Rheological Properties Of Asphalt Research Articles

Construction and examination of temperature master curve for asphalt with different aging extents

Master curve is widely applied to assess the rheological properties of asphalt. The traditional master curve describes the variation of asphalt rheological properties with frequency. However, compared to frequency, the influence of temperature on asphalt properties is of greater concern. This study attempted to establish a method to transform the traditional master curve into temperature master curve. To this end, asphalt binder with different aging extents were prepared using aging simulation tests, and traditional complex shear modulus master curves of asphalt binder were established based on frequency sweep test. These were then transformed into temperature master curves using the established temperature-frequency equation. Furthermore, the accuracy of the temperature master curve was assessed through temperature sweep tests. The results showed that the temperature-frequency equation obtained based on Williams Landel Ferry equation effectively described the relationship between temperature and reduced frequency. The temperature master curve demonstrated good applicability for asphalt at different aging levels, with the differences between complex shear modulus values calculated by temperature master curve and the experimental values generally within 20%. The temperature master curve accurately characterized the trend of complex shear modulus with temperature. However, this accuracy and applicability were primarily focused on the mid-temperature and high-temperature ranges. The temperature master curve had obvious deficiency in predicting the complex shear modulus at low temperature. The findings provide new methods and insights into the relationship between asphalt rheological properties and temperature.

Tuning high- and low-temperature rheological properties of warm-mixing asphalt composites by functionalized waxes

Traditional asphalt road construction utilizes hot-mixing asphalt mixtures. High temperatures not only accelerate the aging of asphalt, but also produce large amounts of toxic and greenhouse gases. To alleviate these problems, wax-based warm-mixing agents are applied, and asphalt pavement construction temperatures can be efficiently lowered, resulting in lower energy and gas emissions. To systematically evaluate the effects of composition and structure of warm-mixing agents on rheological properties of asphalt at high and low temperatures, a series of functionalized waxes (i.e., oxygen-containing groups, amide groups, and long-chain aliphatic hydrocarbons) were designed in this work, followed by a melt-mixing process with asphalt. The findings demonstrated that warm-mixing agents with long-chain aliphatic hydrocarbons could significantly improve asphalt composites’ rheological properties at high temperatures, such as good viscosity-reducing effect and superior rutting resistance or permanent deformation resistance; warm-mixing agents with oxygen groups were able to improve the asphalt composites’ resistance to low-temperature cracking; amide group-containing warm-mixing agents could improve the surface roughness of asphalt composites. This work provides a practical guide for the selection of functionalized warm-mixing agents for asphalt pavement under multiple environmental factors.

Rheological properties of warm mixed high viscosity asphalt at high and low temperatures.

The rheological properties of asphalt can well reflect its road performance, but the rheological properties of warm mix high viscosity asphalt (HVA) are unclear. In order to study the effect of warm mixing agent on rheological properties of HVA, two kinds of warm mixing agent EC120 (EC) and Evotherm M1 (M1) were selected to prepare warm mix HVA. The rheological properties of warm mix HVA at high temperature (135~195°C), medium temperature (0~80°C) and low temperature (-6~18°C) were studied by Brinell rotary viscosity test, dynamic shear rheological test (including temperature scanning, frequency scanning, linear amplitude scanning) and bending beam rheological test. The test results show that both EC and M1 have good viscosity reduction effect on HVA at high temperature, and can effectively reduce the construction temperature. At medium temperature, M1 can effectively improve the fatigue resistance of HVA, and the fatigue life can be increased by about 30% when the dosage is 0.6%. EC can increase the rutting factor of HVA and improve its resistance to deformation, but it will reduce its fatigue performance. When the dosage is 4%, the fatigue life will be reduced by about 9%. At low temperature, M1 can reduce the creep stiffness S, increase the creep rate m, and improve the low temperature performance of HVA, while EC has the opposite effect, weakening the low temperature performance of HVA. The results are helpful to understand the rheological properties of warm mix HVA and promote its application.

