High Temperature Performance Of Asphalt Binder Research Articles

Influence of Biomass-Modified Asphalt Binder on Rutting Resistance

Biomasses are environmentally friendly additives that lower pollution in pavement engineering because of their biodegradability. On the other hand, to build a safe, long-lasting pavement, rutting prevention is crucial. This study provides a comprehensive review of the efficacy of biomass as recyclable materials in reducing rutting and enhancing characteristics of asphalt mixtures. According to findings, the hydrocarbon polymer properties of lignin and biomass ash improve asphalt binder consistency, hardness, and function at high temperatures. The results showed that biochar, due to its solid shape, enhances the stiffness and viscosity of the mixtures. The high-temperature performance of asphalt binder is improved by bioshell waste, which increases rutting parameters. Thus, biomass like ash, lignin, and biochar can increase asphalt binder rheology and rutting resistance due to chemical forces such as Van der Waals and hydrogen ions. The macroscopic and microscopic investigation also shows higher interaction and better adhesion in bioasphalt. However, asphalt binders containing bio-oil exhibited no unique behaviors due to their lubricant impact. Based on the estimation of the life cycle assessment (LCA), it was determined that biomass utilization has the potential to decrease the cost and CO2 emissions of pavement engineering by as much as 10% and more than three times, respectively. An examination of recyclability revealed that biomass utilization can decrease the requirement for additional stabilizers by as much as 20%.

Nonlinear viscoelastoplastic kinetics for high-temperature performance of modified asphalt binders

Modified additives are widely used to improve the high-temperature performance of asphalt binders. However, the high-temperature performance of modified asphalt binders cannot be well evaluated by the existing methods. To address this issue, this study aims to develop a new nonlinear viscoelastoplastic kinetics method to evaluate the high-temperature performance of modified asphalt binders. Styrene-butadiene-styrene (SBS), rubber modified asphalt binders and their aged materials are employed. First, the non-recoverable creep compliance from the standard and modified Multiple Stress Creep and Recovery (MSCR) tests are used to evaluate the high-temperature performance of asphalt binders. Then, the viscoplastic strain and activation energy from creep-recovery tests are adopted to evaluate the high-temperature performance of asphalt binders based on nonlinear viscoelastoplastic kinetics method. Results show that the high-temperature performance results from the standard and modified MSCR tests are inconsistent. The viscoplastic strain of unaged SBS modified asphalt binders shows different trends compared with other asphalt binders. It rapidly increases at the initial loading stage, then follows by a reinforcement period, and finally maintains a steady growth rate, while the reinforcement period will disappear after aging. The viscoplastic activation energy from the nonlinear viscoelastoplastic kinetics method can characterize the stable high-temperature performance of asphalt binders, avoiding controversy caused by the number of cycles in MSCR tests.

Sprayed-Polyurea-Modified Asphalt: Optimal Preparation Parameters, Rheological Properties and Thermal Properties

For promoting modifying application of sprayed polyurea (SPUA) in asphalt pavement materials, the effects of sprayed polyurea materials on high-temperature and fatigue performance of asphalt binders were investigated from different aspects. First, the optimal preparation parameters of sprayed-polyurea-modified asphalt binders (SPMAs) were determined by designing an orthogonal test. Then, the high-temperature and fatigue properties of sprayed-polyurea-modified asphalt binders with different contents were characterized by rheological testing methods, including Brookfield rotary viscosity (RV) test, performance grading (PG) test, multiple stress creep recover (MSCR) test, linear amplitude sweep (LAS) test and time sweeping (TS) test. Finally, the thermal properties of the asphalt binders were analyzed by differential scanning calorimetry (DSC) test. The results showed that the optimum preparation parameters were determined by the extreme difference analysis method and analysis of variance (ANOVA) method, and the shearing time was 40 min, the shearing rate was 6000 rpm and the shearing temperature was 150 °C. Sprayed polyurea positively affected high-temperature performance of asphalt binders and could improve fatigue resistance of asphalt binders. Moreover, the Brookfield rotary viscosity test, multiple stress creep recover test and linear amplitude sweep test had high sensitivity to the performance of sprayed-polyurea-modified asphalt binder, which could help to distinguish the effect of sprayed polyurea dosing on performance of asphalt binders accurately. The differential scanning calorimetry test showed that sprayed polyurea was beneficial to high-temperature stability of asphalt binders, which explains the reason why sprayed-polyurea-modified asphalt binders have excellent high-temperature performance from a microscopic perspective.

