Composite Modified Asphalt Mixture Research Articles

Assessing pavement characteristics: An in-depth evaluation of waste engine oil and Buton rock asphalt composite modified asphalt and its mixture

To investigate the cooperative influence of waste engine oil (WEO) and Buton rock asphalt (BRA) on asphalt characteristics, the WEO/BRA composite modified asphalt and its mixture with varied dosages were prepared. The high-, moderate-, and low-temperature assessments of WEO/BRA composite modified asphalt were conducted through temperature sweep tests, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The softening point difference was used to analyze the storage stability of composite modified asphalt. Based on the Fourier transform infrared spectroscopy (FTIR) and fluorescence microscope (FM) test, the microscopic feature and chemical constitution of WEO/BRA composite modified asphalt were analyzed. Rutting test, low-temperature bending test, immersed Marshall test, freeze-thaw splitting test, and four-point fatigue bending test were carried out to verify the pavement properties of the WEO/BRA composite modified asphalt mixture. The results indicated that WEO improved the capability in low-temperature conditions and fatigue properties of asphalt modified with BRA. BRA enhanced the high-temperature property of asphalt modified with WEO. The synergistic effect of WEO, BRA, and neat asphalt was a physical reaction, and these modifiers were uniformly distributed in the asphalt. Meanwhile, WEO/BRA composite modified asphalt had excellent storage stability for the single modified asphalt. The test results of the asphalt mixture verified the results, indicating that WEO/BRA composite modified asphalt can be considered a new green and durable asphalt pavement material.

The Multi-Objective Optimization Design and Hydrothermal Performance Evaluation of Anhydrous Calcium Sulfate Whisker and Polyester Fiber Compound Modified Asphalt Mixture in Hot-Humid Areas.

In hot and humid climates, asphalt pavements frequently encounter environmental factors such as elevated temperatures and rainfall, leading to rutting deformations and potholes, which can affect pavement performance. The primary objective of this study was to enhance the hydrothermal characteristics of asphalt mixtures through an investigation into the impact of anhydrous calcium sulfate whisker (ACSW) and polyester fiber (PF) on the hydrothermal properties of asphalt mixtures. In this paper, a central composite concatenation design (CCC) was employed to determine the optimal combination of ACSW and PF contents, as well as the asphalt aggregate ratio (AAR). Each influencing factor was assigned three levels for analysis. The evaluation indexes included dynamic stability, retained Marshall stability, and tensile strength ratio. Using the analysis methods of variance and gray correlation degree analysis, the hydrothermal properties of the asphalt mixture were examined in relation to the contents of ACSW, PF, and AAR based on the CCC results. Consequently, the optimal mix design parameters for composite modified asphalt mixture incorporating ACSW and PF were determined. The results indicated that the asphalt mixtures with hydrothermal qualities exhibited optimal performance in terms of 4.1% ARR, 11.84% ACSW, and 0.4% PF. The interaction between AAR and ACSW content had a greater effect on the dynamic stability and tensile strength ratio of the asphalt mixture, whereas the incorporation of ACSW and PF had a greater effect on the retained Marshall stability of the asphalt mixture. Among the three contributing factors, AAR exhibited the strongest relationship with the hydrothermal characteristics of the asphalt mixture, followed by the ACSW content; the correlation of PF content was the lowest. Therefore, to enhance the hydrothermal characteristics of the asphalt mixture, it is important to conduct a full evaluation of the constituents of ACSW and PF, along with the AAR in hot-humid regions.

Research on Fatigue-Healing Performance of Asphalt Mixture Based on the Semicircular Bending Test.