Effect of genes on rheological properties of asphalt binders

The future studies of materials would inexorably be innovated by genome ideas. The concept of asphalt genes was introduced in this work to develop an understanding of the Structure-Activity relationship between asphalt genes and rheological behaviors. Firstly, virgin asphalt binders were prepared from six crude oils, and expanded the asphalt samples by ageing method. Then, thirty genes of asphalt were extracted using various chemical composition methods and the improved Brown-Ladner method. The rheological properties of asphalt were characterized by seven high-temperature and eight low-temperature parameters via systematic experiment investigation. Thirty genes of asphalt were translated into six principal components (ZG1, ZG2, ZG3, ZG4, ZG5, ZG6), and rheological parameters were also converted into two principal components in high-temperature (ZH1, ZH2) and two in low-temperature (ZL1, ZL2), respectively utilizing principal component analysis (PCA) method. Therefore, the Structure-Activity relationship between asphalt genes and rheological parameters was built. Subsequently, results demonstrated that both ZH1 and ZL1 can be reliably predicted through ZG parameters, achieving a goodness of fit exceeding 98% statistically. The findings provide insights into asphalt design and fabrication at the genetic dimension.

Multiscale characterization of the UV aging resistance and mechanism of light stabilizer-modified asphalt

Abstract To clarify the effect and mechanism of hindered amine light stabilizer (HALS) on the UV aging behavior of asphalt binder, T622-HALS was selected as the modifier for UV aging resistance of asphalt. The physicochemical properties and microstructure of T622 light stabilizer were comprehensively analyzed. The light stabilizer-modified asphalt was prepared and placed in the UV radiation chamber for UV aging treatment. Scanning electron microscope and atomic force microscope were used to analyze the microscopic morphology evolution of light stabilizer-modified asphalt induced by UV radiation. The thermal properties and functional group composition changes in light stabilizer-modified asphalt during UV aging were studied by using the thermogravimetric and infrared spectroscopy combined testing system. The decay laws of the physical and rheological performances of light stabilizer-modified asphalt were studied during UV aging process, and the effect of light stabilizer on the UV aging behavior of asphalt binder was clarified. The research results indicated that HALSs could alleviate the microcracks and roughness change on the surface of asphalt and reduce the content of functional groups such as carbonyl and sulfoxide in asphalt. Furthermore, HALS could reduce the value difference of physical and rheological properties of asphalt before and after UV aging, significantly improving the UV aging resistance of asphalt binder.

Thermal and mechanical properties of PEG4000 and PUSSPCMs for thermoregulation of asphalt

The purpose of this study is to assess the effect of polyurethane solid-solid phase change materials (PUSSPCMs) and polyethylene glycol (PEG4000) on the thermoregulatory and rheological properties of asphalt, as well as their potential for regulating asphalt pavement temperature. The chemical and thermodynamic characteristics of PEG4000 and PUSSPCMs were investigated using infrared spectroscopy (FTIR), adsorption test, polarized light microscopy (POM), X-ray diffractometer (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG), and atomic force microscopy (AFM). Meanwhile, the effects of PEG4000 and PUSSPCMs on asphalt road performance and micromorphology were determined by tests of thermoregulation, three major indexes, DSR segregation, and scanning electron microscopy (SEM). The results indicate that PUSSPCMs have no hydroxyl characteristic peaks of PEG4000 and isocyanate bonds after the complete reaction. PUSSPCMs exhibit better phase stability over PEG4000, the soft segment for thermal storage changes from crystalline to amorphous and is limited by the hard segment micro-region to maintain a stable solid phase. PUSSPCMs exhibit slightly weaker thermal storage properties than PEG4000, while the thermal stability and elastic modulus are stronger. PUSSPCMs-modified asphalt performs lower thermoregulation properties than PEG4000-modified asphalt, which improves with the increasing soft segments. Furthermore, the advantages of PUSSPCMs-modified asphalt are in terms of basic physical, rheological properties and storage stability. The micromorphology of PUSSPCMs-modified asphalt shows no visible cracks compared to PEG4000-modified asphalt and flattens with soft segment rises, which contributes to the thermoregulation and rheological properties of asphalt.

Changes in rheological and low-temperature characteristics of rubberized asphalt containing castor-based bio-oil under thermal-oxidative exposure