Rutting-resistance investigation of amorphous carbon powder modified binder and asphalt mixture containing siliceous aggregates

ABSTRACT Amorphous carbon powder (ACP), an industrial waste material, is a potential asphalt binder modifier. In this study, the effect of ACP on the rutting performance of asphalt binders and mixtures was investigated. For this purpose, the frequency sweep, and multiple stress creep recovery tests of asphalt binders and resilient modulus, dynamic creep, and wheel tracking tests of asphalt mixtures were conducted on asphalt binders and mixtures containing 3, 5, and 10% of ACP by weight of total asphalt binder. The results showed that using 10% ACP caused a substantial improvement in the rutting parameter of asphalt binders, and the non-recoverable creep compliance values at both 0.1 and 3.2 kPa stress levels decrease by about 80% when modified with 10% ACP. The asphalt mixture results indicated that the indirect tensile strength, wheel tracking, and resilient modulus at 25°C enhanced by about 25%, 43%, and 40%, respectively when 10% ACP modified asphalt binder was used. Therefore, in addition to being a positive action in environmental protection, modifying asphalt binders with 10% ACP can improve the high-temperature performance of asphalt binders and mixtures.

Coupled Effects of Gilsonite and Sasobit on Binder Properties: Rheological and Chemical Analysis

Experiences of highway agencies show that the costs of repairing rutting distresses are high. The common solution to overcome this issue is using a modified asphalt binder. The modifier enhances the asphalt binder’s rheological and physical properties but increases the production temperatures of asphalt pavement. Nevertheless, warm mix asphalt (WMA) production at temperatures lower than hot mix asphalt (HMA) could lead to lower aging of asphalt binders. In this study, the physical and rheological properties of modified asphalt binders with different contents of Gilsonite and their combination with Sasobit as a WMA agent were investigated. Accordingly, 5%, 9%, and 13% Gilsonite, as well as 3% Sasobit in combination with Gilsonite, were used to modify asphalt binders. Dynamic shear rheometer (DSR), rotational viscosity (RV), surface free energy (SFE), Fourier-transform infrared spectroscopy (FTIR), and some conventional tests (i.e., penetration grade, softening point, and storage stability) were conducted to evaluate the properties of the binders. The results of chemical analysis tests (i.e., SFE and FTIR) indicated that using Gilsonite and Sasobit as composite modifiers could further improve the thermomechanical properties. The DSR test results also showed that the Gilsonite and its combination with Sasobit improve the high-temperature performance of asphalt binders and, consequently, increase the rutting resistance. However, Gilsonite could raise the asphalt binder elasticity and showed better results when Sasobit was incorporated. In general, Gilsonite increased the asphalt binder stiffness, and consequently, it could reduce the workability and compactability of mixtures. Therefore, the use of Sasobit as a complement for Gilsonite reduces the viscosity of the asphalt binder and enhances the mixture workability. This could pave the way to use Gilsonite in WMA, resulting in more durable and sustainable asphalt mixtures.

Comparison and Evaluation of Different Test Methods and Models for Determining Zero Shear Viscosity of Asphalt Binder

Zero shear viscosity (ZSV) has been proven to be a reasonable indicator for characterizing the high-temperature performance of asphalt binders. Various test methods and models have been used in the literature to determine the ZSV, while no consistent result can be obtained. In addition, the differences and similarities among these methods are not yet clear, which can often bring difficulties and confusion to researchers when trying to implement the ZSV methods. This paper aims to evaluate the applicability of different test methods and rheological models in determining the ZSVs of asphalts. The shear rate sweep test, frequency sweep test, and creep test were performed on 60/80 and 80/100 pen grade base asphalts and styrene-butadiene-styrene (SBS) modified asphalt, and ZSVs were determined using Carreau’s model, Carreau-Yasuda model, Cross/Sybilski’s model, Cross/Williamson’s model, Burger’s model, the threshold method, and the ratio method. The test results showed that the shear rate sweep test and the creep test have lower variability and better applicability than the frequency sweep test, and the four rheological models and the threshold method used in the shear rate sweep test could determine the ZSV well. In the frequency sweep test, the Cross/Sybilski’s model failed to determine the ZSVs of all asphalts, and the ZSV of SBS asphalt could only be calculated by the ratio method. Under different test methods and models, the ZSVs of each base asphalt were similar, while that of SBS asphalt were significantly different. Considering the time consumption and applicability of the test, the shear rate sweep test seems to be the most promising test method for determining ZSVs.

