Warm Mix Agent Research Articles

Fatigue-Healing Performance Analysis of Warm-Mix Rubber Asphalt Mastic Using the Simplified Viscoelastic Continuum Damage Theory

As a green and low-carbon road material, warm-mix rubber asphalt (WMRA) has received extensive attention from scholars for its road performance. In the in-depth study of its properties, the fatigue characteristics of WMRA are particularly critical. However, in current studies on asphalt fatigue performance, its self-healing ability is often underestimated or neglected. Furthermore, the simplified viscoelastic continuum damage theory (S-VECD), with its accuracy, speed, and convenience, provides a powerful tool for analyzing asphalt fatigue performance. Therefore, to analyze the fatigue and self-healing performances of WMRA in practical applications, four sample materials were selected in this study: virgin asphalt mastic (VAM), rubber asphalt mastic (RAM), Sasobit rubber asphalt mastic (SRAM), and Evotherm rubber asphalt mastic (ERAM). Subsequently, the samples were subjected to a comprehensive experimental design with frequency sweep tests, linear amplitude sweep tests, and multiple intermittent loading time sweep tests under different aging conditions. The fatigue and self-healing performances of different aging degrees and different types of WMRA were evaluated based on the S-VECD theory. The results show that aging reduces the fatigue and self-healing performances of asphalt mastic to a certain extent, and at a 7% strain, the fatigue life of SRAM after long-term aging is only 30.7% of the life of the unaged sample. The greater the aging degree, the more pronounced the effect. Under different aging levels, the warm-mix agent can significantly improve the fatigue and self-healing performances of rubber asphalt mastic. After undergoing ten fatigue intermittent loading tests, the recovery rate of the complex shear modulus for the long-term aged VAM was 0.65, which is lower than that of SRAM under the same conditions, and the warm mix can further extend the fatigue life of rubber asphalt by improving the self-healing properties of the asphalt. The role of Sasobit in enhancing the fatigue and self-healing performances of rubber asphalt mastic is more significant. This study can provide a theoretical basis for the promotion and application of WMRA pavements and contribute to the sustainable development of road construction.

Low-temperature performance and micro-structure of warm mix recycled composite aged asphalt

Given the cold winters in Inner Mongolia, the low-temperature performance of asphalt pavement is one of the key factors affecting the service life of roads. This study focuses on commonly used SBS modified asphalt and investigates the coupling effect of adverse factors such as solar radiation, high temperature, and precipitation on road surface asphalt. The objective is offer insights for improving the applicability and service life of warm mix recycled asphalt in cold regions. By using indoor simulation aging equipment, asphalt subjected to hot oxygen aging, composite water aging, and composite ultraviolet aging was prepared to investigate the low-temperature performance of warm mix recycled asphalt. Additionally, to explore the synergistic effect of new asphalt, regenerant, and warm mix agent on the regeneration of aged asphalt, this study analyzes the low-temperature performance and microstructure changes of recycled asphalt through bending beam rheometer (BBR) test, atomic force microscopy (AFM) test, and infrared spectroscopy (FTIR) test. The results show that as the degree of aging increases, the low-temperature crack resistance performance of asphalt deteriorates. Additionally, after the regeneration of aged asphalt, the damping ratio and dissipation energy ratio of warm mix recycled asphalt slightly enhances compared to hot mix recycled asphalt. Furthermore, the incorporation of a warm mix agent enhances the asphalt’s fluidity, viscosity, surface toughness, and further its low-temperature performance. The AFM test results show that the synergistic effect of warm mix agents and regeneration effectively restores the microstructure and surface roughness of asphalt. Moreover, the warm mix agent improves the dispersion uniformity of the SBS modifier in asphalt, helping prevent the agglomeration of asphalt slurry. Qualitative and quantitative analysis of asphalt through FTIR test demonstrates that the mechanisms of warm mix agents and regeneration on new and aged asphalt are a physical process. New asphalt and regeneration supplement the internal lightweight components of aged asphalt, enabling the restoration of most asphalt without affecting the structure of SBS modified asphalt. This project provides a theoretical basis for the engineering applicability of high content warm mix recycled asphalt (composed of 50 % aged asphalt) in large temperature range areas.

The Evaluation and Prediction of Flame Retardancy of Asphalt Mixture Based on PCA-RBF Neural Network Model.

