived from six petroleum-based and bio-based materials, (2) conduct an environmental impact assessment (represented by global warming potential “GWP”) for high-RAP mixtures including RAs, and (3) estimate the cost effectiveness of including high-RAP content in asphalt mixtures. Based on the RAP asphalt binder performance grade (PG), base asphalt binder PG, and RAP content, the RA contents were determined to achieve a target asphalt binder of PG 76-22. A control mixture was benchmarked for comparison, specified for high-traffic volume roads, and contained PG 76-22 polymer-modified asphalt binder. The engineering performance of studied asphalt mixtures was evaluated using the Hamburg wheel-tracking (HWT), semi-circular bend, Illinois flexibility index, Ideal cracking tolerance, and thermal stress-restrained specimen tensile strength tests. It was found that petroleum-derived aromatic oil, soy-based oil, and tall oil fatty acid-based RAs demonstrated a successful restoration of aged RAP asphalt binder without compromising the permanent deformation resistance. The 50% RAP mixtures emitted less GWP by 41% and 42.9% using petroleum- and bio-oil RAs, respectively, and achieved a 31% cost reduction compared to the control mixtures.

Development of superpave asphalt binder specifications to meet climate conditions in the UAE

ABSTRACT Asphalt binder's performance is highly sensitive to temperature fluctuations and climatic conditions. The selection of an inappropriate asphalt binder leads to considerable damage and impacts roads' longevity. The current selection practice of asphalt binder in the United Arab Emirates (UAE) is mainly according to the penetration grading system, which does not consider local temperature conditions. The Superpave Performance Grade (PG) system considers extreme pavement temperatures to define appropriate asphalt binder PG. This study aimed at developing the Superpave asphalt binder PG map for the UAE. The Strategic Highway Research Program (SHRP) and Long-Term Pavement Performance Program (LTPP) Superpave models were used to calculate the pavement temperatures employing air temperature records collected from 20 weather stations across the UAE. The result of the Superpave PG map highlights three distinct asphalt binder grades at 98% reliability: PG 76-10, PG 70-10, and PG 64-10. The PG 76 -10 asphalt binder is the most prevalent PG, covering more than 85% of the UAE map. However, the current construction practice utilizes penetration grades 40/50 and 60/70, through both asphalt binders are equivalent to PG 64-xx. This necessitates the use of different modifier technologies to achieve the Superpave requirements of PG 76-10 and PG 70-10.

Global Warming and Its Effect on Binder Performance Grading in the USA: Highlighting Sustainability Challenges

The mounting impacts of climate change on infrastructure demand proactive adaptation strategies to ensure long-term resilience. This study investigates the effects of predicted future global warming on asphalt binder performance grade (PG) selection in the United States using a time series method. Leveraging Long-Term Pavement Performance (LTPP) data and Superpave protocol model, the research forecasts temperature changes for the period up to 2060 and calculates the corresponding PG values for different states. The results reveal significant temperature increases across the majority of states, necessitating adjustments in PG selection to accommodate changing climate conditions. The findings indicate significant increases in average 7-day maximum temperatures across the United States by 2060, with 38 out of 50 states likely to experience rising trends. Oregon, Utah, and Idaho are anticipated to face the largest temperature increases. Concurrently, the low air temperature has risen in 33 states, with notable increases in Maine, North Carolina, and Virginia. The widening gap predicted between required high and low PG poses challenges, as some necessary binders cannot be produced or substituted with other grades. The study highlights the challenge of meeting future PG requirements with available binders, emphasizing the need to consider energy consumption and CO2 emissions when using modifiers to achieve the desired PG properties.

Chemical, morphological, and rheological properties of biopolymer-modified asphalt containing waste polystyrene and pine resin

In recent years, much attention has been paid to improving the performance of asphalt binders, such as the use of polymers. Numerous investigations have shown that polymer modified asphalt exhibits a good resistance to rutting and reduced thermal cracking. However, incompatibility between asphalt and polymer occurs when a polymer is applied in high proportion. Using pine resin obtained from pine trees is expected as one approach to overcome this incompatibility. This study investigates the properties of biopolymer-modified asphalt consisting of conventional asphalt (60/70 penetration grade asphalt), waste polystyrene, and pine resin. Waste polystyrene at percentages of 4%, 6%, and 8% was blended with conventional asphalt, whereas 3% pine resin was applied to all mixtures. A series of tests was conducted, including penetration, softening point, flash point, ductility, specific gravity, mass loss, FTIR, SEM, EDX, and DSR. The results of the tests indicated that the pine resin predominantly contained aromatic oil, which is a good solvent to disperse waste polystyrene uniformly, thus increasing the compatibility of the mixture. The utilization of 6% and 8% waste polystyrene and pine resin improves the performance grade of the conventional asphalt binder, which is equal to PG 64 to PG 70.