Environment Effect on the Rutting Resistance of Nano-SiO2-Modified Asphalt Concrete: Temperature and Water

Nanoparticles have been widely adopted to improve the high-temperature performance of asphalt binder. However, the influence of moisture on high-temperature performance is not clear. Hence, the water absorption performance of the nano-SiO2-modified asphalt concrete is investigated. Based on this, to further analyze the pavement performance of the nano-SiO2-modified asphalt concrete, the coupled effects of high-temperature, moisture content, and nanoparticles content on the rutting resistance of the nano-SiO2-modified asphalt concrete are tested and revealed in this study. Results show that temperature has the most significant influence on the water absorption performance of the nano-SiO2-modified asphalt concrete. The rutting resistance of the nano-SiO2-modified asphalt concrete decreases as temperature and moisture content increase, especially for the temperature. The dynamic stability at the same temperature condition decreases approximately linearly as moisture content increases. The effect of the nano-SiO2 content is the most nonobvious.

Rheological Properties of Graphene/Polyethylene Composite Modified Asphalt Binder.

Aiming to improve the comprehensive road performance of asphalt binders, especially the high-temperature performance, a novel asphalt binder was prepared by compounding high-quality and low-cost polyethylene (PE) with graphene (GNPs) using a high-speed shearing machine. The rheological properties and interaction mechanism of PE/GNPs composite modified asphalt were investigated using temperature sweep (TeS), multiple stress creep recovery (MSCR), linear amplitude sweep (LAS) and Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM). The experimental results demonstrated that GNPs and PE can synergistically improve the high-temperature performance of asphalt binders and enhance the rutting resistance of pavements; the pre-blended PE/GNPs masterbatch has good medium-temperature fatigue and low-temperature cracking resistance. Meanwhile, PE/GNPs dispersed uniformly in the asphalt matrix, and the microstructure and dispersion of premixed PE/GNPs masterbatch facilitated the asphalt modification. No new absorption peaks appeared in the FT-IR spectra of the composite modified asphalt, indicating that asphalt binders were physically modified with GNPs and PE. These findings may cast light on the feasibility of polyethylene/graphene composite for asphalt modification.

Analysis of MSCR test results for asphalt binders with improved accuracy

The multiple stress creep recovery (MSCR) test has been regarded by many as the best available test method to evaluate the high-temperature performance of asphalt binders. However, recent studies have shown that the 9-s recovery time may not allow a full recovery of viscoelastic strain for some modified asphalt binders. In that case, some potential viscoelastic recovery is mistakenly reported as unrecovered strain, leading to an underestimation of the asphalt binder rutting resistance. In order to address the issue of incomplete recovery, this paper developed a mechanistic modeling approach to analyze the MSCR test results of six types of asphalt binders. Before using the mechanistic modeling approach, the steady-state strain response at each stress level was firstly determined for all asphalt binders. It was found that the three neat asphalt binders reached a steady-state condition from the beginning of the last 10 cycles, whereas the SBS-modified asphalt binders reached a relatively steady state in the last 5 cycles. Afterwards, a mechanistic modeling approach was employed to analyze the shear strain data in the last 5 cycles at each stress level based on the Boltzmann superposition principle and the Schapery’s nonlinear viscoelastic theory. The viscoplastic strain at the end of the recovery portion and the viscoelastic strain at the end of the creep portion were utilized to calculate the non-recoverable creep compliance and percent recovery. It was demonstrated that the approach adopted in this study was capable of analyzing the MSCR test results of asphalt binders with improved accuracy.