Warm mix flame retardant asphalt mixture can reduce the energy dissipation and harmful gas emissions during asphalt pavement construction, as well as mitigate the adverse effects of road fires. For this, this paper studies the design and performance of a mixture modified with a combination of warm mix agent and flame retardant, and the pavement performance and flame retardancy of the modified mixture are evaluated. Additionally, a flame retardancy prediction model based on the radial basis function (RBF) neural network model is established. On this basis, the principal components analysis (PCA) model is used to analyze the most significant evaluation indicators affecting flame retardancy, and finally, a three-dimensional finite element model is developed to analyze the effects of loading on the pavement structure. The results show that compared to virgin asphalt mixture, the modified mixture shows a reduction in mixing and compaction temperatures by approximately 12 °C. The high-temperature performance of the mixture is improved, while the low-temperature performance and moisture stability slightly decrease, but its flame retardancy is significantly enhanced. The RBF neural network model revealed that the established flame retardancy prediction model has a high accuracy, allowing for precise evaluation of the flame retardancy. Finally, the PCA model identified that the combustion time has a significant effect on the flame retardancy of the asphalt mixture, and the finite element model revealed that the displacements of the warm mix fire retardant asphalt mixture were lower than virgin asphalt mixture in all directions under the loading.

Effect of waste engine oil and warm mix additive on the physical, rheological, and short-term aging attributes of Styrene–Butadiene Rubber-modified asphalt binders

Styrene-butadiene rubber (SBR) latex is used widely to increase the low-temperature resistance of asphalt binders. However, the high content of butadiene copolymer in SBR-treated asphalt causes oxidation and aging. Furthermore, following the SBR modification, the compatibility and thermal storage stability of SBR-modified asphalt is not satisfactory. Therefore, the best approach to improve the quality of short-term aged SBR-modified asphalt is to lower the manufacturing temperatures of the SBR-modified asphalt mixture. In this study, to reduce the preparation temperatures of SBR-modified asphalt mixes and improve their performance after short-term aging, several additives i.e., waste engine oil (WEO), warm mix agent i.e., ZycoTherm, and WEO/ZycoTherm combination (WEO+ ZycoTherm) were selected. The rheological properties and aging performance of binder samples were evaluated through the rational viscosity, dynamic shear rheometer, bending beam rheometer and Fourier transform infrared spectroscopy tests. The results showed that adding WEO together with ZycoTherm into an SBR-modified binder contributed to reducing the compaction and mixing temperatures. The chemical analysis showed that the three additives i.e., WEO, ZycoTherm, and ZycoTherm/WEO declined the aromaticity and chemical aging indicators of aged SBR-modified binders. Furthermore, it was demonstrated that both the ZycoTherm and WEO/ZycoTherm improved the asphalt resistance to rutting at elevated temperatures in both conditions i.e., before and after short-term aging. In addition, the findings revealed ZycoTherm /WEO compound yielded the best performance to improve the minimal-temperature cracking resistance of the SBR-modified binder, resulting in lower short-term aging temperatures. In summary, this study highlights the necessity of lowering preparation temperatures in asphalt mixes containing SBR to enhance binder resistance to rutting and cracking and reduce susceptibility to oxidation during short-term aging.

Synergistic suppressions of porous warm mix agent and composite flame retardant on combustion and fume release of asphalt pavement

The traffic accidents in road tunnel often cause severe fires on asphalt pavement to release a lot of heat and harmful fumes. The composite flame retardant (CFR) containing four environmentally-friendly components was prepared and then loaded on porous warm mix agent (WMA) to prepare flame-retarded WMA (FWA). To reveal synergistic suppression mechanisms on the combustion behaviors of asphalt pavement between CFR and WMA, and among the four flame retardant components in CFR, the effects of FWA and CFR on combustion properties of asphalt mixtures were characterized. Results indicate that WMA has abundant well-developed mesopores or interstitial pores to load small CFR particles, facilitating CFR to play a better flame retarded role. Also, CFR shows obvious suppression effects on asphalt mixture combustion in both gas and condensed phases. FWA efficiently retards asphalt mixture combustion because of synergistic effect between CFR and WMA. Further, FWA has a stronger suppression effect on the combustion intensity of asphalt mixture than CFR. CFR and FWA promote asphalt mixtures to inflate, and catalyze the carbonization reaction of asphalt, increasing residual mass fraction and reducing mass loss rate of asphalt mixture. Finally, CFR and FWA reduce gaseous products, showing obvious fume suppression actions. WMA and CFR synergistically reduce the generation of toxic fume. FWA shows better fume suppression effects than WMA, providing more important opportunity for personnel escape, and reducing environmental pollution.