Predicting flexural-creep stiffness in bending beam rheometer (BBR) experiments using advanced super learner machine learning techniques

BBR test is commonly used to assess the low-temperature performance grade (PG) of asphalt binders, with the flexural-creep stiffness being a critical parameter calculated through this test. However, it has notable limitations that demand attention. The significant amount of asphalt binder needed for test specimens increases costs and resource consumption. Additionally, the complex and time-consuming specimen preparation process hinders testing efficiency and introduces result variability, affecting the accuracy and reliability of PG determinations. In recent years, machine learning (ML) has emerged as a promising substitute for predicting various engineering values. In this study, the primary focus was on harnessing super learner (SL) techniques to predict the creep stiffness of asphalt binders. The SL approach combines multiple ML algorithms to enhance predictive accuracy and reduce individual model biases. Bagging, boosting, and stacking algorithms were employed in the construction of these prediction models. To conduct the investigation, data from 1350 samples sourced from the Long-Term Pavement Performance (LTPP) website were utilized to explore the influence of six crucial variables on the creep stiffness of asphalt binders. The proposed method demonstrated high accuracy, nearing 90% in the coefficient of determination. The Stacking model achieved a low Mean Absolute Percentage Error of 2.86% and robust Prediction Accuracy of 97.14% for randomly selected data points. Furthermore, the sensitivity analysis highlighted the significance of distinct input variables in influencing the creep stiffness of asphalt binders. Notably, the test temperature emerged as the most influential factor affecting creep stiffness, according to the conducted study

Incorporating Environmental Impact Analysis into Louisiana’s Balanced Asphalt Mixture Design

To meet the asphalt pavement industry’s net zero carbon emission goals, increasing reclaimed asphalt pavement (RAP) levels to greater than 25% is considered a critical tactic. However, many state departments of transportation are cautious in adopting high RAP content into their designs because of durability issues resulting from aged RAP binders. This paper assesses the effectiveness of using the Lewis acid catalyst, FeCl3, in improving the cracking resistance of high-RAP asphalt mixtures to meet Louisiana’s balanced mixture design (BMD) criteria, and lower embodied carbon of asphalt mixtures. Four asphalt mixtures were designed and tested against permanent deformation, intermediate- and low-temperature cracking, and durability. Mixture 1 is conventional, which contains performance grade (PG) 76-22 polymer-modified asphalt binder with no RAP. Mixture 2 is unmodified PG 67-22 and 30% RAP without catalyst. Mixtures 3 and 4 incorporated an unmodified asphalt binder PG 67-22, a catalyst, and 30% and 50% RAP, respectively. A life cycle assessment (LCA) analysis was conducted on asphalt mixtures that complied with Louisiana’s BMD specifications to quantify global warming potential improvements. Because the performance of both mixtures is expected to be similar, the scope of the LCA analysis was limited to only those life cycle stages that are expected to be different, modules A1–A3 (i.e., cradle-to-gate stages). Results showed that the use of FeCl3 can improve asphalt mixtures’ cracking resistance containing high RAP contents, whilst it did not have a negative impact on permanent deformation resistance. Further, the addition of FeCl3 to asphalt mixtures with 30% and 50% RAP levels showed a reduction in greenhouse gas emissions by 28% and 43.4%, respectively.

Influence of climate change on asphalt binder selection in China

ABSTRACT The impact of climate change on asphalt pavement infrastructure has become increasingly apparent. This paper investigated how climate change impacts the selection of asphalt binder for freeway pavement in China. The climate data predicted by the Global Climate Model were employed to select the appropriate performance grade for asphalt binder. The predicted air temperature converted pavement temperature, and performance grade distribution of the country was analysed. It is suggested that the performance grade of asphalt binder for freeways’ pavement should be determined based on ten years’ predicted climate data. This study concluded the following four major findings. Firstly, the selection of the appropriate asphalt binder performance grade needs to take into account the effects of future climate change. Secondly, the change in the standard deviation of temperature has a greater impact on the change in asphalt performance grade, as compared to the change in average air temperature. Thirdly, climate change affects the low-temperature performance grade more than the high-temperature performance grade in China. Finally, by 2050s, 15.2% of freeway asphalt pavement needs to upgrade high-temperature performance grade limit, and 17.3% of freeway asphalt pavement needs to upgrade to low-temperature performance grade limit.