In order to study the self-healing performance of macroscopic fractures of asphalt mixtures, semicircular bending (SCB) tests were used to test 90# base asphalt mixtures, SBS (Styrene-Butadiene-Styrene) modified asphalt mixtures, and SBS + CR (Chloroprene Rubber) composite modified asphalt mixtures. The F-H-F (the asphalt mixture specimen was fatigued for a certain number of times, then healed under certain conditions, and then fatigued until destroyed) test was carried out, and the fatigue life recovery rate of the fatigue test before and after healing was defined as the healing index (HI). The gray correlation analysis method was used to judge the influence degree of influencing factors on fatigue-healing according to the correlation index. The results show the type of asphalt has the most significant influence on the healing ability of the asphalt mixture. In the case of complete healing, the fatigue-healing performance of the SBS + CR composite modified asphalt mixture was the best, followed by the SBS-modified asphalt mixture, and 90# base asphalt. When the healing temperature is close to the softening point of asphalt, the healing performance of 90# base asphalt is better when the healing temperature is low. When the healing time is longer, the healing performance is better, and there is an optimal healing time. The healing index decreased with the increase in the degree of damage. When the degree of damage is too large, the asphalt mixture will be difficult to heal.

Evaluation of Low-Temperature Performance of SBS/CR Composite Modified-Asphalt Mixture under Aging and Freeze–Thaw Cycles

Evaluation of Low-Temperature Performance of SBS/CR Composite Modified-Asphalt Mixture under Aging and Freeze–Thaw Cycles

Performance of Dry Mixed Rubber–Plastic Composite Modified Asphalt Mixture

Performance of Dry Mixed Rubber–Plastic Composite Modified Asphalt Mixture

Fatigue characteristics and environmental sustainability of rubber asphalt composite modified asphalt mixtures incorporating nanosilica

Nano materials such as nanosilica have recently been used to modify the properties of rubberized asphalt mixtures. Depite the performance improvement of the modified mixtures, there are still concerns about nanosilica's pathways contributing to environmental problems. In light of these concerns, this research was conducted to evaluate the fatigue charcateristics and environmental sustainability of rubber asphalt composite modified mixtures incorporating nanosilica using the life cycle assessment (LCA) methodology. The fatigue performance prediction was determined by means of numerical simulation implemented in finite element (FE) dynamic implicit Abaqus code. The LCA was carried out in accordance with ISO 14,040 standards and implemented in SimaPro 9.2.1 LCA commercial software. The FE model results showed that asphalt pavement with rubber asphalt/nanosilica composite modified asphalt mixture (herein composite mixture) had lower tensile strains at the bottom of asphalt layer as compared to the pavements with conventional rubberized asphalt mixtures (herein conventional mixture). This increased the fatigue life of the composite mixtures. The LCA results revealed that the composite mixtures had a global warming potential (GWP) of 5.92 x104 kg CO2-Eq compared to 6.56 × 104 kg CO2-Eq per functional unit for the conventional mixtures. Despite the reduction in GWP, composite mixture had a negative effect on the acidification potential of the impact category. Based on the research findings, the study concluded that nanosilica can evidently reduce global warming potential of rubberized asphalt mixtures but further research is needed to address the acidification potential of nanosilica before industrial-scale utilization of nanosilica additive in pavement construction.

Performance and inorganic fume emission reduction of desulfurized rubber powder/styrene–butadiene–styrene composite modified asphalt and its mixture

Rubber asphalt (RA) and styrene–butadiene–styrene (SBS) modified asphalt are widely used for all roads grades. However, the fumes generated by RA preparation as well as the high cost of SBS modified asphalt have limited their widely development. To address these challenges, desulfurized rubber powder (DRP) was developed as a cheap and clean modifier. Herein, DRP and SBS were applied to produce composite modified asphalt. Afterward, experiments were performed to evaluate the performances of the resulting blend. The basic physical properties of the DRP/SBS composite modified asphalt were satisfactory when DRP and SBS comprised 15% and 4% of the blend, respectively. Regarding the road performances, the DRP/SBS composite modified asphalt mixture performed much better than SBS modified asphalt mixture. Moreover, microcosmic property tests and inorganic fume emission monitoring indicated that the DRP/SBS composite modified asphalt reduced fumes because of the stable chemical bonding of DRP, absorption of the light components, and increased swelling. Finally, the DRP/SBS composite modified asphalt and its mixture significantly reduced SO2 emissions by more than 40% and NO2 and NOx emissions by more than 50%, which demonstrated their potentially significant contributions toward field construction application and environmental protection.

