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This paper presents an experimental investigation on the performance of cement stabilized recycled mixture containing recycled concrete aggregate (RCA) and crushed brick (RCB), which are separated from recycled aggregate. Firstly, basic material performance tests were conducted to establish a comparison among natural aggregate and recycled aggregate (RA). To reveal the mechanism of cement stabilized mixtures in strength formation, Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) tests were carried out in specimens of 3 different ages (9 d, 28 d, 90 d). Subsequently, unconfined compressive strength tests, splitting strength and compressive modulus tests, were undertaken in five contents of RA by weight (0%, 25%, 50%, 75%, 100%). In each grade of RA content, three different ratios of RCB/RCA (1:9, 3:7, 5:5) were considered. Afterward, the fuzzy set method was used to rank these schemes and evaluate the mechanical property of specimens. It can be found that the mechanical properties of cement-stabilized mixtures change linearly with the proportion of RA at 25% and 50%, sharply decreased from 50% to 75%. With the RA content increasing, the effect of RCB content on pavement performance gradually decreases. Finally, by taking the results of dry and temperature shrinkage testes into consideration, it was concluded that the amount of RA should not exceed 50%, the ratio of RCB/RCA should not exceed 3:7 in the road construction. In that way, it can meet the requirements of the sub-base of expressways and first-class highways in China when the cement dosage is setting to 4%.
Junhui Zhang; Cheng Li; Le Ding; Jian Li. Performance evaluation of cement stabilized recycled mixture with recycled concrete aggregate and crushed brick. Construction and Building Materials 2021, 296, 123596 .
AMA StyleJunhui Zhang, Cheng Li, Le Ding, Jian Li. Performance evaluation of cement stabilized recycled mixture with recycled concrete aggregate and crushed brick. Construction and Building Materials. 2021; 296 ():123596.
Chicago/Turabian StyleJunhui Zhang; Cheng Li; Le Ding; Jian Li. 2021. "Performance evaluation of cement stabilized recycled mixture with recycled concrete aggregate and crushed brick." Construction and Building Materials 296, no. : 123596.
Recycling construction and demolition (C&D) waste as fillers in pavement subgrade is a sustainable paving technology with environmental and economic merits. The performance of pavement subgrade with C&D waste depends on its dynamic resilient modulus. Meanwhile, freeze–thaw cycles are also an important issue for engineering in seasonal frozen regions. However, research on characteristics of the dynamic resilient modulus of C&D waste, especially the properties under freeze–thaw cycles, is limited. To this end, this study aims to reveal the variation law of the dynamic resilient modulus of C&D waste under repeated freeze–thaw cycles and establish a reasonable performance prediction model. This study conducts a series of laboratory tests after various freeze–thaw cycles. Results indicate that the soil–water characteristic curves of C&D waste with different compactness and number of freeze–thaw cycles can be well described by Van Genuchten’s model. Moreover, the dynamic resilient modulus enhances with the increase of matric suction, compactness, deviator stress and minimum bulk stress and exhibits a stress-hardening characteristic. Freeze–thaw cycles attenuate the matric suction and dynamic resilient modulus of C&D waste. Besides, high moisture contents, low stress levels and more freeze–thaw cycles all aggravate the attenuation of the dynamic resilient modulus in certain extent, but the attenuation is not sensitive to the compactness. Finally, this study establishes a high-accuracy prediction model of the dynamic resilient modulus considering the effect of repeated freeze–thaw cycles. This study can supply useful information on the application of C&D waste in pavement subgrade in seasonal frozen regions.
Junhui Zhang; Anshun Zhang; Chao Huang; Huayang Yu; Chao Zhou. Characterising the resilient behaviour of pavement subgrade with construction and demolition waste under Freeze–Thaw cycles. Journal of Cleaner Production 2021, 300, 126702 .
AMA StyleJunhui Zhang, Anshun Zhang, Chao Huang, Huayang Yu, Chao Zhou. Characterising the resilient behaviour of pavement subgrade with construction and demolition waste under Freeze–Thaw cycles. Journal of Cleaner Production. 2021; 300 ():126702.
Chicago/Turabian StyleJunhui Zhang; Anshun Zhang; Chao Huang; Huayang Yu; Chao Zhou. 2021. "Characterising the resilient behaviour of pavement subgrade with construction and demolition waste under Freeze–Thaw cycles." Journal of Cleaner Production 300, no. : 126702.