Performance Zoning of Asphalt Pavement and Performance Grade (PG) of Asphalt Binder in Karamay: A Case Study of Xinjiang, China

Asphalt binder is a temperature-sensitive material with a performance that is greatly affected by changing climates. Improper selection of asphalt will cause a lot of damage and affect the durability of the road. The establishment of asphalt pavement performance zoning in Xinjiang, a vast area with great temperature differences, will provide a reference for the selection of asphalt suitability, the refinement of pavement design, and the sustainable development of road engineering. In this study, 11 years of temperature data in the Xinjiang region have been collected and analyzed, and 98% reliability of pavement design temperature has been used to draw a performance grading map of asphalt pavement in the Xinjiang region based on the ArcGIS platform. Finally, the Xinjiang region is divided into nine performance zones. At the same time, the performance grades (PG) of five kinds of asphalt binders in Karamay are explored. The result shows that there is little difference in continuous PG span between different matrix asphalt binders; the lower the penetration grade, the better the high-temperature performance, and the worse the low-temperature performance. After adding the SBS modifier, the continuous PG span can be about 20 °C higher than the matrix asphalt. The indoor test of asphalt mixture also shows that SBS-modified asphalt has better durability. All these provide the basis for a reasonable selection of asphalt binders in different areas of Xinjiang.

Time Dependent Release of Salts From Asphalt Pavement Containing Anti-Icer Additives

A laboratory investigation of anti-icing asphalt pavement (AIAP) containing salt storage additives (SSA) was carried out to explore the effect of pavement thickness, asphalt performance grade, and chloride salt composition on the salt release behavior through simulated precipitation wash cycle tests. The mass of salt release across repeated wash cycles over up to 2 years was quantified analytically and compared with typical NaCl brine anti-icing application rates. Consistent with previous studies, after an initial high release of salt, AIAP was found to settle into a roughly steady though gradually decreasing salt release over time and show a gradually increasing “regeneration” time required between precipitation events to recover to an effective anti-icing salt level at the surface. Given sufficient recovery time, the AIAP samples in these tests were able to release salt equivalent to 20 gal/lane mile of NaCl brine for an extended period. Pavement thickness between 0.625 and 1.25 in. and choice of asphalt binder performance grade between 58-28 and 64-22 were found to have little or no effect on the salt release behavior of AIAP, suggesting that adopters may exercise flexibility as needed within these ranges. The ratio of CaCl2 to NaCl in the SSA also had little or no effect on AIAP salt release behavior, indicating that formulators can focus on other potential performance functions for CaCl2.

Performance Evaluation of Extracted Asphalt Binders from Field Cores Containing Recycled Components: Load- and Non-Load-Associated Cracking Resistance

Modifying asphalt mixtures with recycled components is common practice due to their environmental and economic merits. However, due to the oxidized air-blown asphalt binders in recycled asphalt shingles (RAS) and aged binders in reclaimed asphalt pavement (RAP), adopting RAP and/or RAS as recycled components in asphalt mixtures influences the performance of the overall asphalt binder in these mixtures. The percentages of recycled components and performance grade (PG) of virgin asphalt binders (VABs) in the asphalt mixtures govern the performance of the overall asphalt binder. Therefore, the main idea of this study was to investigate the effect of the percentages of RAP/RAS and PGs of the VABs on the load- and non-load-associated cracking resistance of the extracted asphalt binders (EABs) from field cores. Rheological tests were performed on the EABs to assess the load-associated cracking (fatigue cracking) and non-load-associated cracking (low-temperature and block cracking) resistance. The VAB's PGs, mixtures' ages, and the percentages of RAP/RAS affected the EABs' cracking resistance. When compared to EABs from mixtures with lower amounts of RAP, employing RAS in the asphaltic mixtures improved EABs' resistance to fatigue and block cracking. However, using RAS deteriorated EABs' resistance to low-temperature cracking. Increasing the RAP's percentage in the asphaltic mixtures decreased the cracking resistance of the EABs. Strong relationships were established between EABs' load- and non-load-associated cracking resistance.

Effects of the addition of fatty acid from soybean oil sludge in recycled asphalt mixtures.

