Viscosity Of Asphalt Research Articles

СТІЙКІСТЬ ДО РОЗТРІСКУВАННЯ АСФАЛЬТОБЕТОНУ, НАСИЧЕНОГО ДОРОЖНЬОЮ СІЛЛЮ, ПРИ ЗАМОРОЖУВАНІ

The article deals with issues of resistance to cracking at low temperature, low-temperature characteristics of asphalt concrete, tensile strength in bending, and the ratio of tensile strength to bending deformation, which reflects the flexibility of asphalt concrete.When the temperature is relatively low, the asphalt concrete should have a certain deformation capacity, and the temperature shrinkage crack can be reduced under the low temperature condition. The ultimate flexure tensile strain at low temperature is closely related to the performance of asphalt. Increasing the viscosity of asphalt can improve the low-temperature crack resistance of pavement

Applying solution of spray polyurea elastomer in asphalt binder: Feasibility analysis and DSR study based on the MSCR and LAS tests

Abstract The polyurea elastomer (PUA) powder modifier was prepared by the method of spraying–initial crushing–fine grinding, and then, the PUA-modified asphalt was produced. The typical functional structure of PUA was identified and characterized. The apparent viscosity of PUA-modified asphalt was tested at different temperatures. The impact of particle size and content of PUA on creep and recovery properties of asphalt at high temperature was investigated through the multiple stress creep recovery test. The mesothermal fatigue behavior of PUA-modified asphalt was evaluated by means of time sweep and linear amplitude sweep. Results indicated that the high elastic properties of PUA materials might depend on the spherical structure inside PUA material. The diameter of functional structure was around 20 µm and presented as 3D ball structure. The increase in PUA particle size would lead to the increase in cracks and folds in the bonding surface PUA modifier could improve by about 50% of the apparent viscosity significantly. Furthermore, PUA modifier could promote the high-temperature rutting resistance and middle-temperature fatigue property of asphalt. The improving effect on R could reach almost 28% and the 0.075 mm could be the best application size of PUA.

Characterizing ZSV of SBS modified asphalt using shear rate sweep test and frequency sweep oscillation test

The Zero-shear viscosity (ZSV) of asphalt is frequently measured using shear rate sweep test (η) or frequency sweep test (η*), whose correlation is often established via the cox-merz rule. However, the applicability of cox-merz rule upon SBS modified asphalt (SBSMA) is still debatable. This study aims to characterize ZSV of SBSMA using both shear rate sweep test and frequency sweep test and examine the cox-merz rule for SBSMAs with different SBS contents. The testing temperature is fixed at 60 °C and to enlarge the η* testing frequency range, master curve is created based on a novel double sigmoidal model. Results indicate that cox-merz rule is valid for plain asphalt but not for SBSMA, and the deviation is more evident for highly modified SBSMA (the deviation increases from 0.8 % to 13.2 %). Based on Kramers-Kronig relations, SBSMA must be pure viscous (phase angle δ = 90°) to obtain a strict η* plateau for ZSV measurement, which is quite difficult because SBSMA can only be pure viscous above the SBS polymer glass transition temperature (100 °C). Therefore, it is theoretically impossible to obtain an SBSMA η* plateau at 60 °C that resembles the η plateau, hence the cox-merz rule fails. A η* Newtonian plateau was observed in the master curve, but it was obtained at temperatures higher than 100 °C and cannot be used for 60 °C ZSV measurement either. With reduced frequency, the η* master curve of SBSMA shows 4 stages including a “pseudo-plateau”. The pseudo-plateau should be treated with care and cannot be used for ZSV measurement.

Preparation and performance evaluation of rubber powder-polyurethane composite modified cold patch asphalt and cold patch asphalt mixture

Considering the unfavorable stability and insufficient strength of cold patch mixtures used in pavement pothole repair at an early age, 80 mesh waste rubber powder and polyurethane were selected for composite modification of #70 base asphalt, in which the contents of the two modifiers were determined through parallel tests with basic performance indexes of asphalt being employed as the criteria for evaluation. The modified asphalt was diluted with XSJ-1, a self-made composite diluent, and the preparation process of cold patch asphalt, as well as the cold patch asphalt formula, were defined. Based on DSR, DSC and FTIR tests, the performance of the composite modified cold patch asphalt was evaluated, and the modification mechanism was analyzed. The cohesion, strength, high-temperature stability, and moisture susceptibility of the cold patch asphalt mixture were evaluated with two types of commercially available cold patch asphalt mixtures as the comparison. The outcomes demonstrate that the qualities of waste rubber powder/polyurethane composite modified cold patch asphalt are significantly superior to those of single modified cold patch asphalt. The viscosity of cold patch asphalt is remarkably influenced by the quantity of diluent employed. It is recommended that base asphalt contain 10 % and 7 %, respectively, of waste rubber powder and polyurethane with a diluent of 25 %. The initial strength and formed strength of the composite modified cold patch mixture were considerably higher than those of the control cold patch mixtures, and the time needed to reach the formed strength was shortened by 2 days.