Effect of warm mix agent on the chemo-mechanical performance of binder with different oil sources

In this study, three typical oil source asphalt binders, Karamay asphalt A, CNOOC 36-1 asphalt B, Qinhuangdao CNPC asphalt C, were selected to prepare asphalt binders together with the warm mix agent Evotherm M1. The effects of warm mix agents on asphalt from different oil sources were experimentally studied via dynamic shear rheological (DSR), thermogravimetric analysis (TG), and Raman spectroscopy tests. The asphalt binders with different oil sources exhibit different properties. The rheological test results indicate that the addition of warm mix agent can slow down the decrease of asphalt viscosity during the aging process and the aging of asphalt. The results of the thermogravimetric test showed that the residual mass of asphalt with the addition of a warm mix agent significantly decreased after aging. Warm mixing agents can slow down the conversion of lightweight components to heavy components during the aging process of asphalt. By calculating the reflectivity of asphalt in Raman spectroscopy, it can be concluded that the reflectivity of asphalt decreases after adding a warm mix agent. The warm mixing agent reduces the degree of thermal evolution of asphalt. Warm mixing agents can make the chemical components in asphalt relatively stable and less prone to further pyrolysis or cracking reactions.

Analysis of the viscosity and self-healing performance of warm-mix recycled asphalt: A method combining molecular dynamics simulations and laboratory tests

The technology of warm-mix regeneration has been frequently used in the production of asphalt pavement; however, the viscosity and self-healing properties of warm-mix recycled asphalt (WMRA) need further study. Therefore, the viscosity and self-healing properties of WMRA were analyzed by combining laboratory tests and molecular dynamics (MD) simulations. First, WMRA with different SWA and reclaimed asphalt pavement (RAP) contents were prepared in the laboratory. Then, different simulations, including viscosity simulation and self-healing simulation and Brookfield Viscosity test, were developed to analyze the performance variation rule. Experimental results showed that the Sasobit warm-mix agent (SWA) significantly reduced asphalt viscosity, and the recycled asphalt’s viscosity increased with asphalt aging deeply. In contrast, the addition of 2% SWA made the viscosity of 100% RAP similar to that of new asphalt. Considering the viscosity reduction effect, asphalt performance and economy, a 3% SWA content is recommended. Both SWA and the degree of aging can reduce the healing performance of WMRA. There is little difference between the two factors in reducing self-healing performance. In general, the study's findings serve as a useful guide for the performance analysis of WMRA.

Study on effect of various rejuvenators on virgin asphalt binders suffering various aging conditions and the unified evaluation index

Adding rejuvenator is a feasible method to restore the properties of aged asphalt. Due to the complex rejuvenation mechanism between different rejuvenators and aged asphalt, there is no unified standard to evaluate the rejuvenation effect of rejuvenator. Most of the current research on rejuvenator focus on the characterization of macro mechanical properties of rejuvenated asphalt binder. In order to explore the changes of chemical composition and micromechanical properties of asphalt during aging and rejuvenation, fifteen kinds of virgin asphalt samples at different aging and rejuvenation stages were prepared. A commercial rejuvenator, aromatic oil and warm mix agent were selected as rejuvenators. The fifteen asphalt samples involved various aging methods, including water-ultraviolet aging, water free ultraviolet aging, RTFOT and PAV. Through gel permeation chromatography (GPC), Fourier transform infrared spectrometer (FTIR) and atomic force microscope (AFM) test, the reversibility evaluation index Rw, RC=O, RS=O and RDMT were proposed. These indexes could be used to quantitatively evaluate the rejuvenation effects of rejuvenator on the specific properties of aged asphalt. Based on the linear fitting results among various indexes, micro reversibility index of virgin asphalt (IRIV) was proposed. The results showed that the commercial rejuvenator and warm mix agent had a limited effect on the recovery of chemical composition and molecular weight of aged asphalt. The commercial rejuvenator over restored the micro mechanical properties of aged asphalt. The effect of aromatic oil on micro mechanical properties of aged asphalt was between commercial rejuvenator and warm mix agent. This study provides a way to quantitatively evaluate the rejuvenation effect of rejuvenator on virgin asphalt binder. It is helpful to better understand the aging-rejuvenation process of virgin asphalt binder more comprehensively from chemical and micromechanical properties.

