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The traditional method for determining mixing and compaction temperatures of asphalt binders, such as Brookfield viscosity test, often yields excessively high temperatures when used in many modified asphalts, and underestimates the temperature decreasing effect of the additives when used in warm-mixing asphalts. This study proposed a new viscosity measurement method, namely rotational plate viscosity (RPV) testing, to overcome these issues. The new method uses a Dynamic Shear Rheometer (DSR) with a 25-mm-diameter parallel plate geometry and a fixed shear rate 40 s−1 to measure the viscosity-temperature curve of modified asphalts, which minimizes the effect of the shear-thinning behavior. In addition, there are two main advantages of this new method. First, it can be carried out using an existing standard DSR machine typically used in most asphalt binder laboratories. Second, it can greatly improve the accuracy and efficiency of testing with sophisticated sensors and programmed settings.
Haoyuan Luo; XiaoMing Huang; Tian Rongyan; Haibo Ding; Jinhui Huang; Dalin Wang; Yuhao Liu; Zhengqiang Hong. Advanced method for measuring asphalt viscosity: Rotational plate viscosity method and its application to asphalt construction temperature prediction. Construction and Building Materials 2021, 301, 124129 .
AMA StyleHaoyuan Luo, XiaoMing Huang, Tian Rongyan, Haibo Ding, Jinhui Huang, Dalin Wang, Yuhao Liu, Zhengqiang Hong. Advanced method for measuring asphalt viscosity: Rotational plate viscosity method and its application to asphalt construction temperature prediction. Construction and Building Materials. 2021; 301 ():124129.
Chicago/Turabian StyleHaoyuan Luo; XiaoMing Huang; Tian Rongyan; Haibo Ding; Jinhui Huang; Dalin Wang; Yuhao Liu; Zhengqiang Hong. 2021. "Advanced method for measuring asphalt viscosity: Rotational plate viscosity method and its application to asphalt construction temperature prediction." Construction and Building Materials 301, no. : 124129.
In this study, the underlying causes of the performance degradation of three typical waste-oil-rejuvenated asphalts (i.e., asphalts rejuvenated by waste cooking oil (WCO), waste bio-oil (WBO), and waste engine oil (WEO)) after secondary aging are explored via SARA fractions analysis. The rejuvenation provided by WCO is found to be mainly based on supplementing aged asphalt with saturates, which causes the newly formed colloids to easily lose light components and exhibit low stability. Further, WEO contains some metal residues that catalyze the oxidation and polycondensation process of asphalt. Consequently, the performance of the asphalts rejuvenated separately by WCO and WEO is severely degraded during aging. By contrast, WBO has a stable colloidal structure and lacks ashes; thus, WBO-rejuvenated asphalt exhibits the most stable and reasonable performance degradation in the aging process. Our research suggests that the effect of rejuvenation on aged asphalt cannot be judged only by the difference between the performances of the rejuvenated asphalt and the original asphalt. The performance maintenance of the rejuvenated asphalt during the secondary aging process requires further investigation.
Haoyuan Luo; XiaoMing Huang; Rongyan Tian; Jinhui Huang; Binshuang Zheng; Dalin Wang; Bangyi Liu. Analysis of relationship between component changes and performance degradation of Waste-Oil-Rejuvenated asphalt. Construction and Building Materials 2021, 297, 123777 .
AMA StyleHaoyuan Luo, XiaoMing Huang, Rongyan Tian, Jinhui Huang, Binshuang Zheng, Dalin Wang, Bangyi Liu. Analysis of relationship between component changes and performance degradation of Waste-Oil-Rejuvenated asphalt. Construction and Building Materials. 2021; 297 ():123777.
Chicago/Turabian StyleHaoyuan Luo; XiaoMing Huang; Rongyan Tian; Jinhui Huang; Binshuang Zheng; Dalin Wang; Bangyi Liu. 2021. "Analysis of relationship between component changes and performance degradation of Waste-Oil-Rejuvenated asphalt." Construction and Building Materials 297, no. : 123777.
As an additive to improve the performance of asphalt binder, tire pyrolysis carbon black is gradually being used in road engineering, but the effect of carbon black (CB) with different particle sizes on asphalt modification remains to be further studied. In this study, three kinds of particle sizes and three kinds of contents of CB were used to modify asphalt, and different tests were conducted to research the high temperature performance and fatigue resistance of carbon black modified asphalt binder. It is found that the addition of CB can enhance the rutting resistance and medium temperature fatigue performance of virgin asphalt binder in general. However, for CB of 270 μm and 2.6 μm, its addition under certain contents lead to the decrease of high temperature performance and fatigue performance of the asphalt binder. For aged asphalt, the addition of CB decreases the rutting resistance and improves the fatigue resistance. The recommended content and particle size of CB are 2% and 2.6 μm. This study refines the complex effects of CB on asphalt properties, providing a reference for determining the size and content of CB in asphalt modification.
Kunzhi Zhong; Zhi Li; Jianwei Fan; Guangji Xu; XiaoMing Huang. Effect of Carbon Black on Rutting and Fatigue Performance of Asphalt. Materials 2021, 14, 2383 .
AMA StyleKunzhi Zhong, Zhi Li, Jianwei Fan, Guangji Xu, XiaoMing Huang. Effect of Carbon Black on Rutting and Fatigue Performance of Asphalt. Materials. 2021; 14 (9):2383.