Effect of basalt fiber on properties of asphalt and asphalt mixture

Asphalt mixture is the surface material of flexible pavement and semi-rigid pavement. It directly bears the influence of climate conditions and traffic load, and is prone to aging and fatigue damage. Therefore, using reinforcing agent to improve the performance of asphalt mixture is the long-term goal of researchers.This paper aims to study the effect of basalt fiber on asphalt viscosity and mechanical properties of asphalt mixture. Firstly, by testing the basic properties of asphalt binder with different fiber content, the viscosity characteristics of fiber + asphalt composites are analyzed by using the modified Einstein viscosity equation. The research shows that basalt fiber has obvious toughening effect on asphalt, and the penetration and softening point indexes are suitable to evaluate the viscosity properties of fiber + asphalt composites.Secondly, the effects of different fiber content on the water stability and splitting tensile strength of asphalt mixture are analyzed. The results show that the maximum content of basalt fiber should not be greater than 0.4%; With the increase of fiber content, the splitting strength of asphalt mixture increases, but the increase is not obvious when the content is > 0.30%, while the stiffness modulus continues to increase, indicating that the deformation resistance of asphalt mixture is enhanced after adding fiber. Based on the micromechanics theory of composite materials, the basic principle of basalt mineral fiber improving the strength performance of asphalt mixture is explained. The research shows that basalt mineral fiber can significantly improve the performance of asphalt mixture.

Research and Measurement Status and Data Processing Technology of Highway Asphalt Intelligent Testing Equipment

This paper introduces the current status of the asphalt viscosity testing equipment in the field of the road engineering, domestic and foreign study about the high viscosity standard that is used for the calibration of such equipment, as well as the developing technologies of the viscosity standard; it also predicts and gives the outlook about the development trend of the high viscosity standard in the future.

Aging resistance of polyurethane/graphene oxide composite modified asphalt: performance evaluation and molecular dynamics simulation

ABSTRACT To evaluate the effect of polymers and nanomaterials on asphalt after thermo-oxidative aging, the aging resistance of thermoplastic polyurethane modified asphalt (PU-MA), polyurethane/graphene oxide composite modified asphalt (PU/GO-MA) were discussed through experiments and molecular dynamics (MD) simulations. The molecular composition and self-healing ability of aged asphalt were investigated. Base asphalt and virgin asphalt were used as control. The aging experiments of base asphalt, PU-MA and asphalt modified with PU and different content of GO composites were carried out by rolling thin-film oven test. The differential scanning calorimeter, thermal gravimetric analyzer, viscous flow deformation, bending beam rheometer and Fourier transform infrared spectrometer tests were carried out. The molecules and cracks models of asphalt were simulated by MD. The parameters such as mean square displacement, fractional free volume, dipole moment and viscosity were calculated. The results show that PU/GO can affect the transformation among components, increase the melting temperature of asphalt, improve the migration ability of asphalt molecules, enhance the self-healing diffusion movement of asphalt molecules and reduce the energy and viscosity of aged asphalt. In brief, nano and chemical synergistic modification has effects on the properties of asphalt after aging.

Modification and enhancing effect of SPUA material on asphalt binder: A study of viscoelastic properties and microstructure characterization

In order to significantly improve the viscoelasticity and durability of asphalt materials, Spray polyurea (SPUA) resin modified materials with different particle sizes were obtained by low-temperature fine grinding process in this study, and the corresponding SPUA modified asphalt was prepared. The basic properties of resin modified asphalt were compared and analyzed. The influence of SPUA resin modification materials on the apparent viscosity of asphalt was analyzed. Through dynamic shear rheometer (DSR) and bending beam rheometer (BBR) test, the effect of SPUA resin material on rheological properties of asphalt was systematically investigated. Furthermore, the modifier and asphalt binder were characterized by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Results show that decreasing the particle size or increasing the dosage of the SPUA modifier could improve the softening point and apparent viscosity and reduce the ductility, which indicate SPUA modifier could improve the high temperature shear resistance and elastic recovery performance of asphalt binder. The SPUA modifier with smaller particle size has better high temperature rheological modification effect and less negative effect on low temperature performance deterioration. Although part of the functional spherical structure was damaged, the 0.075 mm SPUA modifier could closely interact with the base asphalt perfectly. This study would provide the scientific references for the application of Spray polyurea resin materials in the field of asphalt pavement materials.