Recycling agents provide better additions of reclaimed asphalt pavement (RAP) in the production of new asphalt mixtures. Alternative and residual materials that have the potential as asphalt binder viscosity reducers have gained visibility in the field of paving due to the perspective of circular economy in recycled mixtures. Soybean oil sludge fatty acid is a material produced from soybean oil sludge, a waste generated in the soybean oil refining step. Thus, this paper investigated the physical, chemical, and rheological effects of the asphalt binder PG 64-XX modified by the fatty acid of soybean oil sludge in the contents of 6% and 7% by weight of the binder. The modified binder samples were submitted to penetration tests, softening point, rotational viscosity, performance grade (PG), before and after short-term aging (RTFO), and multiple stress creep and recovery (MSCR). A control asphalt mixture and recycled asphalt mixtures produced with 40% RAP and fatty acid-modified binders were subjected to tensile strength, induced moisture damage, resilient modulus, and fatigue life. A Student's t statistical test verified the significance of the data, as well as the estimation of production costs of these asphalt mixtures. The use of the fatty acid significantly reduced the stiffness and viscosity of the control asphalt binder, decreasing the mixing temperatures at 14°C and 17°C to 6% and 7%, respectively. Using higher fatty acid contents from soybean oil sludge significantly improved the performance of recycled mixtures in tensile strength, moisture damage, and fatigue life. The production cost of recycled asphalt mixtures was lower than that of the control mixture.

Long-term multi source analysis for asphalt binder PG selection using deep learning high air temperature modelling

As asphalt binder is a temperature-dependent viscoelastic material, the asphalt pavement performance is affected by the temperature during its service life. Traditionally, selecting the asphalt binder performance grade (PG) is based on long-term meteorological data analysis, but this study used MODIS and ASTER remotely-sensed (RS), reanalysis ERA5-Land, and in-situ meteorological datasets to select the PG. The multiple linear regression (MLR), genetic algorithm (GA), and deep-learning (DL) techniques were used to create models to estimate the maximum air and road pavement surface temperatures, considering the Superpave specifications. Model parameters involved the land surface temperature, vegetation index, elevation, ERA5-Land air temperature, soil moisture, wind speed, thermal radiation, evapotranspiration, latitude, and climate type. Comparative analyses revealed that the DL model yielded the most reliable PG results and the proposed RS-based method was more accurate than conventional approaches and could determine the PG accurately with 1 km resolution independent of distance to meteorological stations.

Rheological Properties of Asphalt Binder Modified With Reactive/Non-Reactive Polymer and Polyphosphoric Acid

This paper investigated the rheological performance of the combination of ethylene methyl acrylate and glycidyl methacrylate—EMA-GMA (reactive polymer)—and high-density polyethylene (HDPE) associated with polyphosphoric acid (PPA116%) in the modification of an asphalt binder (PG 64-XX). Tests such as performance grade (PG), multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and master curve vary the EMA-GMA and PPA116% contents to obtain an ideal composition to provide a high-performance asphalt binder and thus compare with an unmodified asphalt binder and a styrene-butadiene-styrene (SBS) modified asphalt binder. The results showed that the asphalt binder stiffness improved as the EMA-GMA and PPA116% content increased. The PG temperature increased with the addition of PPA116% content in the asphalt binder samples, being most significant with the use of 1.8% of EMA-GMA. The addition of the combined polymers decreased the susceptibility to rut and improved the elastic recovery of the asphalt binder PG 64-XX, but only the samples with 1.8% EMA-GMA showed higher elastic recovery than the SBS-modified binder. PPA116% provided benefits in damage resistance at all strain levels; however, more was observed in samples subject to minor strains. The incorporation of 1.8% EMA-GMA, 0.3% HDPE, and 0.5% PPA116% was the one that presented the most improvements, without presenting gelation, in the performance of the asphalt binder in relation to stiffness and elasticity with increasing temperature. Thus, the use of these polymers in this composition can be a good alternative to regions with high temperatures, such as the northeast region of Brazil.

Use of spiral cracking patterns in fracture characterization of asphalt materials

A new approach for fracture characterization of asphalt materials through use of spiral cracking patterns is presented. Five different asphalt materials each at three different oxidative-aging levels, were utilized in this work. An efficient image processing framework using Convolutional Neural Networks (CNN) was implemented to analyze spiral cracking images. Results showed that spiral tightness parameter was sensitive to fracture energy, performance grade (PG), and oxidative aging level of asphalt binders. Machine learning approaches such as XGBoost and Elastic-Net regularized regression were employed to develop prediction models to estimate fracture in asphalt materials.