Chicago/Turabian StyleKunzhi Zhong; Zhi Li; Jianwei Fan; Guangji Xu; XiaoMing Huang. 2021. "Effect of Carbon Black on Rutting and Fatigue Performance of Asphalt." Materials 14, no. 9: 2383.
To fully consider the impact of asphalt pavement rut on steering stability of autonomous vehicles, the sensitivity of various indicators of rut shape to vehicle stability was comprehensively measured, and pavement rut control standards based on comfort demands of autonomous vehicles were investigated. Firstly, a steering control system for autonomous vehicles was built in Simulink according to fuzzy control theory. Then, through orthogonal experiment design theory, different rut shape indicators are simulated in CarSim. The influence sensitivity of different rut shape indicators and the allowable rut range considering driving comfort were studied. The results show that both the rut depth and the rut side angle have a greater effect on the vehicle vertical acceleration within a certain parameter range. The maximum roll angle of vehicle body is mainly affected by the rut depth, and the rut width has a small effect on the vehicle driving stability. Meanwhile, considering human comfort, the rut side angle should not be greater than 1° when the rut depth reaches 2 cm. For autonomous driving, the rut depth should not exceed 2.5 cm. When the rut depth exceeds 2.5 cm, the vehicle body roll angle caused by the rut exceeds the inertial centrifugal force of the vehicle itself, which has a significant impact on the passenger comfort and safety.
Binshuang Zheng; XiaoMing Huang; Runmin Zhao; Zhengqiang Hong; Jiaying Chen; Shengze Zhu. Study on the Rut Control Threshold of Asphalt Pavement Considering Steering Stability of Autonomous Vehicles Based on Fuzzy Control Theory. Advances in Civil Engineering 2021, 2021, 1 -13.
AMA StyleBinshuang Zheng, XiaoMing Huang, Runmin Zhao, Zhengqiang Hong, Jiaying Chen, Shengze Zhu. Study on the Rut Control Threshold of Asphalt Pavement Considering Steering Stability of Autonomous Vehicles Based on Fuzzy Control Theory. Advances in Civil Engineering. 2021; 2021 ():1-13.
Chicago/Turabian StyleBinshuang Zheng; XiaoMing Huang; Runmin Zhao; Zhengqiang Hong; Jiaying Chen; Shengze Zhu. 2021. "Study on the Rut Control Threshold of Asphalt Pavement Considering Steering Stability of Autonomous Vehicles Based on Fuzzy Control Theory." Advances in Civil Engineering 2021, no. : 1-13.
This study aims to explore the possibility of utilizing limestone in porous asphalt concrete (PAC), targeting to the lower layer of the double-layer porous asphalt pavement. Limestone aggregate, which features relatively lower strength and desirable adhesion with asphalt, is used to replace basalt aggregate in PAC due to the shortage and high price of basalt. Both PAC with limestone and PAC with basalt are formulated with Marshall design method. Engineering performance evaluation verified that in comparison with PAC using basalt, PAC using limestone has less optimum asphalt content, lower Marshall compaction numbers, inferior drainage capacity, superior low-temperature cracking resistance, comparable rutting resistance and moisture stability, while satisfy the specification requirements. Furthermore, Superpave compaction model is employed to simulate the site compaction process. The results demonstrated that Superpave compaction process is divided into initial and over densification stages, in which the voids reduction in PAC with limestone is accelerated compared to that in PAC with basalt. The dynamic modulus of PAC increases with loading frequency, decreases with test temperature, and remarkably increases with gyration numbers. The master curves of dynamic modulus for PAC are constructed, which are approximately consistent for both PACs at equivalent compaction numbers. The tensile strength of PAC is found to increase with gyration numbers and both PACs present comparable tensile strength at the given compaction numbers. It is recommended to compact PAC using limestone with 40 gyrations. Therefore, limestone PAC with appropriate design and compaction parameters is prospective as the lower layer of the double-layer porous asphalt pavement.
Jianying Hu; Tao Ma; Yuhao Zhu; XiaoMing Huang; Jian Xu. A feasibility study exploring limestone in porous asphalt concrete: Performance evaluation and superpave compaction characteristics. Construction and Building Materials 2021, 279, 122457 .
AMA StyleJianying Hu, Tao Ma, Yuhao Zhu, XiaoMing Huang, Jian Xu. A feasibility study exploring limestone in porous asphalt concrete: Performance evaluation and superpave compaction characteristics. Construction and Building Materials. 2021; 279 ():122457.
Chicago/Turabian StyleJianying Hu; Tao Ma; Yuhao Zhu; XiaoMing Huang; Jian Xu. 2021. "A feasibility study exploring limestone in porous asphalt concrete: Performance evaluation and superpave compaction characteristics." Construction and Building Materials 279, no. : 122457.