Study on Performance and Mechanism of SBR and Bio-Oil Recycled SBS Modified Asphalt

With the continuous development of road construction and maintenance, SBS(Styrene-butadiene-styrene)-modified asphalt is widely used. However, there is no mature method for restoring aged SBS-modified asphalt. This study proposes the use of SBR(polymerized styrene butadiene rubber) and bio-oil for the restoration of aged SBS. In this study, five kinds of recycled asphalt were prepared by adding 5% bio-oil, 10% bio-oil, 6% SBR, 6% SBR + 5% bio-oil, and 6% SBR + 10% bio-oil to long-term aged SBS-modified asphalt. Softening point, penetration, and rotational viscosity experiments were tested to evaluate the conventional properties. Rheological tests revealed the performance of asphalt. Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM) tests were tested to demonstrate the microscopic characteristics of asphalt. Conventional tests investigated that aged asphalt viscosity will increase. Bio-oil could well recycle the asphalt viscosity. SBR could also soften aged asphalt, but its modification effect is limited compared with bio-oil. Rheological tests presented that the SBR and bio-oil have little impact on the temperature sensitivity of SBS-modified asphalt. SBR and bio-oil could decrease the asphalt stiffness. However, SBR and bio-oil could ameliorate the anti-cracking behavior of aged asphalt. The microscopic tests exhibited that SBR and bio-oil could decrease the asphaltene and colloid. Meanwhile, bio-oil could supplement alcohols and ethers at wave number 1000 cm-1-1270 cm-1. Alcohols and ethers are hard to oxidize, something which has a beneficial role in the anti-aged of recycled asphalt.

Aging Characterizations of Modified Asphalt Binders Based on Low Field Nuclear Magnetic Resonance (LF-NMR).

Styrene-butadiene-styrene block copolymer (SBS) and crumb rubber modifier (CRM) are commonly used modifiers to modify asphalt binders. The aging of modified asphalt binders is an important factor affecting their performance. In this paper, the effects of the two modifiers (i.e., SBS, CRM) on the aging of modified asphalt binders were studied by using low field nuclear magnetic resonance (LF-NMR) technology and dynamic shear rheological (DSR) tests. Test results showed that when T2, a parameter of relaxation time from NMR test, was within 2.2 milliseconds, the relaxation peak of both modified and unmodified asphalt binders tested showed two peaks (i.e., "M" shape), and when it was greater than 2 milliseconds, extra peaks appeared only in the modified asphalts. These extra peaks gradually disappeared with increased aging; the modifiers carried signal intensities of their own. The addition of a modifier changes the law of "the greater the viscosity of asphalt, the shorter the T2 relaxation time". With the aging process, the normalized peak area (NPA) from NMR decreased, and rutting resistance factor from DSR increased. However, the NPA of modified asphalt increased after the PAV test, which may be related to the change of H semaphore. The rheological properties of the asphalt binders before and after aging were well-correlated with the NPA of T2.

Effect of graphene oxide in different phases on the high temperature rheological properties of asphalt based on grey relational and principal component analysis

Nanomaterials such as graphene oxide (GO) are frequently applied in electronic, biological, and environmental areas, among others. In recent years, GO has also been increasingly used in pavement engineering. In this study, two different states of GO (solid and dispersant) were used as modifiers of asphalts to determine which might be the better modifier. They were mixed with base asphalt and styrene–butadienestyrene (SBS) modified asphalt to produce GO modified asphalt and GO/SBS modified asphalt. The storage stability and high temperature rheological characteristics of asphalt were tested using a softening point meter, Brookfield viscometer, and dynamic shear rheometer (DSR). Grey relation analysis (GRA) and principal component analysis (PCA) were used to evaluate the experimental data. According to the experimental findings, adding GO can significantly increase asphalt's viscosity and storage stability. In addition, the inclusion of GO can make asphalt more elastic and increase its resilience to deformation brought on by temperature changes and stress. Through experiments, several indicators that define asphalt's high temperature performance were measured. Two indicators with the best correlation with rutting resistance of asphalt were selected by grey relation analysis: phase angle (δ) and irrecoverable creep compliance (Jnr), which are more representative for assessing the effectiveness of asphalt's rutting resistance. Using these parameters, a comprehensive score for the asphalt's high temperature performance was generated using principal component analysis. Our results indicate that adding GO can significantly raise asphalt's overall rating. The composite scores of the base asphalt modified by the liquid GO dispersion and the SBS modified asphalt were −1.39 and 2.12, respectively, while those modified by solid GO were −1.58 and 2.05, respectively. This shows that GO dispersion offers better modification effects. Our findings demonstrate that the high temperature performance of the composite modified asphalt prepared by adding the GO dispersion to the SBS modified asphalt provides the best comprehensive scores of all asphalts.