High-Temperature Performance of Asphalt Mixtures: Preliminary Analysis for the Standard Technical Index Based on Gray Relational Analysis Method

Aiming to evaluate the high-temperature performance of asphalt binders and asphalt mixtures and to investigate the reliability of the standard technical indexes to evaluate the performance of the asphalt, six typically used asphalt types were employed in this study. The standard high-temperature rheological test, the multiple stress creep recovery (MSCR) test, and the zero-shear viscosity (ZSV) test were employed to characterize the high-temperature performance and non-Newtonian fluid properties of the asphalt. Meanwhile, the high-temperature performance of the asphalt mixture was evaluated through the rutting tests based on the mixture design of AC-13. In general, the modified asphalt performed better than the unmodified asphalt according to the high-temperature rheological properties tests. The ranking of the six kinds of asphalt was confirmed to be different in various laboratory tests. The test results of the asphalt binders showed that the Tafpack Super- (TPS-) modified asphalt performed best in the MSCR and ZSV tests, while the low-grade asphalt PEN20 had the best technical indexes in the dynamic shear rheometer (DSR) test. Besides, the relation between the asphalt and the asphalt mixture was analyzed by gray relational analysis (GRA) method. The present rutting indicator G ∗ / sin δ and G ∗ / 1 − sin δ ⋅ tan δ − 1 for evaluating the asphalt mixtures’ high-temperature performance might no longer be suitable. The Cross/Williamson model was the most suitable for calculating and fitting the ZSV, which could be used as the key indicator of the high-temperature performance evaluation of the asphalt. This work lays a foundation for the further study of the high-temperature performance evaluation of asphalt binders.

Exploring the feasibility of using reclaimed paper-based asphalt felt waste as a modifier in asphalt-binders

Paper-based asphalt felt, which is typically used as a waterproofing material, is one of the most problematic solid wastes in terms of disposal and environmental contamination. The laboratory work presented in this paper aims to propose a strategy for utilizing the reclaimed paper-based asphalt felt (RPAF) waste in hot-mix asphalt (HMA) pavements as a means to mitigate the RPAF disposal problem. A series of laboratory tests, including viscosity, modulus, rutting, and cracking, were conducted to investigate the effects of RPAF additives on the engineering performance of asphalt-binder and HMA mixes. The corresponding test results showed that the addition of RPAF improves the viscosity and high-temperature performance of asphalt-binders. However, RPAF modified asphalt-binder exhibited inferior storage stability than the virgin asphalt-binder due to the difference in density between the asphalt-binder and RPAF components. Additionally, the effect of RPAF on the rheological characteristics of the asphalt-binder exhibited high sensitivity to temperature. The differences in complex modulus and phase angle of the asphalt-binder with RPAF additives were generally more significant at elevated temperatures. Similarly, RPAF modified HMA mixes outperformed the control HMA mix in terms of resistance to moisture damage, rutting, and cracking, respectively. Overall, the laboratory test results indicated that it is feasible to utilize RPAF waste as an asphalt-binder modifier to enhance the engineering properties/performance of the asphalt-binder and HMA mix whilst simultaneously addressing the environmental issues of RPAF waste disposal.

Evaluating the Effect of Rice-Husk Ash and Crumb-Rubber Powder on the High-Temperature Performance of Asphalt Binder

AbstractThe objective of this paper was to evaluate the effect of using rice husk ash (RHA), crumb rubber powder (CRP), and combination of RHA and CRP (RHA/CRP) on the high-temperature performance ...

Investigation on high-temperature performance of waste-based high-viscosity asphalt binders (WHABs) by repeated creep recovery (RCR) test

This study reviewed and compared the test methods for the high-temperature performance of asphalt binder, and selected repeated creep recovery (RCR) test to evaluate the high-temperature performance of three waste-based high-viscosity asphalt binders (WHABs, including D-I, D-II, and F) and a control sample (Tafpack-Super modified asphalt, TMA). Meanwhile, shear stress, test temperature, and aging degree of binders, which could influence high-temperature behavior of binders, were also investigated, and related evaluation indexes including recovery compliance (R), non-recoverable creep compliance (Jnr), and viscous stiffness modulus (Gv) were compared. Results show that WHABs has much better high-temperature performance than TMA; shear stress has the most prominent effect on binders’ high-temperature performance, followed by aging degree, and lastly the selected test temperature in γ–time curve results; R, Jnr, and Gv values results indicate aging degree has a significant effect on binders, and improving binders’ aging performance can greatly improve the high-temperature performance.