The proposed bio-modified rubberized asphalt (BMRA) technology integrates bio-oil and crumb rubber modifications, offering cost savings, waste reuse, improved asphalt performance, and reduced asphalt consumption. Like traditional asphalt, BMRA ages over time due to external environmental factors, impacting its pavement performance. This study examines the alterations in rheological and low-temperature characteristics of BMRA during thermal-oxidative aging. Results indicate that incorporating bio-oil minimizes alterations to the complex modulus and phase angle in aged asphalt. BMRA's crossover modulus significantly surpasses that of unaged rubberized asphalt (RA), showcasing the mitigating effect of bio-oil and crumb rubber on asphalt's rheological properties during aging. BMRA demonstrates comparable or enhanced peak load, fracture displacement, fracture toughness, and fracture energy relative to RA. BMRA's glass transition temperature remains lower than that of other unaged asphalts, signifying enhanced resistance to low-temperature cracking even after aging. Bio-oil, characterized by low molecular weight and abundant light components, counteracts performance deterioration attributed to volatile constituents and destabilization of asphalt's colloid structure during aging. Crumb rubber facilitates the absorption and subsequent release of specific light components, augmenting BMRA's resistance to aging. These findings enhance our understanding of the mechanisms governing the aging resistance and performance of bio-modified rubberized asphalt, thereby supporting the development of sustainable and durable asphalt materials.

Study on rheological properties of POE/VO compound recycled asphalt.

In order to improve the high temperature performance of Vegetable oil recycled asphalt, this study used Polyolefin elastomer (POE) and vegetable oil (VO) to compound recycled aging asphalt. The properties of recycled asphalt were compared and analyzed by conventional physical properties and high & low temperature rheological tests. The results show that 8% VO content can achieve the best regeneration effect. Based on this VO dosage, a variety of POE/VO combination mixture schemes were designed and tested to obtain excellent deformation resistance of recycled aging asphalt under high temperature environments. The POE/VO combination with an appropriate dosage can restore the high temperature deformation resistance and elastic recovery performance even beyond the pre-aging level, and increase the critical temperature by 4~10°C. Considering the physical properties and rheological properties of asphalt, the recommended ratio of POE/VO composite recycled asphalt is 8% VO+4% POE and 8% VO+6% POE.

CHARACTERIZATION OF ASPHALT MODIFICATION USING GROUND RUBBER AND REACTIVE RUBBER NR-g-MA AS COMPATIBILIZER

This study aims to improve the quality of asphalt by adding ground tyre rubber (GR) and reactive rubber (NR-g-MA) as compatibilizers of asphalt-rubber mixability. The use of GR has been widely used to improve the performance of asphalt and extend the service life of asphalt. The NR-g-MA used was the product of the copolymerization of SIR-20 rubber grafts with maleic anhydrous (MA) through a melting process in an internal mixer. Mixing of GR in asphalt was carried out in an external mixer with composition of asphalt/GR 95/5 phr at the temperature of 180oC for 90 minutes. The performance of asphalts were measured based on conventional test of penetration and softening point. The rheological properties of asphalt were measured using a Dynamic Shear Rheometer (DSR). Important parameters of the rheological properties measured are complex shear modulus (G*) and phase angle (d). Asphalt resistance to the permanent deformation (rutting) were determined on asphalt that has undergone a short-term aging process in a rolling thin film oven (RTFO) and measured at high temperatures (58-82OC). Fatigue crack resistance was tested on asphalt that has undergone a long-term aging process using the method of pressure aging vessel (PAV) and measured at low temperatures (25-31OC). Asphalt-GR mixtures' chemical, thermal and morphological properties were studied using ATR-FTIR, DSC/TGA, and SEM respectively. The results showed that adding used ground rubber (GR) decreased the penetration value by 9.93 – 18.87% and increased the softening point of asphalt from 5.57 – 11.40%. Rheological analysis showed that the addition of GR and compatibilizer NR-g-MA increase the value of complex shear modulus (G*) and decrease the phase angle (d) of the asphalt. The addition of ground rubber and reactive rubber of NR-g-MA to asphalt improve the performance of asphalt because it has rutting resistance at high temperatures as well as improves asphalt cracking resistance at low-temperature measurements. The addition of NR-g-MA reactive rubber to modified asphalt ground rubber can increase the mixability of asphalt-rubber used tires.

Reološka svojstva sintetiziranih aditiva u vrućoj asfaltnoj mješavini: stanje područja

In civil engineering, pavement, which is a mixture of aggregate and bitumen, is the layer most affected by traffic loads. Thus, problems, such as cracking, rutting, fatigue, aging, and moisture damage occur in the asphalt pavement layer throughout its service life. Such problems are generally caused by the increase in the number of heavily loaded vehicles, design and construction errors, and climate and environmental conditions. Scientists and engineers are continuously working on improving the performance of asphalt pavements. Particularly, recent studies have focused on improving multiple properties of asphalt simultaneously by chemically synthesising a novel material in the laboratory. This study aims to present a review of the effects of chemically synthesised additives on the performance of asphalt binders and mixtures. The findings of this study show that these new additives had a significant effect on the rheological properties of asphalt, such as rutting, elasticity, and fatigue life, when used in appropriate proportions. This study is expected to serve as a reference and guide for future studies on the production of new synthesised additives as asphalt modifiers.