The current study aims to examine the physical and rheological properties at the high-temperature range of 52, 58, 64, 70, 76, and 82°C, utilizing adjusted asphalt binders. Three kinds of asphalt modifiers were selected such as styrene-butadiene-styrene, ethylene vinyl acetate, and end of life tires. The selected additives were implemented with different contents ranging from 4% to 7% by the weight of neat asphalt. Various test methods have been established, such as ductility, viscosity, microscopic inspection, and dynamic shear rheometer experiments. Results proved that the percentage decrease in ductility was 93%, 91%, and 88% with regard to the adding of the end of life tires (ELTs), ethylene vinyl acetate (EVA), and styrene-butadiene-styrene (SBS) additives, respectively. Outcomes also confirmed that viscosity was boosted from 0.411 Pa.s to 1.249, 1.0986, and 0.9785 Pa.s after adding 7% of ELTs, 7% of EVA, and 7% of SBS, respectively. The rutting parameter and complex shear modulus increased after modification, indicating the excellent performance of asphalt. The conclusions confirmed that the ELTs have fewer agglomerates and have good compatibility before ageing and excellent compatibility after the ageing process. Thus, the ELTs are deemed as efficient dispersion additive for avoiding separation during the storage and handling of the asphalt binder. Lastly, ELTs were accepted as the best enhancer for their positive influence on physical and rheological characteristics, which means higher quality amended bitumen would give higher resistance to permanent deformation.
Ismail Bakheit Eldouma; Huang Xiaoming. Evaluation of the Additives’ Behaviour to Determine the Best Modifier for Improving Asphalt Performance at High Temperature. Advances in Civil Engineering 2021, 2021, 1 -10.
AMA StyleIsmail Bakheit Eldouma, Huang Xiaoming. Evaluation of the Additives’ Behaviour to Determine the Best Modifier for Improving Asphalt Performance at High Temperature. Advances in Civil Engineering. 2021; 2021 ():1-10.
Chicago/Turabian StyleIsmail Bakheit Eldouma; Huang Xiaoming. 2021. "Evaluation of the Additives’ Behaviour to Determine the Best Modifier for Improving Asphalt Performance at High Temperature." Advances in Civil Engineering 2021, no. : 1-10.
Porous asphalt mixture has been extensively exploited as a surfacing layer on highways because it contributes to controlling pavement runoff, enhancing driving safety, mitigating urban-heat island, and reducing tire-pavement noise. This study proposes a methodology to design two types of high-viscosity modified porous asphalt mixtures with target air voids of 20% and 22% (PAC-10 and PAC-16) for the double-layer porous asphalt pavement, involving in fabricating high-viscosity asphalt, formulating aggregate gradations, and optimizing asphalt-aggregate ratio. Firstly, high-viscosity asphalt was manufactured by incorporating high-viscosity modifier into the base asphalt by 12% and 15% (Base-12, Base-15) and crumb rubber-modified asphalt by 8% (CR-8). The physical properties, 60 °C dynamic viscosity, rotational viscosity and viscoelastic properties of high-viscosity asphalt were characterized. Next, based on orthogonal design method, two aggregate gradations were optimized for PAC-10 and PAC-16 mixtures. Furthermore, the Draindown and Cantabro tests were carried to determine the optimum asphalt-aggregate ratios. Finally, the performance metrics of air void content, permeability coefficient, high-temperature and low-temperature performance, and moisture susceptibility was evaluated on PAC-10 and PAC-16 mixtures. The results show that with the addition of high-viscosity modifier into asphalt binder, the softening point, ductility, 60 °C dynamic viscosity, rotational viscosity, complex shear modulus, phase angle, and rutting factor of the binder are increased while the penetration is decreased. The formula of voids volume of the mixture as a function of aggregate gradation is developed, which facilitates the determination of aggregate gradation. Furthermore, the optimum asphalt-aggregate ratio is found to be 4.7% for PAC-10 mixture and 4.1–4.4% for PAC-16 mixture. Both PAC-16 and PAC-10 mixtures with CR-8 are recommended to construct the double-layer porous asphalt pavement.
Jianying Hu; Tao Ma; Yuhao Zhu; XiaoMing Huang; Jian Xu; Libiao Chen. High-viscosity modified asphalt mixtures for double-layer porous asphalt pavement: Design optimization and evaluation metrics. Construction and Building Materials 2020, 271, 121893 .
AMA StyleJianying Hu, Tao Ma, Yuhao Zhu, XiaoMing Huang, Jian Xu, Libiao Chen. High-viscosity modified asphalt mixtures for double-layer porous asphalt pavement: Design optimization and evaluation metrics. Construction and Building Materials. 2020; 271 ():121893.
Chicago/Turabian StyleJianying Hu; Tao Ma; Yuhao Zhu; XiaoMing Huang; Jian Xu; Libiao Chen. 2020. "High-viscosity modified asphalt mixtures for double-layer porous asphalt pavement: Design optimization and evaluation metrics." Construction and Building Materials 271, no. : 121893.
Dowel bars are arranged between two slabs of jointed plain concrete pavements to transfer load between them. The looseness of these dowel bars leads to the decrease of the load transfer efficiency (LTE). Meanwhile, repeated vehicle load can result in void near the joints. In this paper, the behaviors of concrete pavement under the effect of void size and joint stiffness were studied by using ABAQUS software. The FEA model was calibrated for different element parameters based on mesh convergence analysis and validated by comparison with previous studies. The voids beneath slabs were considered in this study, including the loaded slab and unloaded slab. The different effects of base course modulus on the stress of loaded slab are also analysed. It is concluded that the results show that the void size and joint stiffness affect the stress of the loaded plate. Smaller void size and larger joint stiffness will lead to the maximum stress located at the bottom of the loaded slab, and the void size has little effect on the stress of the loaded slab. Otherwise, the larger void size will cause larger stress. The effect of base modulus on stress is similar.
Bangyi Liu; Yang Zhou; Linhao Gu; Dalin Wang; XiaoMing Huang. Mechanical Behavior of Concrete Pavement considering Void beneath Slabs and Joints LTE. Advances in Civil Engineering 2020, 2020, 1 -13.