Effect of Freeze–Thaw cycles on the pavement performance of SBS modified and composite crumb rubber modified asphalt mixtures

The effect of freeze–thaw cycles on the pavement performance of SBS modified asphalt mixture (SBSMA) and SBS/crumb rubber composite modified asphalt mixture (CCRMA) was studied using a triaxial repeated creep test, semicircular bending fatigue test based on digital image correlation (DIC), and thermal stress restrained specimen test. The mechanical model of the residual strain (RS) of the asphalt mixtures is established, and the residual viscous flow strain (εRvf,N) and residual viscoelastic strain (εRve,N) are separated. Based on the horizontal strain (Exx) of DIC, a new mesofatigue damage variable (D) is proposed. According to the characteristic curve of D, the antifatigue damage parameter (AFDP) is established and the correlation between AFDP and fatigue life (Nf) is analyzed. Simultaneously, a calculation model of the relaxation temperature stress (σRts(T)) of the asphalt mixture at different cooling rates (v) is established based on the finite element method. Results showed that the growth rates of RS, εRvf,N, and D of both asphalt mixtures accelerate, AFDP decreases, and freeze–break temperature (TD) rises with increasing freeze–thaw cycles. However, the growth rates of RS, εRvf,N, and D of CCRMA are always slower than SBSMA, the AFDP is larger than SBSMA, TD is lower than SBSMA, εRve,N is a fixed value under specific conditions, and a good correlation exists between the AFDP and Nf. The pavement performance of the asphalt mixtures worsens after the freeze–thaw cycles, and the influence of a salt freeze–thaw cycles is greater than that of a water freeze–thaw cycles. Moreover, CCRMA has better high-temperature deformation resistance, fatigue damage resistance, and low-temperature cracking resistance than SBSMA. The conversion point temperature (TZ) increases with the acceleration of v, and the σRts(T) calculation model can accurately reflect the σRts(T) of the asphalt mixture at different v.

Durability Capacity Change of Rubber Powder Composite BRA Modified Asphalt Mixture

Both engineering practice and literature confirm that the high modulus asphalt mixture has superior performance. If modified, the final asphalt mixture can effectively improve the service life of asphalt pavement. Therefore, the design and test of this paper are trying to mix rubber powder and BRA to prepare high modulus Sup-13 asphalt mixture. Through a series of experimental studies, this paper discusses the effect of adding rubber powder and BRA separately and the effect of adding both rubber powder and BRA into asphalt mixture on its durability. The experimental part mainly focuses on the composite modified asphalt mixture water resistance test, the high temperature stability test, and the low temperature crack resistance test, and it is concluded that the rubber powder and the BRA compound modification can equalize the improvement effect of strength, modulus, and strain. For this reason, if the rubber powder with finer particle size is adopted to modify the asphalt mixture, the low temperature crack resistance of the specimen will improve apparently.

Investigation on Fatigue Performance of Diatomite/Basalt Fiber Composite Modified Asphalt Mixture.

The fatigue resistance of asphalt mixture is an important indicator to evaluate the durability of asphalt pavement. In order to improve the fatigue properties of asphalt mixture, diatomite and environmental basalt fiber were added. Four types of asphalt mixtures, ordinary asphalt mixture (AM), diatomite modified asphalt mixture (DAM), basalt fiber modified asphalt mixture (BFAM) and diatomite/basalt fiber composite modified asphalt mixture (DBFAM), were chosen, whose optimum asphalt–aggregate ratio, optimum content of diatomite and optimum content of basalt fiber could be determined by Marshall test and response surface methodology (RSM). The multi-functional pneumatic servo Cooper test machine was carried out by a four-point bending fatigue test. Through the comparative analysis of flexural-tensile stiffness modulus (S), initial stiffness modulus(S0), residual stiffness modulus ratio, lag angle (ϕ) and cumulative dissipation energy (ECD), the fatigue resistance of asphalt mixture can be effectively improved by adding diatomite and basalt fiber. Grey correlation analysis was also used to analyze the degree of correlation between the fatigue life and the influencing factors such as VV, VMA, VFA, OAC, S, and ECD. The analysis results indicate that ECD has the greatest impact on the fatigue life of the asphalt mixture.