Rheological Properties of Warm Mixed Asphalt

Adding a warm mixing agent to asphalt can lower the working temperature of asphalt construction by 20–40 °C. It is difficult to evaluate the impact of the existing warm mixed agent on the quality and effect of asphalt due to its wide variety. In this study, 70 # asphalt and 3 kinds of surfactants were selected to prepare warm mix asphalt. The result of different warm mix agents on the rheological properties of asphalt was evaluated through a rheological experiment. The results explained that the warm mixing agent could lower the Brookfield viscosity of asphalt. With the increase in asphalt temperature, the viscosity difference of different types of asphalt binder becomes smaller and smaller. A warm mixing agent will also reduce the creep stiffness of asphalt. In the multiple stress creep recovery test, the average recovery rate of asphalt and the average value of irrecoverable creep compliance have obvious stress dependence.

Effect of Multiple Aging-Rejuvenating Cycles (MARC) on critical rheological and fatigue properties of asphalt binder

A variety of recycling agents are widely applied today to restore and enhance the physical and rheological properties of reclaimed asphalt binders (RAB). Whereas the effectiveness of these recycling agents is significantly affected by their composition and the degree of aging of asphalt, it remains unclear if they are actually restoring the whole original binder properties, or only some of the critical properties. In addition, there remains important questions about repeated recycling and how much these agents can in fact continue to restore the critical performance-related properties of the repeatedly recycled binders. Therefore, multiple aging-rejuvenating cycles (MARC) test is specially designed and the changes of G*, phase angle, and fatigue properties of asphalt binders after repeated PAV aging and subsequent additions of selected recycling agents that vary significantly in composition are investigated. In this paper, the rheological properties of asphalt and the fatigue-LAS test are used to quantify the critical properties at different aging stages and recycling agents. Results show that while the recovery of G* is possible for all agents, it is more challenging to restore the phase angle by the recycling agents used. Furthermore, results demonstrate that the recycling agents have limited capacity for restoring fatigue life at high strain level after repeated aging. The findings raise concerns about the future of repeated recycling and highlight the need to evaluate more than the LVE properties, and to sort out the changes in phase angle from the G* in order to understand the effect of these recycling agents. Additionally, for recycling agents, the performance in each cycle will change in MARC. Compared with bio-oil, it is risky to directly utilize re-refined engine oil bottom (REOB) with aged asphalt because of its invalidation after MARC.

Modification of conditions and properties of dispersed reinforcing fiber during construction and operation of asphalt concrete pavements

Purpose: Identification of deformation presence or absence, fiber destruction in manufacturing asphalt concrete mixes contain ning polymer fiber.Methodology: Initial dispersed reinforcing fiber made of thermoplastic fiber-forming polymer and mineral thread, fiber extracted from asphalt concrete, and fiber exposed to weather conditions are investigated using a weatherometer IP-1-3. Аn MIM-10 metallographic microscope is used for the metallographic analysis. The infrared spectrophotometer SPECORD M-80 is used for the material identification. Physicochemical tests of fiber are carried out in a certified laboratory "Khimvolokno".Research findings: Dispersed reinforcing fiber made of thermoplastic fiber-forming polymers show deformation in compacting the asphalt-concrete mix at impact points of mineral material grains. At the same time, mineral fiber used as a dispersed reinforcement is not subjected to such deformation. The fiber properties are not affected by natural and climatic factors. It is found that natural and climatic factors do not cause the fiber destruction in dispersed reinforcement. The properties of reinforcing fiber slightly change, which allows them to perform a reinforcing function throughout the established service life of asphalt concrete pavements. Indentation of mineral material grains into fiber made of thermoplastic polymers leads to fiber jamming by grains, that prevents them from being pulled out, that, in turn, increases strength and rheological properties of asphalt concrete.Value: The analysis of chemical fiber characteristics is requireв to satisfy the growing interest in dispersed reinforcement of asphalt concrete. The quality of polymer fiber used for reinforcement can be changed under the influence of external factors and affect the quality of road pavements.