AMA StyleBangyi Liu, Yang Zhou, Linhao Gu, Dalin Wang, XiaoMing Huang. Mechanical Behavior of Concrete Pavement considering Void beneath Slabs and Joints LTE. Advances in Civil Engineering. 2020; 2020 ():1-13.
Chicago/Turabian StyleBangyi Liu; Yang Zhou; Linhao Gu; Dalin Wang; XiaoMing Huang. 2020. "Mechanical Behavior of Concrete Pavement considering Void beneath Slabs and Joints LTE." Advances in Civil Engineering 2020, no. : 1-13.
Uneven support as result of voids beneath concrete slabs can lead to high tensile stresses at the corner of the slab and eventually cause many forms of damage, such as cracking or faulting. Three-dimensional (3D) finite element models of the concrete pavement with void are presented. Mesh convergence analysis was used to determine the element type and mesh size in the model. The accuracy of the model is verified by comparing with the calculation results of the code design standards in China. The reliability of the model is verified by field measurement. The analysis shows that the stresses are more affected at the corner of the slab than at the edge. Impact of void size and void depth at the slab corner on the slab stress are similar, which result in the change of the position of the maximum tensile stress. The maximum tensile stresses do not increase with the increase in the void size for relatively small void size. The maximum tensile stress increases rapidly with the enlargement in the void size when the size is ≥0.4 m. The increments of maximum tensile stress can reach 183.7% when the void size is 1.0 m. The increase in slab thickness can effectively reduce maximum tensile stress. A function is established to calculate the maximum tensile stress of the concrete slab. The function takes into account the void size, the slab thickness and the vehicle load. The reliability of the function was verified by comparing the error between the calculated and simulated results.
Bangyi Liu; Yang Zhou; Linhao Gu; XiaoMing Huang. Finite Element Simulation and Multi-Factor Stress Prediction Model for Cement Concrete Pavement Considering Void under Slab. Materials 2020, 13, 5294 .
AMA StyleBangyi Liu, Yang Zhou, Linhao Gu, XiaoMing Huang. Finite Element Simulation and Multi-Factor Stress Prediction Model for Cement Concrete Pavement Considering Void under Slab. Materials. 2020; 13 (22):5294.
Chicago/Turabian StyleBangyi Liu; Yang Zhou; Linhao Gu; XiaoMing Huang. 2020. "Finite Element Simulation and Multi-Factor Stress Prediction Model for Cement Concrete Pavement Considering Void under Slab." Materials 13, no. 22: 5294.
In order to investigate the contact behaviours of tire-pavement under dry condition, the finite element method was applied to establish the numerical model of the tire Bridgestone 205-55-R16 and textured asphalt pavement model . Based on the contact mechanics for elastic pavement, the contact model of three-dimensional tire-asphalt pavement was established according to Lagrangian algorithm. By considering the influence of pavement texture, the friction subroutine was compiled to calculate the tire-pavement adhesion coefficient. The influence of internal inflation pressure and wheel load on contact characteristics of tire-asphalt pavement were discussed respectively under static load and antilock braking system (ABS) state. The results show that when the slip rate is around 15%, the longitudinal adhesion coefficient of the tire reaches the maximum, which is in accordance with the setting of tire adhesion coefficient in tire science. When the tire is in emergency braking, the tire shoulder position and tread centre area are more susceptible to wear, and the contact pressure in centre area is biggest. Under the same wheel load and internal inflation pressure, the mean contact pressure increases by 8.4% and the contact area reduces by 7.7% when tire is at ABS state compared with the condition of static load.
Binshuang Zheng; Jiaying Chen; Runmin Zhao; Junyao Tang; Rongyan Tian; Shengze Zhu; XiaoMing Huang. Analysis of contact behaviour on patterned tire-asphalt pavement with 3-D FEM contact model. International Journal of Pavement Engineering 2020, 1 -16.
AMA StyleBinshuang Zheng, Jiaying Chen, Runmin Zhao, Junyao Tang, Rongyan Tian, Shengze Zhu, XiaoMing Huang. Analysis of contact behaviour on patterned tire-asphalt pavement with 3-D FEM contact model. International Journal of Pavement Engineering. 2020; ():1-16.
Chicago/Turabian StyleBinshuang Zheng; Jiaying Chen; Runmin Zhao; Junyao Tang; Rongyan Tian; Shengze Zhu; XiaoMing Huang. 2020. "Analysis of contact behaviour on patterned tire-asphalt pavement with 3-D FEM contact model." International Journal of Pavement Engineering , no. : 1-16.