Research on the Fatigue Life Prediction for a New Modified Asphalt Mixture of a Support Vector Machine Based on Particle Swarm Optimization

SMC (Styreneic Methyl Copolymers) is a novel normal temperature asphalt modifier with superior performance. It has the advantages of a low construction temperature, good road performance, good energy savings and an emission reduction effect, and can improve the performance of an asphalt mixture. The fatigue performance of an asphalt mixture is one of the important technical parameters in the structural design of asphalt pavements. The fatigue performance of an asphalt mixture under specific traffic and environmental conditions has an important guiding significance and normative function for the design, construction, and maintenance of asphalt pavement. In this paper, the mixture of an SMC normal-temperature-modified asphalt and styrene–butadiene styrene block copolymer (SBS)-modified asphalt (SMCSBS) compound-modified asphalt was investigated, and an SMCSBS composite modified asphalt mixture with a different SMC content was prepared. A semi-circular bending fatigue test (SCB) was conducted to analyze and compare the fatigue properties of the modified asphalt mixture. On this basis, this paper proposes a fatigue life prediction model of an SMCSBS composite modified asphalt mixture based on a particle swarm optimization support vector machine (PSO-SVM). SMC content (SMC accounts for the mass percentage of SMCSBS composite modified asphalt)/%, asphalt aggregate ratio, stress ratio and loading frequency/Hz were used as training data to establish the prediction model, and RMSE and R2 were used to evaluate the performance of the model. Experimental results show that the prediction results of the PSO-SVM method are more accurate than the experimental observation data and can effectively improve the prediction accuracy of the model. Compared with the M5′ model tree (M5′), artificial neural network (ANN), and support vector machine (SVM) method, the PSO-SVM method can achieve better prediction performance and a better prediction effect.

Laboratory Investigation of Carbon Black/Bio-Oil Composite Modified Asphalt.

As environmentally friendly materials, carbon black and bio-oil can be used as modifiers to effectively enhance the poor high-temperature and low-temperature performance of base asphalt and its mixture. Different carbon black and bio-oil contents and shear time were selected as the test influencing factors in this work. Based on the Box–Behnken design (BBD), carbon black/bio-oil composite modified asphalt was prepared to perform the softening point, penetration, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The response surface method (RSM) was used to analyze the test results. In addition, the base asphalt mixtures and the optimal performance carbon black/bio-oil composite modified asphalt mixtures were formed for rutting and low-temperature splitting tests. The results show that incorporating carbon black can enhance the asphalt’s high-temperature performance by the test results of irrecoverable creep compliance (Jnr) and strain recovery rate (R). By contrast, the stiffness modulus (S) and creep rate (M) test results show that bio-oil can enhance the asphalt’s low-temperature performance. The quadratic function models between the performance indicators of carbon black/bio-oil composite modified asphalt and the test influencing factors were established based on the RSM. The optimal performance modified asphalt mixture’s carbon black and bio-oil content was 15.05% and 9.631%, and the shear time was 62.667 min. It was revealed that the high-temperature stability and low-temperature crack resistance of the carbon black/bio-oil composite modified asphalt mixture were better than that of the base asphalt mixture because of its higher dynamic stability (DS) and toughness. Therefore, carbon black/bio-oil composite modified asphalt mixture can be used as a new type of choice for road construction materials, which is in line with green development.

Investigation on the piezoresistive response of carbon fiber-graphite modified asphalt mixtures

The correlation between the electrical properties of carbon fiber-graphite composite conductive asphalt mixes and their cracking damage can provide an early warning function for cracking. This study is devoted to exploring the force-electrical sensitivity of conductive concrete to find new solutions for asphalt pavement cracking warning. Firstly, a carbon fiber-graphite composite modified asphalt mixture was prepared; Secondly, the force-electrical sensitivity of the mixture was verified by direct and indirect tensile creep test. The tests showed that the resistivity and its cracking degree had a strong correlation. As the crack increases, so does the resistance. When the cracking reaches a certain level, the sudden change in resistance indicates that the mixture has been destroyed internally. Its resistivity and strain show a clear correlation before the mixture is broken. With the increase of strain, the resistivity gradually decreases. At the stage of large fluctuations in resistivity, it can be assumed that the mixture has reached the load carrying capacity limit, and at the stage of increasing resistivity abruptly, it can be judged that the mixture has undergone damaged and lost strength. Finally, the road performance was verified. A comparative study found that the high temperature, water stability and crack resistance are better than those of ordinary and graphite, and the fatigue performance is better than that of graphite. The research of the carbon fiber-graphite composite conductive asphalt concrete provides technical support for the application of the next crack warning function.