Investigation of the time-domain linear viscoelastic response of warm mix asphalt mixture via discrete and continuous spectrum

Asphalt mixture is a temperature-sensitive material, and its viscoelastic properties are essential for pavement design and performance evaluation. This paper presents a method for investigating the time domain linear viscoelastic parameter response of asphalt mixture after adding different warm mix agents. The approach utilizes the generalized Sigmoidal function to construct master curves of storage modulus and loss modulus in the frequency domain, and both discrete and continuous spectrum analyses are used to analyze the viscoelastic behavior of the asphalt mixture. The effects of varying Kelvin and Maxwell element numbers on the discrete spectrum are compared to the spectral intensity and master curve obtained from the continuous spectrum. Results show that the generalized Maxwell model with 10−3 or 10−2 as the center point and the generalized Kelvin model with 103 or 104 can obtain more accurate results. When used as input for simulation software, the number of 11 elements can balance computational efficiency and accuracy. The study evaluates the impact of different warm mix agents on the relaxation modulus and creep compliance of asphalt mixture and discusses the practical implications of these findings for engineering applications. Adding Foam warm mix agent significantly lowers the asphalt mixture's relaxation modulus by approximately 44%, while Sasobit and Evotherm marginally raise it by 14% and 22%, respectively. The Foam warm mix agent also increases the equilibrium modulus of creep compliance to 0.091 MPa, 80% higher than that of HMA. The findings of this paper provide guidance for selecting the appropriate warm mix agent to improve pavement performance.

Mechanism of a Warm-Mix Agent and Its Effects on the Rheological Properties and Thermal Stability of Aluminum Hydroxide and Organic Montmorillonite Composite Flame-Retardant Asphalt

Mechanism of a Warm-Mix Agent and Its Effects on the Rheological Properties and Thermal Stability of Aluminum Hydroxide and Organic Montmorillonite Composite Flame-Retardant Asphalt

Catalytic cracking of waste polyethylene into wax-based warm-mix agent for optimizing rheological and mechanical properties of asphalt composites

High value-added transformation of waste polyethylene with low recyclability and slow degradation in nature has become increasingly prevalent. To achieve the viscosity-reducing effect of asphalt, the wax-based warm-mix agents from waste polyethylene were synthesized via a catalytic cracking method, followed by the melt-mixing process of such agent and base asphalt. The effective relationship between chemical composition/structure of warm-mix agents and properties of asphalt composites was established, and the effects of synthesized warm-mix agents on viscoelasticity, rutting resistance and strain recovering ability of asphalt composites were systematically demonstrated. The results showed that the obtained asphalt composites containing 3 wt% warm-mix agents not only exhibited the significantly improved complex shear modulus, rutting factor and recovery percent, but also showed the decreased phase angle and non-recoverable creep compliance, suggesting excellent permanent deformation resistance and high elastic recovery; in addition, the low-temperature properties of resultant asphalt composites might be clearly changed. Moreover, the stiffening effect of the synthesized warm-mix agents was confirmed by the increased amounts of “bee structure” and glass-transition temperature. This work demonstrates that the catalytic cracking product of waste plastics is an economical yet efficient alternative for tuning structure and performance of asphalt.

Experimental Study on Mechanism, Aging and Fatigue Performance of Warm Mixing Speed Melting SBS Modified Asphalt Binders

In this study, two kinds of quick melting modifier SBS-T and SBS-W, as well as the traditional SBS modifier, were used in the optimization design of asphalt binders. The changes in material structure and fatigue properties of three polymer-modified asphalt after adding 3% Sasobit to warm mix agent were investigated. The feasibility of SBS-T and SBS-W in asphalt binder was discussed from the modification mechanism and fatigue properties. In order to reveal the modification mechanism, the interaction mechanism between the fast-melting SBS modifier and the base asphalt was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The temperature sensitivity and viscoelastic properties of SBS-T and SBS-W modified binders were determined by frequency scanning (FS). The fatigue properties of SBS-T and SBS-W modified binders were tested by linear amplitude scanning (LAS). The results of FTIR showed that there was no chemical reaction between the SBS-T and SBS-W and the base asphalt. XRD results showed that SBS-W-modified asphalt has stronger fluidity. The results of FS and LAS showed that the asphalt binder with Sasobit has good stiffness and elastic recovery ability, and the same SBS-T and SBS-W have better temperature sensitivity and deformation resistance. In addition, the fatigue life of asphalt binder under the linear viscoelastic continuous damage theory is increased 3.9 times by SBS-W.