Because of the direct contact between the tire and pavement, the skid resistance of asphalt pavement is a basic factor affecting the braking safety of autonomous vehicles. The road skid resistance mainly depends on the texture characteristics of the road surface. Considering the pavement friction characteristics, building a braking model of autonomous vehicles is an effective method to improve the braking safety of autonomous vehicles. In order to develop the safety braking method for autonomous vehicles based on the road surface friction characteristic, an automatic close-range photogrammetry system (ACRP system) was proposed and built based on the circle arranged three cameras close-range photogrammetry (CRP) technology to obtain the asphalt pavement surface texture accurately in real time. Automatic image acquisition and 3D reconstruction were achieved by the ACPR system. Sand patch testing method and laser scanning method (ZGScan) were applied to collect the on-site asphalt pavement texture comparing with the results of ACRP system. It shows the texture data obtained by ACPR system have relatively high accuracy and efficiency with recognition accuracy close to 0.02 mm. Then, the peak adhesion coefficients under different road conditions were calculated by considering the skid resistance contribution of the road surface texture. Based on CarSim/Simulink joint simulation, a braking model for autonomous vehicles was established. The characteristics of the autonomous vehicles during straight normal braking, emergency braking and driving on curved sections were analyzed. Then, the safety braking distance under different conditions was put forward. The research shows that the variation trends of friction coefficient curves under different pavement conditions (dry and wet pavement) are basically the same, which both decrease significantly with the increase of relative slipping ratio. When the speed exceeds 40 km/h, the curve tends to be gentle, indicating that the actual contact area of the tire-road comes to a stable status when the speed is relatively high. Based on the tire hydroplaning model built by ABAQUS, the peak adhesion coefficient curves for different pavement conditions were obtained. It can be seen that the peak adhesion coefficient of the road surface is convex parabolic distribution at different driving speeds. Moreover, the peak adhesion coefficient gradually decreases as the speed increases. During normal braking, the vehicle should keep relatively low braking deceleration considering passenger comfort. As for emergency braking, autonomous vehicle should be equipped with professional short-range radar, long-range radar and high-definition camera to detect the environment surrounding the vehicle. On rainy days, the braking distance is averagely increased by about 45% compared to sunny days. When the braking distance between vehicles is large enough, it is recommended to brake with a braking force of 4−6 MPa. Autonomous vehicles should keep a certain safe distance, which requires 1.1−1.2 times of the simulated average value of safety braking distance during the driving process on dry or wet pavement. As the radius of curved sections increases, the acceleration interference values under different road conditions basically reduce. When the radius is greater than or equal to100 m, the decrease rate of the acceleration interference value is more significant. In order to improve the braking comfort of the vehicles, the radius of the curved road should be controlled above 100 m. In this paper, the safety strategies for autonomous vehicles considering pavement surface texture characteristics can provide references for the theoretical design of braking system and braking safety evaluation for autonomous vehicles.
XiaoMing Huang; Yongmao Jiang; Binshuang Zheng; Runmin Zhao. Theory and methodology on safety braking of autonomous vehicles based on the friction characteristic of road surface. Chinese Science Bulletin 2020, 65, 3328 -3340.
AMA StyleXiaoMing Huang, Yongmao Jiang, Binshuang Zheng, Runmin Zhao. Theory and methodology on safety braking of autonomous vehicles based on the friction characteristic of road surface. Chinese Science Bulletin. 2020; 65 (30):3328-3340.
Chicago/Turabian StyleXiaoMing Huang; Yongmao Jiang; Binshuang Zheng; Runmin Zhao. 2020. "Theory and methodology on safety braking of autonomous vehicles based on the friction characteristic of road surface." Chinese Science Bulletin 65, no. 30: 3328-3340.
Cold recycling technique is an effective strategy of cost reduction, resource conservation and energy consumption in pavement maintenance and rehabilitation. However, the mechanical mechanism of cold recycled mixture is not clear in the process of strength formation. The research was to put forward practical suggestions for mechanical property improvement of cold recycled mixture and generalize the application more efficiently to reach an ultimate purpose of energy and resource conservation. Various mixing orders were designed to construct different interfacial features and reflect on mechanical properties, and two-phase “aggregate-binder” interfaces were considered as the main interface forms to respectively reveal the mechanical and microstructural characteristics of cold recycled mixture. The mechanical properties of different mixing orders were compared and analyzed by the indirect tensile tests and dynamic modulus tests. Besides, the microstructure was observed by scanning electron microscope and the backscattered images were captured to extract microvoid parameters. Results indicated that different mixing orders and interface forms had a great influence on the mechanical properties of cold recycled mixture. Within the range of binder content applied in cold recycled mixture, the strength of the interface involving the recycled asphalt particles was larger than that of the interface involving the new aggregates. The indirect tensile strength of the interface involving asphalt emulsion was larger than that of the interface involving cement, while the microvoidage was just on the contrary. In conclusion, mixing cement before adding asphalt emulsion is not conducive to the improvement of mechanical properties. It is suggested that cement and asphalt emulsion should be fully mixed before the contact between aggregate and mortar in order to realize the optimal performance of cold recycled mixture; otherwise, mineral aggregates mixed with asphalt emulsion first can also be a better alternative.
Tian Chen; Yingcheng Luan; Tao Ma; Junqing Zhu; XiaoMing Huang; Shijie Ma. Mechanical and microstructural characteristics of different interfaces in cold recycled mixture containing cement and asphalt emulsion. Journal of Cleaner Production 2020, 258, 120674 .
AMA StyleTian Chen, Yingcheng Luan, Tao Ma, Junqing Zhu, XiaoMing Huang, Shijie Ma. Mechanical and microstructural characteristics of different interfaces in cold recycled mixture containing cement and asphalt emulsion. Journal of Cleaner Production. 2020; 258 ():120674.
Chicago/Turabian StyleTian Chen; Yingcheng Luan; Tao Ma; Junqing Zhu; XiaoMing Huang; Shijie Ma. 2020. "Mechanical and microstructural characteristics of different interfaces in cold recycled mixture containing cement and asphalt emulsion." Journal of Cleaner Production 258, no. : 120674.