The paper presents an analytical solution for the vertical dynamic interaction analysis of a poroelastic soil layer and an embedded pile with the consideration of pile-soil radial deformations. The soil is treated a three-dimensional porous continuum and described by the Boer’s poroelastic model, while the pile is treated as a two-dimensional rod with both radial and vertical deformations of which the equation of motion is derived by the Hamilton’s variational principle. Without the introduction of potential functions, first take the volumetric strain of soil skeleton and pore fluid pressure as intermediate variables to deal with the equations of motion for the soil and then use the separation of variables to solve the equations of motion for the soil and the pile. By imposing the boundary and continuity conditions of the pile-soil system, the dynamic impedance in frequency domain and the velocity response in time domain of the pile top are obtained. The present solution is then verified by comparing with the corresponding finite element model computation results and the existing solutions. The effects of the pile-soil parameters on the dynamic characteristic of the pile-soil system are also analyzed. Some significant conclusions are drawn, which can provide useful reference for related engineering practice.
Shiping Zhang; Junhui Zhang; Yongbo Ma; Ronald Y.S. Pak. Vertical dynamic interactions of poroelastic soils and embedded piles considering the effects of pile-soil radial deformations. Soils and Foundations 2020, 61, 16 -34.
AMA StyleShiping Zhang, Junhui Zhang, Yongbo Ma, Ronald Y.S. Pak. Vertical dynamic interactions of poroelastic soils and embedded piles considering the effects of pile-soil radial deformations. Soils and Foundations. 2020; 61 (1):16-34.
Chicago/Turabian StyleShiping Zhang; Junhui Zhang; Yongbo Ma; Ronald Y.S. Pak. 2020. "Vertical dynamic interactions of poroelastic soils and embedded piles considering the effects of pile-soil radial deformations." Soils and Foundations 61, no. 1: 16-34.
To better control the strength and deformation of the roadbed, a constitutive model of rockfill was established based on property-dependent plastic potential theory for geomaterials. The effect of the particle gradation on the anisotropy was described in the model. According to the effect of the particle grading and crushing on the fractal dimension, the fractal theory and fabric tensor were introduced to establish the yield and failure criteria of the rockfill. By combining the property-dependent concepts of the materials and the results of the rockfill strength test, a critical state line considering the microstructure, fractal dimension, particle breakage, and stress state of the rockfill was established. The dilatancy equation was derived based on the novel potential theory and the hardening criterion affected by the critical state was established. A constitutive model of the rockfill in the general stress space was established under the framework of the novel potential theory. The 3D strength and its intensity change in the π plane were simulated through the drainage strength test results, which verified the description of the critical state under various stress paths. By simulating the stress-strain relationship, the validity and rationality of the model were verified.
Xuefeng Li; Ruijie Li; Junhui Zhang; Qi Wang. The Constitutive Model of Rockfill Based on Property-Dependent Plastic Potential Theory for Geomaterials. Advances in Civil Engineering 2020, 2020, 1 -13.
AMA StyleXuefeng Li, Ruijie Li, Junhui Zhang, Qi Wang. The Constitutive Model of Rockfill Based on Property-Dependent Plastic Potential Theory for Geomaterials. Advances in Civil Engineering. 2020; 2020 ():1-13.
Chicago/Turabian StyleXuefeng Li; Ruijie Li; Junhui Zhang; Qi Wang. 2020. "The Constitutive Model of Rockfill Based on Property-Dependent Plastic Potential Theory for Geomaterials." Advances in Civil Engineering 2020, no. : 1-13.
In the system formed by bituminous crack sealant and the crack wall, the contact area of aggregate and sealant is maximum, and types and properties of aggregate have an obvious influence on the adhesion of the sealant. To quantitatively evaluate the adhesion of sealant to aggregate, based on the surface energy theory, the surface energy and its components of sealant and aggregate were determined and calculated using the sessile drop method. Then, the adhesion work of different types of sealants and aggregates was calculated. The correlation of adhesion work was verified by the improved boiling method test and scanning electron microscope (SEM) test. Results show that surface energy of the aggregate is obviously higher than that of the sealant. The relationship of surface energy of raw materials is granite>diabase>basalt>Sealant A (type JG-10; Beijing Jiageweiye Company) > Sealant C (type II; American Crafco Company) > Sealant B (type JSD; JSD Corporation of Japan). The relationship of adhesion work of different sealants with the same aggregate is Sealant A > Sealant C > Sealant B, indicating that the adhesion of Sealant A to aggregate is better than that of Sealant B and Sealant C. Results of the improved boiling method test show that the coefficient of linear correlation between the mass loss rate of sealant and the adhesion work is as high as 0.9308, indicating that there is a good linear relationship between them. The SEM results show that the adhesion work is consistent with the actual adhesion state of the interface, which shows that the adhesion work index can be used to characterize the adhesion of sealant to aggregate.
Zhilin Sun; Sitong Li; Junhui Zhang; Yi Zeng. Adhesion of Bituminous Crack Sealants to Aggregates Using Surface Energy Theory. Journal of Materials in Civil Engineering 2020, 32, 04020299 .