Effect of Sasobit warm mix on micro properties of asphalt with different degrees of regeneration

In this work, an aged asphalt was mixed with a new modified asphalt based on styrene–butadiene–styrene (SBS) in different proportions, and the warm mixing agent was added to simulate the asphalt fusion behaviour in the warm mixed recycled asphalt with different aged asphalt fertilizer (reclaimed asphalt pavement, RAP) content. Low field nuclear magnetic resonance (LF-NMR), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR) were used as analytical techniques to study the role of the warm mixing agent in terms of molecular bond energy, apparent morphology, and functional groups. It was found that the softening point and penetration of asphalt are reduced, and the ductility is increased, during the regeneration process. Sasobit warm mix agent can reduce the penetration and ductility of asphalt and improve the softening point. Its viscosity reduction effect is mainly achieved by adsorbing saturated components and decreasing the bond energy between 1H and other molecules; Sasobit warm mix agent can improve the aging state of mixed asphalt. On the AFM two-dimensional adhesion diagram, the number of bee-shaped structures and the single area is reduced; in the new and old mixed asphalt, the greater the proportion of new asphalt, the more evident the effect of Sasobit warm mix agent is.

Effect of Organic Viscosity-Reducing Warm-Mix Agent on the Performance of Rubber Asphalt

Dynamic mechanical analysis (DMA) and other evaluation methods were used to investigate the effect of WS-1, an organic viscosity-reducing temperature mixing agent, on the rheological and conventional properties of warm-mix rubber asphalt (WMRA). The results demonstrated that the WS-1 warm-mix agent exhibited an excellent viscosity-reducing effect and that, with the increasing of WS-1 content, the high-temperature viscosity of the WMRA decreased significantly. The viscosity and softening point of the WMRA increased at 60 °C simultaneously, with the softening point increasing by about 15 °C. The penetration and ductility decreased by about 1 mm and 6 cm, respectively, and the activation energy (Eη) and temperature sensitivity increased. These results indicated that WS-1 could improve the high-temperature performance of WMRA but had an adverse effect on its low-temperature performance. Upon using temperature scanning for the WMRA, the addition of WS-1 significantly increased the rutting factor (G*/sin δ) of the WMRA and greatly improved its rutting resistance within the temperature range examined. The addition of WS-1 changed the viscosity of WMRA, thus affecting the hot-storage stability of WMRA at high temperatures.

Rheology and volatile organic compounds characteristics of warm-mix flame retardant asphalt

Warm-mix flame retardant asphalt (WF-A) is widely used in tunnel pavement owing to its positive construction and workability, as well as excellent flame retardant performance. When flame retardant (FR) improves the flame retardancy of asphalt binders and warm mix agent reduces the construction temperatures, the combined effects of the two additives on asphalt binders’ performances need to be studied. In this study, through orthogonal experimental design, limiting oxygen index (LOI) test and viscosity test, the optimum WF-A was selected. Afterward, the service performances of WF-A were comparative analyzed with warm mixing asphalt, SBS modified asphalt and flame retardant asphalt, including construction temperatures, high-temperature rheological property and aging resistance. Additionally, the characteristics of volatile organic compounds (VOC) emission are assessed by gas chromatography mass spectrometry (GC–MS). The results show that the optimum WF-A is that with the content ratio of 3.5% EC-120 and 8% FRMAX under the mixing temperature of 150 °C, and warm mix agent (EC-120) can obviously reduce the high-temperature viscosity of SBS modified asphalt binder, and increase the high-temperature fluidity; flame retardant (FRMAX) adversely affects the viscosity reducing effect of EC-120. The additions of the two additives are not conductive to the aging resistance of asphalt. Besides, both EC-120 and FRMAX have the effect of reducing asphalt fumes, and the optimum WF-A can reduce VOC emissions by 45.5% compared with SBS modified asphalt binder. The study provides significant references for further applying WF-A in the sustainable and safe construction of road networks.

Influence of Warm-mix Agent on Compaction Quality of SMA-13 at Low Temperature

Influence of Warm-mix Agent on Compaction Quality of SMA-13 at Low Temperature

Characterization of Warm Mix Agent and Its Influence on Properties of SBS-Modified Asphalt

Warm mix agent is the key factor to restrict the performance of warm mix asphalt. In this paper, methods of X-ray diffraction, thermal stability test, and laser particle size analysis were used to test and analyze the internal structure, composition, and properties of three kinds of warm mix agents. In order to study the performance impact of the warm mix agent on SBS-modified asphalt, the warm mix agents of Advera®, LTA synthetic zeolite, and 13X synthetic zeolite were added to SBS-modified asphalt in different contents. The three kinds of warm mix asphalt were tested by the experiments of softening point, penetration, and ductility to analyze their physical properties. The testing results showed that the softening point of three kinds of warm mix SBS-modified asphalt is greater than the softening point of SBS-modified asphalt without adding warm agents, which indicate the warm mix additives can improve the high-temperature stability of SBS-modified asphalt. The three kinds of the warm mix agent make SBS-modified asphalt hard, and the consistency and the ability of resisting deformation increase. The low temperature performance of SBS-modified asphalt decreased in different degrees with mixing different zeolite warm mix agents.