Analysis of fracture morphology of asphalt concrete under different temperatures

By studying the fracture morphology of splitting failure and bending failure of asphalt mixture under different temperatures, it is confirmed that temperature has an impact on the micro mechanism of asphalt mixture fracture. The fracture at low temperature is relatively flat, the fracture of aggregate and asphalt aggregate interface account for a certain proportion, and the failure of asphalt mixture is mainly brittle fracture; With the increase of temperature, the fracture surface becomes rough, and the fracture of asphalt mortar layer is mainly; The addition of rubber powder improves the viscosity of asphalt and the bonding strength of asphalt mortar, greatly improves the fracture ratio of aggregate and interface area, and improves the crack resistance of asphalt mixture; The fracture morphology of asphalt mixture specimen better reflects its mechanical characteristics.

Using SBS/terpene‐styrene resin blends as a novel high‐viscosity asphalt modifier

AbstractTo improve the inferior stability in high‐viscosity asphalt prepared using styrene‐butadiene‐styrene block copolymer (SBS) and to simplify the preparation process, a novel high‐viscosity modifier (STP) was prepared with SBS, terpene‐styrene resin (TSR) and plasticizer. Its inherent properties, optimal dosage, and modification effect were investigated. The results show that STP has lower component melting temperature and stronger polarity, combined with good thermal stability, ensuring that STP possesses a better modification effect on asphalt. 14.5–17.6 wt% was determined as the appropriate content of STP. The incorporation of STP improved the rutting resistance and elasticity percentage of the asphalt. The zero shear viscosity (ZSV) of asphalt fitted by the Carreau model showed that STP increased the cohesion of the asphalt system and improved the high‐temperature deformation resistance. The small non‐recoverable creep compliance value proves that the STP high‐viscosity asphalt (STP‐HVA) exhibits excellent resistance to permanent deformation at high‐temperatures while displaying low‐stress sensitivity and achieving an extremely heavy traffic rating. STP confers greater flexibility to asphalt to eliminate low‐temperature cracking phenomenon. Smaller CMAI and PAAI values demonstrate that STP‐HVA exhibits outstanding aging resistance. TSR effectively improves the compatibility of SBS and base asphalt, and STP particles are finely dispersed and uniform. The preparation process is mainly physical modification, accompanied by chemical reactions.

Zero Shear Viscosity of Hybrid Modified Asphalts and Its Gray Correlation with Other Properties.

The viscosity of modified asphalt binders is the most important property to ensure the durability of open-graded friction course (OGFC). Zero shear viscosity (ZSV) is considered to be the optimum result to reflect the rutting characterization of high viscosity modified asphalt binders, compared with conventional vacuum capillary viscosity. However, there are few reports on using ZSV to evaluate the material characteristics of hybrid modified asphalt binders and to establish the relationship between ZSV and other properties. In this paper, a high viscosity hybrid modified asphalt binder was prepared with Sty-rene-butadiene-styrene (SBS) and Crumb rubber modifier (CRM). ZSV, three major indicators, 60 °C dynamic viscosity, 135 °C Brookfield viscosity, and a dynamic rheological test were used to determine the properties of the hybrid modified asphalt binders. The relationship between ZSV and other properties was studied by the gray correlation analysis method. Results indicated that: (1) The viscosity of hybrid modified asphalt binders increases with the decreasing frequency. When the frequency tends to 0, the viscosity of asphalt at this time is zero shear viscosity; (2) The values of the ZSV of hybrid modified asphalt binders have a large increase as the dose of both CRM and SBS modifiers were increased; and (3) The ZSV at 60 °C correlated well with the performance properties of rutting factor (G*/sin(θ)), indicating that the ZSV of hybrid modified asphalt binders could be a good indicator of performance.