Study on Properties of Bone Glue/Polyurethane Composite Modified Asphalt and Its Mixture

Composite modification technology is widely used in the materials field. To enhance the property of polyurethane modified asphalt and realize its application in road engineering, the bone glue/polyurethane composite modified asphalt (CMA) was prepared using bone glue, polyurethane, and neat asphalt in this research. The bone glue content ranges 5–10%, that of the polyurethane is 1–5%. The relationship between the modifier’s content and the conventional properties and rheological properties of CMA was revealed by response surface methodology (RSM). The CMA performance was further verified under the optimal content of the bone glue and polyurethane. The differences of properties of styrene–butadienestyrene (SBS) modified asphalt mixture, neat asphalt mixture, and bone glue/polyurethane CMA mixture were compared and analyzed by using the pavement performance test. The results showed that the CMA’s conventional properties and rheological properties are improved. The optimal bone glue content and polyurethane content determined by RSM are 6.848% and 2.759%, respectively. The low-temperature crack resistance and water stability of the CMA mixture are enhanced, better than neat asphalt mixture and SBS modified asphalt mixture. The CMA mixture’s dynamic stability is 85% of SBS modified asphalt mixture, but it is 2.4 times of neat asphalt mixture. The result indicated that the bone glue/polyurethane CMA mixture still has certain advantages of high-temperature stability. In this research, the composite modification of bone glue and polyurethane can significantly enhance the characteristic of asphalt and asphalt mixture and provide a new method for applying and promoting polyurethane modified asphalt in road engineering.

Machine Learning Approach to Develop a Novel Multi-Objective Optimization Method for Pavement Material Proportion

Asphalt mixture proportion design is one of the most important steps in asphalt pavement design and application. This study proposes a novel multi-objective particle swarm optimization (MOPSO) algorithm employing the Gaussian process regression (GPR)-based machine learning (ML) method for multi-variable, multi-level optimization problems with multiple constraints. First, the GPR-based ML method is proposed to model the objective and constraint functions without the explicit relationships between variables and objectives. In the optimization step, the metaheuristic algorithm based on adaptive weight multi-objective particle swarm optimization (AWMOPSO) is used to achieve the global optimal solution, which is very efficient for the objectives and constraints without mathematical relationships. The results showed that the optimal GPR model could describe the relationship between variables and objectives well in terms of root-mean-square error (RMSE) and R2. After the optimization by the proposed GPR-AWMOPSO algorithm, the comprehensive pavement performances were enhanced in terms of the permanent deformation resistance at high temperature, crack resistance at low temperature as well as moisture stability. Therefore, the proposed GPR-AWMOPSO algorithm is the best option and efficient for maximizing the performances of composite modified asphalt mixture. The GPR-AWMOPSO algorithm has advantages of less computational time and fewer samples, higher accuracy, etc. over traditional laboratory-based experimental methods, which can serve as guidance for the proportion optimization design of asphalt pavement.

Rhysiological properties of graphene nanoplatelets/rubber crowd composite modified asphalt

The purpose is to enhance the service life of heavy cross asphalt pavement and maintain good road performance throughout the service cycle. Graphene nanoplatelets/rubber crowd composite modified asphalt were prepared. The influence of different temperature and frequency on the high temperature performance of composite modified asphalt was evaluated. The viscoelastic energy of composite modified asphalt under different stress and different temperature was assessed. The rheological properties of GNPs/rubber powder composite modified asphalt at low temperature were studied. The microstructure and ir spectra of composite modified asphalt were compared and analyzed. The results show that the high and low temperature properties and viscoelasticity of rubber powder modified asphalt can be improved by adding GNPs. GNPs/rubber powder composite modified asphalt can effectively improve the performance of asphalt pavement in high temperature and heavy load traffic. The combination of GNPs and rubber powder improves the crack resistance of asphalt at low temperature. By analyzing the microscopic mechanism, it can be seen that GNPs has optimized the segregation phenomenon of rubber powder modified asphalt and improved the adhesion between asphalt and ore in the composite modified asphalt mixture.