The air voids distribution has a significant effect on the pavement performance related distresses such as rutting, cracking, moisture damage and permeability. However, most studies only quantified the air voids by average content, ignoring the heterogeneity inside the materials. This study focuses on the heterogeneity of air voids distribution inside the open-grade asphalt mixture based on 2D image analysis. Equivalent aperture is proposed to measure the area of each air void. Results showed that along both vertical and horizontal sections inside the open-grade asphalt mixture, the number of voids with 0~2 mm equivalent aperture would have a great impact on the total number of voids, while large amounts of small voids would not significantly affect the total voids number. Additionally, voids with 0~4 mm equivalent aperture account for the largest proportion, and when the equivalent aperture is beyond 4 mm, the number of voids would decrease as the equivalent aperture increases, regardless of the void areas. Furthermore, in both vertical and horizontal sections, as the equivalent aperture increases, the speed to accumulate voids area would firstly increase and then decrease. As the equivalent aperture increases, the contribution to the total voids area would increase accordingly, and it would approach the peak when the equivalent aperture reaches about 8 mm.
Guangji Xu; Xiao Chen; XiaoMing Huang; Tao Ma; Wei Zhou. Characterization of Air Voids Distribution in the Open-Graded Asphalt Mixture Based on 2D Image Analysis. Applied Sciences 2019, 9, 4126 .
AMA StyleGuangji Xu, Xiao Chen, XiaoMing Huang, Tao Ma, Wei Zhou. Characterization of Air Voids Distribution in the Open-Graded Asphalt Mixture Based on 2D Image Analysis. Applied Sciences. 2019; 9 (19):4126.
Chicago/Turabian StyleGuangji Xu; Xiao Chen; XiaoMing Huang; Tao Ma; Wei Zhou. 2019. "Characterization of Air Voids Distribution in the Open-Graded Asphalt Mixture Based on 2D Image Analysis." Applied Sciences 9, no. 19: 4126.
Mechanical characteristics of the asphalt binders and mixtures were enhanced by utilising modifiers. The crumb rubber modifier has been introduced to the asphalt modification as an environmentally friendly procedure of scrap tires, to improve the mechanical characteristics of the asphalt. This study aims to modify the dry method for mixing crumb rubber modifier with asphalt and aggregate based on the binder mix design. To achieve this goal crumb rubber modified asphalt mixtures were prepared and tested by applying various tests such as Marshall Stability test, indirect tensile strength test, and wheel tracking test. Three mixing methods of CRM were studied regarding evaluating the stability, rutting, and moisture susceptibility. The crumb rubber modifier dry mixing method was modified and named the complex process. Better results were achieved for enhancing mechanical properties.
Ismail Bakheit; Huang Xiaoming. Modification of the dry method for mixing crumb rubber modifier with aggregate and asphalt based on the binder mix design. Construction and Building Materials 2019, 220, 278 -284.
AMA StyleIsmail Bakheit, Huang Xiaoming. Modification of the dry method for mixing crumb rubber modifier with aggregate and asphalt based on the binder mix design. Construction and Building Materials. 2019; 220 ():278-284.
Chicago/Turabian StyleIsmail Bakheit; Huang Xiaoming. 2019. "Modification of the dry method for mixing crumb rubber modifier with aggregate and asphalt based on the binder mix design." Construction and Building Materials 220, no. : 278-284.
When a fire takes place in a tunnel, the surface of the asphalt pavement will burn and release a large amount of smoke, which is toxic to human health. Thus, in order to prevent the combustion of the asphalt pavement under fire, it is necessary to propose some methods to retard its physical and chemical reaction under the high temperature. In this study, ten different combinations of fire retardants and a control case where no fire retardant was applied were prepared for evaluation. The thermogravimetric (TG)-mass spectrometry (MS) tests were used to evaluate their effect on the fire retardance from mass and energy perspectives and the Fire Dynamics Simulator (FDS) software was used to evaluate the fire retardance from temperature and smoke distribution perspectives. In experimental analysis, the TG (thermogravimetric) and DTG (differential thermogravimetric) curves were used to analyze the mass loss rate and residual mass of the asphalt and the activation energy was calculated and analyzed as well. In addition, decay rate of mass loss rate and increasing rate of activation energy were proposed to evaluate the ease of combustion of the asphalt with and without fire retardants. The results show that in laboratory experiments, the fire retardant combination which includes 48% aluminum hydroxide, 32% magnesium hydroxide, 5% expanded graphite, and 15% encapsulated red phosphorous would lead to an improved effect of fire retardance. In numerical modeling, the temperature and smoke height distribution over time were adopted to evaluate the fire retardance effect. The temperature distribution was found to be symmetrical on both sides of the combustion point and the same combination as proposed in experimental analysis was found to have the best effect on fire retardance due to the largest decrease in temperature. Additionally, because of the highest smoke height distribution, an improved effect on smoke suppression was also found when this combination was applied.
Guangji Xu; Xiao Chen; Shichao Zhu; Lingdi Kong; XiaoMing Huang; Jiewen Zhao; Tao Ma; Xu; Chen; Zhu; Kong; Zhao; Ma. Evaluation of Asphalt with Different Combinations of Fire Retardants. Materials 2019, 12, 1283 .