Improving the Performance Grade and Traffic Loading of Egyptian Asphalt Binders by Recycled Polyethylene Modification

Recent SUPERPAVE technology allows assessment and performance grading (PG) of modified asphalts according to AASHTO T 350–14 and ASTM D7405-15 standards. These testing protocols use modified - multiple stress creep recovery (MSCR) test, to yield the high temperature PG and the traffic level of the asphalt binder. Latest AASHTO T 350–14 test protocol is used to assess two major Egyptian bitumen products, Alex and Suez (pen 60/70) before and after polymer modification. These standard products have different fractional composition since they are obtained from different local origins. Low density polyethylene modification (LDPE) of such products leads to a major enhancement in their PGs and decreases their high temperature rutting potential. A characteristic comparison between virgin a and LDPE modified bitumen samples is provided to achieve the desired PG and traffic level for high reliability projects deployed in Egyptian hot climate regions. it was found that a 2% wt recycled LDPE modification, enhances the high temperature performance grade and the traffic grade from PG 58S-XX to PG 64S-XX for the bitumen produced by Alexandria Oil Company, and from PG 58S-XX to PG 70S-XX for the bitumen produced by Suez Oil Company.

Investigating the potential of using dry battery waste powders (DBWPs) as a modifier for asphalt binders

This study aims at investigating the potential of using dry battery waste powders (DBWPs) as modifiers in asphalt binder. A 60/70 penetration grade asphalt binder was used in this study. DBWPs, which were extracted from spent batteries, were mixed with the asphalt binder at seven different percentages [0% (control sample), 2%, 4%, 6%, 8%, 10%, 15%, and 20% by weight of asphalt binder]. The mixing process was performed at 175 °C for 30 min using a high-speed mechanical mixer. To study the effect of DBWPs on asphalt binder properties, both traditional and Superpave binder tests were carried out. Consistency tests included penetration, softening point, and ductility, while Superpave tests included Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR). Flash and fire point tests were also conducted. The test results indicated that the addition of DBWP to the asphalt binder decreased ductility and penetration values and increased the softening and the flash and fire points of the asphalt binder. High-temperature rutting performance of asphalt binder, as presented by DSR rutting parameter (G*/sinδ), was improved by adding DBWP. The high-temperature performance grade of asphalt binder was raised by one grade by adding DBWP up to 10%, two grades at 15%, and three grades at 20%. On the other hand, fatigue and low-temperature performance of asphalt binder were adversely affected by adding DBWP. The Superpave fatigue parameter (G*.sinδ) was negatively increased by increasing the content of DBWP but remained less than the Superpave limit (≤ 5000 kPa). The low-temperature asphalt binder grade was decreased from − 22 °C (for control asphalt binder) to − 16 °C at 15% DBWP and then to − 10 °C at 20% DBWP. Therefore, it is recommended to use DBWP modifier in high-temperature regions to resist rutting distresses.

Prediction of modified asphalt concrete rutting depth using statistical model

Permanent deformation is considered one of the main distresses in flexible pavement. It can be defined as the accumulation of unrecoverable strains under the wheel paths as a result of applied load. The main objectives of this research is firstly to study the effect of using (SBS) (Styrene Butadiene Styrene) as elastomer polymers and (PVC) (Polyvinyl Chloride) as plastomer polymers on performance grade of asphalt binder and secondly to predict the deformations that produced in asphalt pavement related to the structure of the pavement, climate condition and load traffic. In this study, 2% and 4% of PVC were added for both neat asphalt and asphalt modified with 2% SBS. Dynamic Shear Rheometer (DSR) device was used to achieve the performance grade (PG) of modified asphalt binder whereas roller compactor and wheel track devices were used to assess rut depth. The model has been developed from the data which gathered by experimental tests for permanent deformations with independent variables such as: number of cycles, viscosity according to the type of additive, aggregates gradation and degree of temperature by using SPSS software. The results demonstrated that the PG of the neat asphalt binder increased by three and four degrees when 2% and 4% of PVC were added to asphalt modified with 2% of SBS respectively, while it increased by one and two degrees when 2% and 4% of PVC were added to the neat asphalt respectively but it increased by two degrees when added 2% of SBS to the neat asphalt binder. From the results which were obtained from the analysis of sensitivity, it is appeared that the temperature significantly influences on rut depth of the pavement. Also, the results showed that the increasing of coarse aggregate percentage in a mix will cause an increasing in the depth of rut. Furthermore, it is found that increasing percentages of polymers types led to increase asphalt viscosity and as a results the rut depth of asphaltic mixture will be reduced.