AMA StyleZhilin Sun, Sitong Li, Junhui Zhang, Yi Zeng. Adhesion of Bituminous Crack Sealants to Aggregates Using Surface Energy Theory. Journal of Materials in Civil Engineering. 2020; 32 (10):04020299.
Chicago/Turabian StyleZhilin Sun; Sitong Li; Junhui Zhang; Yi Zeng. 2020. "Adhesion of Bituminous Crack Sealants to Aggregates Using Surface Energy Theory." Journal of Materials in Civil Engineering 32, no. 10: 04020299.
This paper presents a new model for modulus back-calculation for high liquid limit clay subgrades. In this model, the viscoelasticity theory is employed to describe the displacement hysteresis, and the multipopulation genetic algorithm (MPGA) is used to iterate the optimal results. The reliability and precision of the proposed back-calculation model are confirmed by finite element (FE) simulations and in situ tests. Based on the new method, 12 sets of results from FE simulations show that the correlation coefficient between the time-history curve of displacement and the real curve can be ≥0.99, where the calculation error is < 4%. Further, through comparative studies, it is found that the new calculation method works better in convergence speed and adaptability than the traditional method and plays a very useful role in subgrade design and construction quality control.
Junhui Zhang; Haishan Fan; Shiping Zhang; Jie Liu; Junhui Peng. Back-Calculation of Elastic Modulus of High Liquid Limit Clay Subgrades Based on Viscoelastic Theory and Multipopulation Genetic Algorithm. International Journal of Geomechanics 2020, 20, 04020194 .
AMA StyleJunhui Zhang, Haishan Fan, Shiping Zhang, Jie Liu, Junhui Peng. Back-Calculation of Elastic Modulus of High Liquid Limit Clay Subgrades Based on Viscoelastic Theory and Multipopulation Genetic Algorithm. International Journal of Geomechanics. 2020; 20 (10):04020194.
Chicago/Turabian StyleJunhui Zhang; Haishan Fan; Shiping Zhang; Jie Liu; Junhui Peng. 2020. "Back-Calculation of Elastic Modulus of High Liquid Limit Clay Subgrades Based on Viscoelastic Theory and Multipopulation Genetic Algorithm." International Journal of Geomechanics 20, no. 10: 04020194.
Studies associated with dynamic plate–medium interactions generally assumed the plate structures to be permeable for the sake of convenience. But the effect and applicability of such an assumption are still unclear, and then the pore fluid pressure on the plate and medium interfaces cannot be obtained. In this paper, the mentioned problems are discussed by studying the coupling steady-state vibration of an impermeable, rigid, circular plate resting on a finite, fluid-saturated, poroelastic soil layer underlain by rigid base and subjected to a vertical time-harmonic loading. The semi-analytical solutions for the dynamic compliance, displacements, stresses, especially the contact stress including effective stress and pore fluid pressure of the plate and the layer, are proposed. In developing these solutions, the linearly poroelastic model established by de Boer is used to describe the mechanical behaviour of the porous medium. By means of four scalar displacement potentials and the Fourier–Hankel transformation to solve the equations of motion of the poroelastic layer, and then imposing boundary and interfacial conditions, a pair of coupling Fredholm’s integral equations of the second kind formulating the plate–medium interaction are derived and evaluated with numerical methods. The proposed solutions are then verified by comparing with the existing special solutions and the FEM calculation results. Numerical examples are also performed to examine the effects of the permeability of both the plate and the poroelastic layer and the thickness of the layer on the dynamic response of the coupling system.
Shiping Zhang; Ronald Y. S. Pak; Junhui Zhang. Vertical time-harmonic coupling vibration of an impermeable, rigid, circular plate resting on a finite, poroelastic soil layer. Acta Geotechnica 2020, 16, 911 -935.
AMA StyleShiping Zhang, Ronald Y. S. Pak, Junhui Zhang. Vertical time-harmonic coupling vibration of an impermeable, rigid, circular plate resting on a finite, poroelastic soil layer. Acta Geotechnica. 2020; 16 (3):911-935.
Chicago/Turabian StyleShiping Zhang; Ronald Y. S. Pak; Junhui Zhang. 2020. "Vertical time-harmonic coupling vibration of an impermeable, rigid, circular plate resting on a finite, poroelastic soil layer." Acta Geotechnica 16, no. 3: 911-935.
In terms of longer hardening time of emulsified asphalt seal mixture, a rapid hardening seal mixture was prepared by adding cement and carbon fibre to the Styrene–Butadiene-Rubber (SBR)-modified emulsified asphalt. The mix proportion of mixture was determined by testing the mixable time, consistency, wet track abrasion value, adhered sand content, cohesion force and the cracking rate. The microscopic mechanisms of rapid hardening and cracking control were studied using the Scanning Electron Microscopy (SEM) and the Fourier Transform Infrared Spectroscopy (FTIR). It is found that the optimum contents of SBR-modified emulsified asphalt, added water, cement and carbon fibre in the prepared mixture are 12%, 13%, 4% and 4%, respectively. At 20°C, with a relative humidity of 90% and a wind speed of 10 km/h, the opening time to traffic of mixture adding 4% ordinary Portland cement can be 2 h earlier than that without cement.