Experimental investigation of the interface interaction between asphalt binder and mineral filler from the aspects of materials properties

The strength of the interface between asphalt and filler is relatively low, making it susceptible to stress concentration and damage, which can affect the service life of the asphalt pavement. Current research indicates that there is a significant relationship between the interfacial interaction behavior and the properties of both asphalt and filler. Based on this, this study investigated the influence of both asphalt and filler properties on the interaction behavior of the asphalt-filler interface. Firstly, this study conducted research on existing interaction evaluation indicators and selected Palierne C as the optimal evaluation indicator for this study, which has the weakest correlation with filler volume fraction, in order to avoid the influence of filler volume fraction on experimental results. Secondly, this study analyzed the effects of asphalt SARA components and aging degree on the interface interaction ability between asphalt and fillers, as well as the rheological properties of asphalt. The research results found that the asphaltenes and resins fractions can enhance the interaction ability between asphalt and filler, as well as the high-temperature performance of asphalt. The content of these fractions was positively correlated with the interaction between the interfaces. In contrast, the content of aromatics and saturates fractions was negatively correlated with the interaction capacity. The strength of the interaction was negatively correlated with aging time, and long-term aging inhibited interface interaction to a greater extent than short-term aging. Finally, the mineral and chemical composition of common fillers were analyzed by X-ray diffraction (XRD) and X Ray Fluorescence (XRF). Subsequent studies were carried out on the interaction of the asphalt-filler interface in terms of the mineral composition, chemical composition, and particle size of the filler. It was found that in terms of mineral composition, albite and asphalt have the strongest ability to interact at the same temperature, followed by calcite and the weakest by quartz. In terms of chemical composition, the strongest interaction was between MgO and asphalt, followed by CaO, Fe2O3 and Al2O3, and the interaction between SiO2 and asphalt was the worst. In addition, the smaller the particle size of the filler, the greater the interaction capacity.

Evaluation of Biomass Solid Waste as Raw Material for Preparation of Asphalt Mixture

At present, the resource utilization of solid waste in China is facing prominent problems such as high production intensity, insufficient utilization, and low added value of products. The preparation of biomass composites from biomass solid waste and plastic solid waste reduces not only environmental pollution and energy consumption but also promotes the high-value utilization of solid waste. So, the characterization and preparation experiments of samples with two different biomass are carried out. The wheat straw fiber and corn straw fiber were added into the bio-asphalt mixture with the content of 0.1%, 0.2%, 0.3%, and 0.4%, respectively, with the content of 9% and 12% bio-heavy oil. The physical properties and rheological properties of asphalt were analyzed and evaluated by three indexes and a dynamic shear rheological test. Through the rutting test and immersion Marshall test, high-temperature performance and biological asphalt mixture’s water stability were evaluated. The results show that straw fiber can improve bio-asphalt mixture’s road performance, especially the performance of high-temperature rutting. When the fiber content of bio-asphalt with 9% bio-heavy oil content is 0.3%, the physical properties and rheological properties of bio-asphalt are the best. Corn straw fiber’s influence on bio-asphalt mixture was better than that of wheat straw fiber.

Surface Activation of Wax-Based Additives to Enhance Asphalt Rheological Properties via Rotating Plasma Treatment

Wax-based additives have been widely used in asphalt pavement for their preferable environmental benefits. However, poor compatibility between wax-based warm mix additives and asphalt easily leads to precipitation of wax and cracking of asphalt pavement. Plasma treatment can effectively modify the surface of various materials. This study applies plasma treatment to improve the surface properties of wax-based additives for compatibility improvement in asphalt binder. Compatibility of two different wax-base additives in asphalt binder before and after surface treatment is investigated via cigar tube test and morphology test. In parallel, rheological properties of wax-modified asphalt are characterized from the perspectives of rotational viscosity, rutting resistance, and fatigue performance. Results show the enhanced surface roughness and chemical activity of wax-based additives after plasma treatment. The adhesion between waxes and the asphalt matrix is significantly improved. Waxes within binder are uniformly dispersed after plasma treatment. The incorporation of surface activated wax helps to promote the viscosity reduction of asphalt binder. Furthermore, the high-temperature performance of wax-based asphalt after surface activation treatment of wax is significantly improved, especially for fatty acid amide waxes. As for fatigue performance, plasma treatment improves the fatigue resistance from a compatibility perspective. Therefore, plasma has great promise for facilitating wax-modified asphalt properties from a compatibility perspective.