Effect of Styrene-Butadiene-Styrene on the Properties and Grading of Local Asphalt Binder in the UAE

Flexible pavements in the UAE are subjected to heavy traffic loading repetitions and severe weather conditions which are the main causes of local pavement deteriorate. Fatigue cracking and rutting are most common deterioration types. One effective solution to mitigate both pavement distresses is to use asphalt modifier technologies to improve the properties of asphalt binders used locally in the UAE. The main goal of this study is investigating the effects of Styrene-Butadiene-Styrene (SBS) on the rheological properties of local asphalt binder as well as its grade based on both penetration and Superpave grading systems. Three different SBS contents of 2.5%, 4.5%, and 6.5% by weight of asphalt binder were utilized. It was found that increasing SBS content increased the asphalt binder softening point and rotational viscosity and decreased the penetration value. SBS-modified asphalt binders were less susceptible to temperature changes. Superpave performance results showed that SBS-modified asphalt binders exhibited higher rutting parameter G*/Sin δ values as the SBS content increased for both unaged and short-term-aged conditions. Adding 2.5% SBS increased the asphalt penetration grade from 60/70 to 40/50 and the performance grade (PG) from 64 to 70. For the 4.5% and 6.5% SBS cases, the asphalt binder PG increased to 76 and 88 respectively. SBS-modified asphalt binders were found to possess significantly higher mixing and compaction temperature ranges compared to the control asphalt binder.

The potential use of recycled polyethylene terephthalate (RPET) plastic waste in asphalt binder

The current study aims to examine the potential use of recycled polyethylene terephthalate (RPET) plastic waste as a modifier for asphalt binder. Plastic bottles were collected, shredded, cleaned, melted, ground, then sieved. An asphalt binder with a penetration grade of 60/70 was used. The RPET plastic waste was blended with 60/70 penetration grade asphalt binder at five percentages (0, 5, 10, 15, and 20 %, by weight of asphalt binder) using a high shear mixer. To study the physical and mechanical properties of RPET-modified asphalt binders, both traditional and Super pave tests were conducted. The test results showed that by incorporating RPET into asphalt binder, the ductility and penetration values decreased, whereas the softening point and viscosity of asphalt binder increased. Furthermore, the rutting performance of RPET-modified asphalt binder, as presented by the rutting parameter (G*/sinδ), was enhanced by increasing the amount of RPET plastic waste at all testing temperatures. The high-temperature performance grade of asphalt binder was raised by one grade (from 64°C to 70°C) by adding 15% and 20% of RPET plastic waste. On the other hand, the low-temperature performance of asphalt binder, as presented by creep stiffness and m-value, was negatively affected by adding RPET. The low-temperature performance grade of asphalt binder was dropped by one grade (from −22°C to −16°C) by adding RPET plastic waste at percentages of 15 % and 20 %. Moreover, the fatigue cracking performance of asphalt binder, as presented by the fatigue parameter (G*.sinδ), was slightly reduced by adding RPET to the asphalt binder but remained lower than the acceptable Super pave limit (≤ 5000 kPa).

Investigating the Effect of Using Waste Ultra-high-molecular-weight Polyethylene on the Fatigue Life of Asphalt Mixture

One of the effective parameters in the occurrence of fatigue cracking distress is the asphalt binder properties used, which must be controlled by appropriate asphalt binder or additives. In this study, the effect of using Ultra-High-Molecular-Weight Polyethylene (UHMWPE) was investigated on the fatigue cracking potential of asphalt mixtures. Two types of aggregates, asphalt binder performance grade (PG) 64-16, and UHMWPE additive in two percent of the asphalt binder were used in this study, which were tested at two temperatures and five different stress levels. Marshall mix design and indirect tensile fatigue test (ITFT) were used to determine the optimum content of the asphalt binder and the fatigue life of asphalt mixtures, respectively. The results of this study indicated that the application of polymer additives increased the fatigue life of the asphalt mixtures. The fatigue life of specimens made with granite aggregates was longer than those made with limestone aggregates, and the increased life due to the use of UHMWPE was longer in samples made with granite aggregates. As expected, increasing in temperature and stress levels reduced the fatigue life of the asphalt mixtures. This decrease was much lower in samples made of asphalt binder modified with polymeric materials than in control samples.