Effect of Warm Mix Agent on Physical and Aging Properties of Crumb Rubber Modified Bitumen

The effects of modified natural zeolite warm mix agent (MNZWMA) and organic viscosity reducing warm mix agent (OVRWMA) on the physical properties, short term thermal oxidation aging, long term thermal oxidation aging and UV aging properties of the crumb rubber modified bitumen (CRMB) were investigated. The results showed that MNZWMA and OVRWMA could improve the high temperature stability and the low temperature crack resistance of CRMB, respectively. During the short term thermal oxidation aging, long term thermal oxidation aging and UV aging, OVRWMA increased softening point increment (SPI) and viscosity aging index (VAI) of CRMB, however, MNZWMA decreased its SPI and VAI. The analysis of FTIR spectra indicated that MNZWMA reduced the formation of carbonyl groups and sulfoxide groups, but OVRWMA accelerated the formation of carbonyl groups and sulfoxide groups to some extent during ultraviolet aging. Therefore, MNZWMA could improve the anti-aging properties, and OVRWMA was not conducive to the anti-aging properties of CRMB.

Estimation and Analysis of Energy Conservation and Emissions Reduction Effects of Warm-Mix Crumb Rubber-Modified Asphalts during Construction Period

In order to solve the serious environmental problems caused by the rapid increase in the number of waste tires and unproper storage of waste tires, modifying the asphalt mix for roadway pavement by adding rubber crumb from recycled waste tires is one of the highly effective approach to solve the problem and can achieve the sustainable use of rubber resources. The application of warm-mix crumb rubber-modified asphalt (CRMA) overcomes some issues of the hot-mix CRMA, such as high temperature and high energy consumption. However, there is a lack of estimation methodology for the energy conservation and emission reduction during the production process of warm-mix CRMA. This study develops the estimation models for the evaluation of energy conservation and emissions reduction during different production stages of waste rubber powder, asphalt, CRMA, hot-mix CRMA, and warm-mix CRMA. A list for gas emissions during the mixing and paving process of CRMA mixtures was established through the simulated mixing measurement and paving site measurement. The results show that for each metric ton of CRMA mixture produced, warm mixing can reduce energy consumption by 18~36% and decrease gas emissions during different stages by 15~87% compared to hot mixing. The Evotherm warm-mix CRMA mixture with DAT as warm mix agent (Ev-DAT warm-mix CRMA mixture) is more energy-efficient by saving approximately 108.56 MJ of energy and reducing gas emissions during mixing and paving by at least 32% and 73%, respectively. This model can improves the technical standard of warm-mix CRMA and the energy conservation assessment.

Static and dynamic mechanical properties of warm mixed asphalt mixture before and after aging

In order to study the effect of warm mix agent on the mechanical properties of warm mix asphalt mixture before and after aging, this article uses the uniaxial compression test and the uniaxial dynamic modulus test which were carried out on the unaged, short-term aging and long-term aging conditions of the matrix and SBS modified asphalt mixture mixed with RH and Evotherm warm mix agent respectively. The results show: the performance of each asphalt mixture at low temperature and high frequency is equivalent, indicating that dynamic mechanics is not suitable for evaluating the low temperature performance of asphalt mixture; high temperature and low frequency can be used as an evaluation index for high temperature anti-rutting of asphalt mixture. By analyzing the rebound modulus, uniaxial dynamic modulus and other results, it shows that the addition of the warm mix agent improves the low temperature performance of the asphalt mixture, alleviates the aging of the asphalt mixture, and the aging of the aging also brings about a decrease in high temperature stability. The beneficial effect of the Evotherm is weak, and the low temperature performance of the asphalt mixture after aging and the high temperature stability of the warm asphalt mixture after long-term aging are improved. From the comprehensive analysis of static and dynamic mechanical properties, the elastic modulus and dynamic modulus of asphalt mixture are not much different, and the dynamic static modulus of the mixture after aging is quite different, which provides a theoretical basis for the dynamic and static modulus transformation.