Study on rheological properties of warm mix large proportion recycled asphalt

In order to explore the rheological properties of high content warm mix recycled asphalt binder, recycled asphalt was added into warm mix asphalt to prepare warm mix recycled asphalt. The optimum content of regenerant and Sasobit REDUX was determined by asphalt basic performance test and temperature scanning test. The chemical composition of recycled asphalt was studied by FITR. The rheological properties and low temperature crack resistance of warm mix recycled asphalt were analyzed by DSR and BBR tests, and the optimum content of recycled asphalt was determined. The results show that when the content of regenerant is 10%, its basic performance recovers to the level of base asphalt. Sasobit REDUX can reduce the high temperature viscosity of asphalt, and the optimum content is 1%. With the increase of recycled asphalt content, the shear modulus and phase angle of warm mix recycled asphalt gradually decrease, and its high temperature stability gradually increases. Under low frequency and high temperature conditions, warm mix recycled asphalt with 50% content has better high temperature deformation resistance. Under the action of stress, the strain accumulation decreases with the increase of the content of recycled asphalt. When the content of recycled asphalt is 50%, the ability of warm mix recycled asphalt to resist load deformation and temperature sensitivity in the middle temperature zone is similar to that of matrix asphalt, and it has good deformation resistance and low temperature crack resistance. Comprehensive analysis of the best content of recycled asphalt should be 50%, then warm mix recycled asphalt mixture has excellent road performance.

Evaluation and molecular interaction of asphalt modified by rubber particles and used engine oil

This study investigates the molecular mechanism of used oil on improving the compatibility and viscosity reduction of rubberized asphalt (RA) using molecular simulations and lab tests. This validates the feasibility of producing waste oil modified RA while enhancing the sustainable use of resources and pavement performance. The model of RA with used oil was first built by Materials Studio software. Several molecular dynamics parameters were used to explore the molecular behavior, stability and viscosity of asphalt. Furthermore, the relevant experiments were employed to validate the results of molecular simulation. The results show that used oil molecules can promote the dispersion of macromolecules, including asphaltenes, resins and rubbers, making the system more in accord with the asphalt colloid theory. It supplements the light components in the system to provide a stable dispersion medium. FTIR spectra confirm the rubber activation with used oil and microwave radiation. The softening point difference of RA was reduced from 1.9 to 0.35 °C. Viscosity was even reduced by approximately 67.1%.

Study on multiple Damage-Healing properties and mechanism of laboratory simulated recycled asphalt binders

• The laboratory simulated recycled asphalt was prepared using indoor aging test. • The fatigue behavior of recycled asphalt after multiple damage-healing was tested. • Links of self-healing index with physicochemical features of asphalt were established. In order to solve the fatigue cracking problem in asphalt binder reuse, recycled asphalt was prepared in the study by mixing indoor aged SBS modified asphalt and original SBS modified asphalt, which provides a reference for the damage-healing mechanism when recycling asphalt binder in road engineering. The application feasibility of laboratory simulated recycled asphalt was determined by Brookfield viscosity tests; Dynamic Shear Rheometer (DSR) test was conducted to explore the multiple damage-healing behavior of laboratory simulated recycled asphalt; Fourier Transform Infrared Spectroscopy (FTIR) test, Thermal Gravimetric Analyzer (TGA) test and Gel Permeation Chromatography (GPC) test were used to reveal the intrinsic mechanism of changes in the healing potential of laboratory simulated recycled asphalt. The results show that the viscosity of asphalt is less than 3.0 Pa·s except for PA 100%; the incorporation of aged asphalt increases the temperature sensitivity of laboratory simulated recycled asphalt, and the power function is more accurate than Saal's equation in expressing the viscosity-temperature relationship of asphalt. The times of damage-healing significantly affect the self-healing ability of asphalt, the degree of influence is greater than the healing time, and the decrease in mobility is the macroscopic factor of the weakened healing ability of asphalt. Meanwhile, microscopic test results show that with increasing aging asphalt contents and deepening aging degree, the aromatic ring index (I C=C ) of laboratory simulated recycled asphalt, the initial degradation temperature (IDT), the final residue (FR), and the number of macromolecules such as gum and asphaltene increases, which hinders the flow and diffusion between asphalt molecules and slows down the crack healing. Therefore, the recycling of aged asphalt is an effective way to achieve the sustainable use of asphalt binder, but the content of admixtures should be controlled in a relatively low range to ensure its workability and reduce its impact by early cracking.