Performance of Warm-Mixed Flame Retardant Modified Asphalt Binder

In order to analyze the effect of flame retardant and warm mix asphalt (WMA) additives-Sasobit on the flame-retardant performance and pavement performance of asphalt binder, the limiting oxygen index test, conventional performance test, and Superpave evaluation index tests were performed on asphalt binders in the study. The test results show that flame retardant can effectively improve the flame resistance of asphalt binder, while Sasobit has a certain combustion-supporting effect. Therefore, when warm-mixed flame-retardant technology is applied, the concentration of Sasobit should be controlled appropriately. These two modifiers can significantly enhance the high-temperature performance of asphalt binder, but both of them have a slight negative influence on the low-temperature cracking resistance. Sasobit can substantially reduce the high-temperature viscosity of asphalt binder, which helps to improve the construction workability of asphalt binder, while the flame retardant adversely affects the viscosity reduction effect of Sasobit to a certain extent, but the overall impact is not large.

Effects of ethylene vinyl acetate and nanoclay additions on high-temperature performance of asphalt binders

This study investigates the effects of adding ethylene vinyl acetate (EVA) copolymer and nanoclay (NC) on the high-temperature performance of asphalt binders. Three different types of modified binders were prepared using melt blending, NC-, EVA-, and polymer-modified nanoclay at concentrations of 1, 3, 5, and 7 wt%. Their physical and rheological properties were evaluated by conventional tests (penetration and softening point), viscosity measurements, and a dynamic shear rheometer. The results show that EVA and NC significantly improve the binder properties. Specifically, the rutting parameter increased after binder modification indicating its superior performance at high temperatures.

Storage stability and high-temperature performance of asphalt binder modified with recycled plastic

Huge amounts of generated non-degradable plastic wastes constitute a major global environmental nuisance. The combined annual municipal solid waste (MSW) generation of Saudi Arabian Kingdom (KSA) exceeds 14,000,000 tonnes, with an average per capita of 1.4 kg/day. Plastic wastes constitute up to 10% of these MSW. The local asphalt can only perform satisfactorily without polymer modification in an environment with a maximum pavement temperature below 64°C. But the 7-day maximum pavement temperature ranges between 64°C and 76°C within the Kingdom. Dynamic storage stability, high-temperature performance, non-recoverable creep compliance (Jnr), and strain recovering tendency of recycled high- and low-density polyethylene (RHDPE and RLDPE), and recycled polypropylene-(RPP) modified asphalt binders in combination with styrene–butadiene–styrene (SBS) and polybilt (PB) were presented in this study. Improved high-temperature performance was observed. Even though the recycled plastic waste-modified binders lack sufficient strain recovering ability, RLDPE and RHDPE could be utilised along with an elastomeric SBS to achieve a higher recovery and strain resistance, than that which could be achieved if the same amount of SBS alone is used. RPP content above 2% will lead to an unstable modified asphalt binder. The RHDPE content below 4% and the RLDPE content below 6% whether containing either SBS or PB have shown good storage stability trait under mild agitation, in terms of both time degradation and separation.

Effect of introduction of furfural on asphalt binder ageing characteristics

Asphalt oxidative ageing and excessive hardening are known causes of premature pavement cracking. Asphalt ageing occurs mainly due to the oxidation of certain functional groups in asphalt as well as the loss of the maltene phase disturbing colloidal stability and increasing micellisation concentration. This in turn can cause large non-soluble asphaltene aggregates which are typically suspended in the maltene solution and are stabilised by resin molecules to flocculate. Flocculation can cause the asphalt to become stiffer and more brittle. It should be noted that excessive hardening and brittleness of asphalt caused by oxidation during pavement production and service life increase the susceptibility of asphalt pavements to cracking. Therefore, reducing the extent of asphalt oxidation could increase pavement service life. Therefore, it is imperative to reduce/delay asphalt oxidation in asphalt binder. There have been several studies on delaying asphalt oxidation by introducing modifiers and anti-ageing additives. Furfural, an organic compound derived from a variety of agricultural by-products, has been shown to be a promising modifier for petroleum asphalt binders used in asphalt pavement. Accordingly, this paper investigates the effect of introducing furfural as an antioxidant for asphalt by evaluating the extent of oxidation ageing in asphalt specimens modified by 1%, 2% and 5% furfural. To do so, furfural was introduced to asphalt and the level of change in physiochemical and rheological properties of asphalt after specimens were exposed to short- and long-term ageing was examined. Accordingly, performance characteristics of the base asphalt were compared with those of furfural-modified asphalts using a rotational viscometer, Fourier transform infrared spectroscopy and a dynamic shear rheometer to evaluate the rheological properties of asphalt modified with furfural at different percentages. The study results showed that the addition of furfural helped reduce the extent of oxidative ageing while enhancing high-temperature performance of asphalt binder. Specifically, it was found that the 2% furfural modification had the lowest ageing index after ageing, indicating an improvement in binder oxidative ageing.