AMA StyleGuangji Xu, Xiao Chen, Shichao Zhu, Lingdi Kong, XiaoMing Huang, Jiewen Zhao, Tao Ma, Xu, Chen, Zhu, Kong, Zhao, Ma. Evaluation of Asphalt with Different Combinations of Fire Retardants. Materials. 2019; 12 (8):1283.
Chicago/Turabian StyleGuangji Xu; Xiao Chen; Shichao Zhu; Lingdi Kong; XiaoMing Huang; Jiewen Zhao; Tao Ma; Xu; Chen; Zhu; Kong; Zhao; Ma. 2019. "Evaluation of Asphalt with Different Combinations of Fire Retardants." Materials 12, no. 8: 1283.
The overall objectives of this study were to determine the most appropriate additive for improving the physical properties and the medium- and high-temperature performances (mechanical performance) of asphalt binders. Three different types of modified binders were prepared: crumb rubber modifier (CRM), polypropylene (PP), and tafpack super (TPS), which had concentrations of 2%, 3%, 3.5%, and 4% by weight of asphalt binder, for each modifier. Their physical and rheological properties were evaluated by applying various tests such as ductility, rotational viscosity, toughness, and tenacity, as well as the dynamic shear rheometer (DSR) test. As a result, the physical properties of the modified bitumen binders were compared, as were the medium- and high-temperature performances (mechanical performance), which had temperatures of 58, 64, 70, 76, 82, and 88 °C, respectively. This was how the most appropriate modifier was determined. The results demonstrated that the asphalt binder properties significantly improved by utilizing CRM followed by PP and TPS modifiers. The increase in the rutting parameter (G*/sin(δ)) after asphalt modification indicated its excellent performance at both medium- and high-temperatures. Lastly, the CRM was determined as the most preferred additive because of its positive effect on the physical properties and enhancement of the medium- and high-temperature performance (mechanical performance).
Huang Xiaoming; Ismail Bakheit Eldouma. Experimental Study to Determine the Most Preferred Additive for Improving Asphalt Performance Using Polypropylene, Crumb Rubber, and Tafpack Super in Medium and High-Temperature Range. Applied Sciences 2019, 9, 1567 .
AMA StyleHuang Xiaoming, Ismail Bakheit Eldouma. Experimental Study to Determine the Most Preferred Additive for Improving Asphalt Performance Using Polypropylene, Crumb Rubber, and Tafpack Super in Medium and High-Temperature Range. Applied Sciences. 2019; 9 (8):1567.
Chicago/Turabian StyleHuang Xiaoming; Ismail Bakheit Eldouma. 2019. "Experimental Study to Determine the Most Preferred Additive for Improving Asphalt Performance Using Polypropylene, Crumb Rubber, and Tafpack Super in Medium and High-Temperature Range." Applied Sciences 9, no. 8: 1567.
In order to obtain the asphalt pavement texture information in real time and accurately monitor the anti-skid performance of the road pavement, an automatic close range photogrammetry system (ACPR system) was proposed and built based on the circle arranged three cameras close range photogrammetry (CPR) technology to obtain the asphalt pavement surface texture. Automatic image acquisition and 3D reconstruction were achieved by the ACPR system. Sand patch method and laser scanning method (ZGScan) were used to collect the on-site comparison test of the asphalt pavement texture. Mean texture depth (MTD) and root mean square roughness (RSMR) were chosen as the statistical indicators of road surface texture. The results show that the texture data obtained by ACPR system has relatively high accuracy and efficiency, and the recognition accuracy is close to 0.02mm. The ACPR system improves the efficiency and accuracy of traditional close range photogrammetry and provides real-time and effective road surface anti-skid information for subsequent safety braking of autonomous vehicle.
Chen Jiaying; Zheng Binshuang; Chen Xi; Zhao Runmin; Huang Xiaoming. Acquisition method of asphalt pavement texture information based on the CPR Technology. MATEC Web of Conferences 2019, 275, 04003 .
AMA StyleChen Jiaying, Zheng Binshuang, Chen Xi, Zhao Runmin, Huang Xiaoming. Acquisition method of asphalt pavement texture information based on the CPR Technology. MATEC Web of Conferences. 2019; 275 ():04003.
Chicago/Turabian StyleChen Jiaying; Zheng Binshuang; Chen Xi; Zhao Runmin; Huang Xiaoming. 2019. "Acquisition method of asphalt pavement texture information based on the CPR Technology." MATEC Web of Conferences 275, no. : 04003.
This paper proposes a new modeling method to reconstruct hollow shapes of aggregate particles using the discrete-element method (DEM) to accurately characterize the microstructures of aggregates and efficiently predict the mechanical properties of aggregate skeletons. To provide a basis for virtual aggregate reconstruction, two-dimensional images and key morphological characteristics of different aggregate particles are measured using the Aggregate Imaging Measurement System (AIMS). Three different modeling methods—radius-expansion (RE), interior-filling (IF), and contour-filling (CF)—are applied using Particle Flow Code in Two Dimensions (PFC2D) discrete-element software. Whereas RE and IF are conventional methods, the CF method is newly developed for this study. Both laboratory penetration and DEM-based virtual penetration tests are conducted to determine the microparameters for different aggregates. Further virtual penetration tests are then conducted to predict the inner friction resistance of different aggregate skeletons and to compare the accuracy and efficiency of the respective modeling methods. Based on these macromechanical and micromechanical property analyses, it is demonstrated that the newly developed CF modeling method is much more accurate and efficient than the conventional RE and IF methods, respectively.