Research on Rejuvenation of Styrene-Butadiene-Styrene Block Copolymer Modified Asphalt with Rejuvenating Agent Based on Pre-Mixing Method

The traditional addition method of rejuvenating agent used in the laboratory is inconsistent with the actual situation of the project, which reduces the reliability of the test results. In this paper, the way of premixing rejuvenating agent and Reclaimed Asphalt Pavement (RAP) and extracting asphalt binder is selected, and the modification effect, mechanism, and optimal content of rejuvenating agent on Styrene-Butadiene-Styrene Block Copolymer (SBS) modified asphalt are studied. In this paper, the asphalt in RAP is recycled and restored with different content of regenerant, and the conventional technical performance and Performance Graded (PG) grade of regenerated asphalt was tested. The composite equation of regenerated viscosity of SBS-modified asphalt was analyzed, and the pavement performance of regenerated SBS-modified asphalt mixture with different content of rejuvenating agent and RAP was tested, such as high-temperature stability, low-temperature crack resistance, and water stability. Finally, the determination method of the optimal content of rejuvenating agent was discussed. The results show that it is reliable to predict the viscosity, penetration, and softening point of regenerated asphalt by viscosity logarithmic composite equation. The content of rejuvenating agent has a certain influence on the PG classification of SBS-modified asphalt, which is mainly reflected in the low-temperature critical temperature. There is a certain content of rejuvenating agent to make the high-temperature stability of regenerated SBS-modified asphalt mixture reach the maximum. When the content of rejuvenating agent reaches a certain value, the low-temperature crack resistance and water stability of regenerated SBS-modified asphalt mixture no longer increase significantly with the increase of the content of regenerant. Using the three-level determination method of the optimal content of rejuvenating agent proposed in this paper, the optimal content and reasonable content range of rejuvenating agent can be obtained, which makes the technical performance of regenerated asphalt, PG grade, and the pavement performance of regenerated SBS-modified asphalt mixture meet the specification requirements.

A Study of Foam Bitumen Preparation for Effective Recycling of Pavement Layers

Foamed asphalt recycling technology can effectively recover waste asphalt pavement materials and achieve the sustainable utilization of resources. This technology’s core equipment is asphalt foaming equipment. Since the asphalt foaming device’s fault data are uncertain, this work proposes a method for evaluating the device’s reliability, combining triangular intuitionistic fuzzy numbers, trapezoidal intuitionistic fuzzy numbers, and expert knowledge. Using the proposed evaluation method, the failure probability of the asphalt foaming device and the importance of the bottom event were calculated. The obtained model results were found to be consistent with the actual collected data, verifying the reliability and validity of the model. Furthermore, the asphalt viscosity is one of the key factors affecting the asphalt foaming recycling technology. In this work, the influence of different viscosities on the asphalt foaming mechanism was investigated using a theoretical analysis. Then, a computational fluid dynamics (CFD) analysis method was employed to simulate the different viscosity asphalt foaming processes, aiming to identify the most suitable one for the production of high-quality foam asphalt in the foaming asphalt viscosity range. Finally, experiments were carried out to verify the results of the analysis. The results show that the asphalt foaming device’s failure probability was around 7.512 × 10−2, and the best foaming asphalt viscosity was in the range of 0.3~0.5 Pa·s.

High-Temperature Rheological Properties of Crumb Rubber Composite Modified Asphalt

As a kind of environmentally friendly material, crumb rubber modified asphalt is widely used in highway engineering to accelerate the consumption of end-life tires. The objective of this study is to investigate the high-temperature rheological properties of crumb rubber composite modified (CRCM) asphalt. In this study, the same content of crumb rubber and different content of composite additives were added to prepare the CRCM asphalt, including CRCM-SBS, CRCM- Sasobit/BRF, and CRCM-RARX. The viscosity, phase angle, rutting factor, critical temperature, storage modulus, non-recoverable creep compliance, percent recovery, stress sensitivity, and the functional groups of all testing specimens were obtained by the rotational viscometer, dynamic shear rheometer, multiple stress creep recovery, and Fourier transform infrared spectroscopy tests to evaluate the high-temperature rheological properties of asphalt. In general, the results were favorable for enhancing the high-temperature performance and reducing the stress sensitivity of asphalt. It showed that the incorporation of crumb rubber and additives increased the viscosity of asphalt under different testing conditions. Additionally, the addition of crumb rubber and additives in the base asphalt could be used to increase elastic components and improve the permanent deformation resistance, and the performances are closely related to the types of additives. Thus, considering the high-temperature performance, the asphalt modified by crumb rubber and RARX additive was recommended to apply to asphalt pavement.