Investigation of the potential application of biodiesel by-product as asphalt modifier

The potential application of biodiesel by-product as an asphalt modifier was investigated in terms of chemical composition and performance grades tests. Modified asphalt binders were prepared by adding four contents of biodiesel by-product into control binder. First, Fourier transform infrared spectroscopy (FT-IR) test was conducted to investigate the chemical composition and modification mechanism of experimental materials. Then, rotational viscometer test for original asphalt, dynamic shear rheometer test for original, rolling thin film oven-aged and pressure ageing vessel (PAV)-aged asphalt, bending beam rheometer test for PAV-aged asphalt were carried out to investigate the effect of biodiesel by-product on performance grades of control asphalt binder. Finally, storage stability test was conducted to analyse the segregation tendency of by-product-modified asphalt binders. The FT-IR test results indicated that no chemical reaction occurred between control asphalt and biodiesel by-product. Meanwhile, the addition of biodiesel by-product reduced the rotational viscosity of the asphalt binder, hence lowered the optimum mixing and compaction temperatures of asphalt concrete. Moreover, the addition of biodiesel by-product decreased the high-temperature performance of asphalt binder, while improved the low-temperature performance and fatigue resistance performance. In addition, a good storage stability of by-product-modified asphalt binders was noticed. Finally, considering the performance variations of by-product-modified asphalt and environmental requirements, the content of by-product recommended to be used as PG64-16 asphalt binder's modifier in cold region was 4%.

Analysis of different indices for high- and low-temperature properties of asphalt binder

The high- and low-temperature performance of asphalt binders have an important effect on the rutting and cracking resistance of asphalt pavements, thus these are two of the most important performance of asphalt binders. Nowadays, there are many indices to evaluate the high- or low-temperature performance of asphalt binders respectively. But there is still no unified option about which index is better.As a kind of typical viscoelastic materials, both of the high-temperature performance and the low-temperature performance of asphalt binders are related to viscoelastic characteristics of asphalt binders, but they are opposite to each other. That is, a binder needs to have more elastic part for high-temperature performance but more viscous part for low-temperature performance. So the ratio of viscous part to elastic part is important to high- and low-temperature performance of asphalt binders. Based on that thought, a new index based on viscoelastic characteristics, referred to as RJ, is developed in this study. Different high- and low-temperature evaluation indices including RJ were analyzed by comparing the performance ranking evaluated by them with the ranking of the corresponding mixtures. The correlation between performance of binders evaluated by different indices and the performance of the corresponding mixtures were also analyzed. Based on the results, zero shear-rate viscosity and non-recoverable stiffness is found to be suitable for evaluating the high-temperature performance of asphalt binders, stiffness at 60s from BBR is found to be suitable for evaluating the low-temperature performance of asphalt binders. The established evaluation index, RJ, is found to be suitable for evaluating both performances of asphalt binders.

Influence of Rubber Powder Content on High-Temperature Performance of TOR Rubber Asphalt

Six kinds of TOR rubber asphalts with 5%-30% rubber powder contents of were selected to carry out conventional high-temperature tests and dynamic shear rheological tests to obtain some parameters reflecting the high-temperature performance of asphalt binders, such as softening point, dynamic viscosity at 60°C, rutting factor (G*/sinδ) at 60°C and critical temperature of rutting factor (TG*/sinδ). The results show that the changing tendency of two rheological parameters of TOR rubber asphalts, G*/sinδ at 60°C and TG*/sinδ, is ascend in first and descend at last with the increase of rubber powder content proportion. The high-temperature performance of TOR rubber asphalt with the rubber powder content about 20% is the best. Softening point and dynamic viscosity at 60°C, as two conventional high-temperature parameters of asphalt binders, can describe the high-temperature performance of TOR rubber asphalt with the rubber powder content below 20%, but cannot evaluate accurately the high-temperature performance of TOR rubber asphalt with the rubber powder content above 20%, because TOR rubber asphalt has formed a network structure at this moment.