Xunhao Ding; Tao Ma; XiaoMing Huang. Discrete-Element Contour-Filling Modeling Method for Micromechanical and Macromechanical Analysis of Aggregate Skeleton of Asphalt Mixture. Journal of Transportation Engineering, Part B: Pavements 2019, 145, 04018056 .
AMA StyleXunhao Ding, Tao Ma, XiaoMing Huang. Discrete-Element Contour-Filling Modeling Method for Micromechanical and Macromechanical Analysis of Aggregate Skeleton of Asphalt Mixture. Journal of Transportation Engineering, Part B: Pavements. 2019; 145 (1):04018056.
Chicago/Turabian StyleXunhao Ding; Tao Ma; XiaoMing Huang. 2019. "Discrete-Element Contour-Filling Modeling Method for Micromechanical and Macromechanical Analysis of Aggregate Skeleton of Asphalt Mixture." Journal of Transportation Engineering, Part B: Pavements 145, no. 1: 04018056.
The gradation and mechanical properties of aggregates impressively affect the load carrying capacity and rutting resistance of asphalt mixtures. They are able to provide some fundamental parameters that are linked to mixture performance. In order to accurately detect critical controlled sizes and obtain more fundamental parameters that can characterize load carrying capacity and rutting resistance of asphalt mixtures, this paper aims to develop a mechanics-based approach to evaluate aggregate gradation, which contains the theoretical packing analysis and discrete element simulation. An extended theoretical morphology framework is developed by checking the local and global interlock of graded aggregates in the theoretical packing analysis. The sieve size range of primary structure which has an interactive interlock can be determined in the local interlock check model. The relationship between the transferred force and the induced force is proposed in the densest and loosest packing arrangements, respectively. The morphological parameters of disruption factor and weighted average size for the global scale are also proposed in theoretical packing analysis. Then the discrete element method is used to validate the theoretical framework. The advanced gradation input algorithm procedure is established in the discrete element simulation to simulate the compression test of graded aggregates. The mechanical parameters of contact force, contact points and stress–strain curves are extracted from the simulation results. The results show that the discrete element method can validate the theoretical framework and output the performance related parameters. The contact force analysis shows that the aggregates retaining on sieve sizes of 2.36 and 4.75 mm provide more than 50% contribution to resist load, and the aggregates retaining on sieve sizes of 1.18, 0.6 and 0.3 mm provide more than 50% contribution to stabilize the structure. The coordination number analysis suggests that the gradation with more fine aggregates might lead to a greater number of voids but smaller air-void size when the asphalt content and porosity remain constant. The stress–strain curve analysis shows that the modulus and secondary strain are highly related to the rutting performance of an asphalt mixture.
Yao Zhang; Xue Luo; Ibrahim Onifade; XiaoMing Huang; Robert L. Lytton; Bjorn Birgisson. Mechanical evaluation of aggregate gradation to characterize load carrying capacity and rutting resistance of asphalt mixtures. Construction and Building Materials 2019, 205, 499 -510.
AMA StyleYao Zhang, Xue Luo, Ibrahim Onifade, XiaoMing Huang, Robert L. Lytton, Bjorn Birgisson. Mechanical evaluation of aggregate gradation to characterize load carrying capacity and rutting resistance of asphalt mixtures. Construction and Building Materials. 2019; 205 ():499-510.
Chicago/Turabian StyleYao Zhang; Xue Luo; Ibrahim Onifade; XiaoMing Huang; Robert L. Lytton; Bjorn Birgisson. 2019. "Mechanical evaluation of aggregate gradation to characterize load carrying capacity and rutting resistance of asphalt mixtures." Construction and Building Materials 205, no. : 499-510.
The particle clustering phenomena in reclaimed asphalt pavement (RAP) particles is one of the most important factors to affect the efficient recycling of asphalt concrete. In this study, the particle composition, clustering degree, crushing properties and clustering stability of RAP were studied by extraction test and cantabro-crushing test. It was found that the particles above 4.75 mm were composed mainly of small particles with a large degree of cluster and poor stability. The coarse particles (>4.75 mm) had a great influence on the variation of 4.75 mm sieve. Quantitative indexes of Percentage Loss rate (PL) and Stability Index (w) were proposed to evaluate the clustering degree and the stability of RAP. It provided a meaningful reference for the comparison of different RAP and the different crushing processes. In addition, the RAP could be divided into three kinds of structures, including weak cluster structure, strong cluster structure and old aggregate. The process of crushing the RAP was divided into three stages, which are weak structure-dominated, strong structure-dominated and the broken old aggregate. The weak structure had the largest degree of cluster and worst stability, resulting in a large variability of RAP, and it should be avoided in the crushing process.
Guangji Xu; Tao Ma; Zhanyong Fang; XiaoMing Huang; Weiguang Zhang. The Evaluation Method of Particle Clustering Phenomena in RAP. Applied Sciences 2019, 9, 424 .
AMA StyleGuangji Xu, Tao Ma, Zhanyong Fang, XiaoMing Huang, Weiguang Zhang. The Evaluation Method of Particle Clustering Phenomena in RAP. Applied Sciences. 2019; 9 (3):424.
Chicago/Turabian StyleGuangji Xu; Tao Ma; Zhanyong Fang; XiaoMing Huang; Weiguang Zhang. 2019. "The Evaluation Method of Particle Clustering Phenomena in RAP." Applied Sciences 9, no. 3: 424.