Multiscale Evaluation of Asphalt Aging Behaviour: A Review

The performance of asphalt pavement will deteriorate gradually due to oxidation, also named the ageing of asphalt binders. In this study, the research progress on the multiscale evaluation of asphalt aging behaviour in the past decade was reviewed to further analyse the evolution law of asphalt aging behaviour and determine the asphalt aging mechanism. Firstly, artificial aging methods were introduced, the factors affecting asphalt aging behaviour were analysed, and the changes of asphalt properties before and after aging were identified. Secondly, the methods and research progress in terms of the evaluation of asphalt aging degrees were summarised from the macro-, mesoscopic-, micro-, and nanoscales. Finally, considering extensively studied rheological properties as an example, the correlations among the rheological properties of asphalt in the aging process and the conventional physical properties, chemical composition, microscopic properties, nano-molecular dynamics, and other parameters were analysed. The results show that various scales are interrelated, and the multiscale evaluation of asphalt aging can provide a more comprehensive prediction of the extent of asphalt aging. The correlation between multiple scales enables a thorough analysis of the mechanism of asphalt aging and the evaluation of asphalt aging behaviour at multiple scales.

Modification effects of multi-walled carbon nanotubes on the mechanical and rheological properties of epoxy asphalt

Epoxy asphalt (EA) was widely used in road engineering fields, but previous research found that there were compatibility problems between epoxy (EP) and asphalt. In practical engineering applications, the compatibility of EA was improved by adding complex auxiliary agents. Although the composite of multi-walled carbon nanotubes (MWCNTs) and epoxy could improve the adhesion, corrosion resistance, and toughness of asphalt, it was difficult to achieve an excellent modification effect because of the agglomeration of MWCNTs. To improve the composite effect of epoxy and MWCNTs, carboxyl functional groups were added to MWCNTs under mixed acid conditions to reduce the agglomeration and achieve a better combination with epoxy. Then, MWCNTs/EP was prepared under physical stirring conditions. The MWCNTs/EP was observed by scanning electron microscopy (SEM), and it was found that MWCNTs could be uniformly dispersed in epoxy. To research the modification effect of MWCNTs on mechanical and rheological properties of EA, a variety of MWCNTs/EA with different proportions were prepared. The impact of different mixing ratios of MWCNTs/EP on the mechanical and rheological properties of asphalt was evaluated by dynamic shear rheological (DSR) experiments. The results showed that the addition of the appropriate amount of MWCNTs could further improve the high-temperature stability of EA. In this case, MWCNTs played a positive role in the modification of epoxy. However, the improper introduction of MWCNTs would have a negative weakening effect, which would weaken the high-temperature performance of EA. Through comparison, the optimal mixing ratios of MWCNTs and epoxy were finally determined as 6 % EP + 1.4 % MWCNTs and 20 % EP + 0.125 % MWCNTs.

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 of Anti-Stripping Measures to Improve the Adhesion of Asphalt to Granite Aggregates

Granite is very widely distributed in the world, but granite is an acidic aggregate with poor adhesion to asphalt. In untreated asphalt mixtures, asphalt pavement water damage and loose disease are more prominent, affecting the service life of the pavement and service level. Enhancing the road performance of granite asphalt mixture generally improves the adhesion properties of asphalt and granite. Qingchuan rock asphalt, anti-stripping agent KH5, aliphatic amine anti-stripping agent AJ-1 and two groups of the composite anti-stripping agents were used to modify the asphalt and analyze the effect of different anti-stripping agents on the improvement of asphalt-granite aggregate adhesion properties based on the surface free energy (SFE) theory. Second, the effect of anti-stripping agents on the rheological properties of asphalt were analyzed by rheological tests, and the modification effect of granite asphalt mixture road performance was evaluated by Marshall tests. The aging of asphalt and asphalt mixture was simulated by thermal oxygen aging, and the durability of different anti-stripping agents was investigated by comparing the performance of asphalt and asphalt mixtures before and after aging. The results showed that Qingchuan rock asphalt can effectively enhance the high-temperature stability and anti-aging properties of asphalt mixes, but the low temperature performance was relatively poor. KH5 and AJ-1 can make up for the lack of low temperature performance of rock asphalt, but the water stability of asphalt mixes decreases after aging. All five groups of anti-stripping agents improve the adhesion of granite-asphalt and the water stability of the asphalt mixture to some extent. Considering the aging effect, the order of granite-asphalt mixture water stability is: KH/RAMA > AJ/RAMA > RAMA > KHMA > AJMA.