Optimization Design of the Mix Ratio of a Nano-TiO2/CaCO3-Basalt Fiber Composite Modified Asphalt Mixture Based on Response Surface Methodology

This research optimizes the mix ratio of nano-TiO2/CaCO3 (NTC)-basalt fiber (BF) composite modified asphalt mixture. Based on the Box–Behnken method and the response surface method, a three-factor and three-level test was designed. The input indicators were the asphalt–aggregate ratio, NTC content, and BF content. The output indicators were the density, air voids, Marshall stability, flow value, voids in mineral aggregate (VMA), and voids filled with asphalt (VFA) values of the asphalt mixture. The response surface model was established according to the test response index value. Then, the function was fitted through multiple regression equations and multivariate analysis of variance was performed. Finally, according to the specification requirements and engineering needs, the selected conditions of each response value were determined to optimize the asphalt–aggregate ratio and the contents of NTC and BF, and the predicted values were verified through the measured data. The test results show that the optimal contents of NTC and BF and the optimal asphalt–aggregate ratio were 5.1%, 3.9%, and 5.67%, respectively. By comparing the measured Marshall test index value with the predicted value, the minimum relative error was 0.096% and the maximum error was 6.960%. The results show that response surface methodology can be used to optimize the mix ratio of composite modified asphalt mixtures.

Comparative analysis of mechanical behavior of composite modified asphalt mixture based on PG technology

Each different kind of asphalt has its own PG classification, and different temperature classifications of asphalt can be applied to different regions. However, the commonly used 90# asphalt and SBS modified 90# asphalt do not meet the temperature difference requirements of different regions. In order to study the asphalt mixtures that are used in regions with different temperatures, this project uses styrene–butadienestyrene (SBS), styrene butadiene rubber (SBR), rubber powder, and thermo plastic styrene (TPS) with a composite modification of 90# asphalt and 110# asphalt. This study compares the road performance of the different composite modified asphalt mixture. The optimum amount of modifier for the composite modified asphalt specimens was obtained by means of an asphalt penetration test, a ductility test, a softening point test, and a viscosity test. The results show that the high and low temperature performance of the composite modified asphalt specimen is better than that of the single modified asphalt specimen. In terms of the comparison between 90# asphalt and 110# asphalt, 110# asphalt has better low temperature performance, while 90# asphalt has better high temperature performance; the water stability is not significantly different. Among the six composite modified asphalt mixtures that were tested, the SBS/rubber composite modified 110# asphalt mixture has the best road performance, especially with respect to high temperature performance. This paper provides some advice about asphalt materials selected from different regions based on PG technology。The research results have theoretical and practical value for improving the mechanical performance of asphalt pavement in different regions.

Application of Waste Rubber Powder/SBS Double Compound Modified Asphalt in Xining South Beltway

Through the application of waste rubber powder/SBS double composite modified asphalt in Xining South Beltway, its superior road performance and construction feasibility have been verified. The road test results show that: The rutting stability of waste rubber powder/SBS double composite modified asphalt mixture reached 7800 times/mm, far exceeding the requirement of more than 3000 times/mm. The water stability and low-temperature bending performance also met the requirements of the index.

Comparative study on durability of different composite modified asphalt mixtures

The durability of asphalt mixture is one of the main indicators of the mechanical performance of asphalt pavement. Three kinds of composite modified asphalts (4%SBS/3%SBR, 4%SBS/15% rubber powder and 4%SBR/15% rubber powder) were chosen as binders. Three kinds of aggregate gradation (AC-13, AC-16, AC-20) were used to design composite modified asphalt mixture. The durability (ageing, accumulation and fatigue) of composite modified asphalt mixture was compared and analysed. The study includes comparative study on mechanical performance of composite modified asphalt with different ageing time (0, 5 and 20 h), comparative study on plastic deformation accumulation of composite modified asphalt mixture with different loading times and comparative study on fatigue characteristics of different composite modified asphalt mixtures based on strain. The findings have some theoretical and practical values for increasing the durability of asphalt pavement.