Zhilin Sun; Shuaijie Ma; Junhui Zhang; Fuan Sun. Microstructure characterisation and performance investigation of a rapid hardening emulsified asphalt seal mixture. Road Materials and Pavement Design 2020, 1 -16.
AMA StyleZhilin Sun, Shuaijie Ma, Junhui Zhang, Fuan Sun. Microstructure characterisation and performance investigation of a rapid hardening emulsified asphalt seal mixture. Road Materials and Pavement Design. 2020; ():1-16.
Chicago/Turabian StyleZhilin Sun; Shuaijie Ma; Junhui Zhang; Fuan Sun. 2020. "Microstructure characterisation and performance investigation of a rapid hardening emulsified asphalt seal mixture." Road Materials and Pavement Design , no. : 1-16.
Construction and demolition waste contain large amount of concrete and bricks. To identify its feasibility of applying in asphalt stabilized gravel mixtures as pavement base, this paper carried out researches on properties of recycled asphalt mixture (RAM) by laboratory testing, under different contents of recycled aggregates (RA) and proportions of bricks to concrete. First, the basic physical properties of each component of the RAM were determined. According to the actual screening passing rate, the Bailey method was used to design and verify the grading of RAM, and then initial asphalt content was estimated. The stability, flow value, voidage, and bulk density were obtained by Marshall Test, and the optimal asphalt-aggregate ratios were determined under different RA contents and proportion of bricks to concrete. Subsequently, the uniaxial compression test, splitting tensile test, immersion Marshall test, freeze-thaw splitting test, and Hamburg rutting test were performed to investigate mechanical properties, water stability, and high-temperature stability of RAM. The results shows that as the content of RA increases from 0% to 100%, the corresponding compressive strength, resilient modulus, and splitting tensile strength all decrease; the same change trend is presented in the residual stability and freeze-thaw splitting test strength ratio and rutting depth. According to the requirement of pavement base of high-grade roads in China’s standards, the recommended RA content and proportion of bricks to concrete were proposed for the design RAM.
Le Ding; Junhui Zhang; Bowen Feng; Cheng Li. Performance Evaluation of Recycled Asphalt Mixtures Containing Construction and Demolition Waste Applicated as Pavement Base. Advances in Civil Engineering 2020, 2020, 1 -11.
AMA StyleLe Ding, Junhui Zhang, Bowen Feng, Cheng Li. Performance Evaluation of Recycled Asphalt Mixtures Containing Construction and Demolition Waste Applicated as Pavement Base. Advances in Civil Engineering. 2020; 2020 ():1-11.
Chicago/Turabian StyleLe Ding; Junhui Zhang; Bowen Feng; Cheng Li. 2020. "Performance Evaluation of Recycled Asphalt Mixtures Containing Construction and Demolition Waste Applicated as Pavement Base." Advances in Civil Engineering 2020, no. : 1-11.
In order to quantitatively evaluate the adhesion property of bituminous crack sealants to the crack walls formed by different types of asphalt mixtures, the surface energy components of raw materials were determined by the sessile drop method. Then the adhesion work of sealants and pavement materials was calculated respectively. The correlation between indexes of adhesion work was verified by quantitative boiling method and scanning electron microscope (SEM) test. Finally, four kinds of mixture specimens were formed, and the geometrical information of cross-section of mixture was extracted based on the digital image processing (DIP) technique. The weighted average adhesion work of the cross-section was calculated and verified by the shear tests. The test results show that the surface energy of basalt is obviously higher than that of the SBS modified asphalt and sealant. Among the components of surface energy of three materials, the dispersion component is dominant. The adhesion work of sealant and aggregate is higher than that of SBS modified asphalt. Test results of quantitative boiling method show that there is a good linear relationship between the mass loss rate of the sealant and the index of the adhesion work. The determination coefficient is as high as 0.96, indicating that the index of adhesion work can accurately characterize the adhesion performance of sealant and aggregate. DIP test results show that the aggregate of four mixtures accounts for the largest area, which exceeds 71% of total area. The relationship between the weighted average adhesion work of four mixtures and sealant A is AC-13 > AC-25 > SMA-13 > AC-20, which is consistent with results of the shear tests. The determination coefficient of linear correlation is 0.8672, which indicates that the proposed weighted average adhesion work can accurately characterize the actual adhesion state of interface.
Zhilin Sun; Sitong Li; Junhui Zhang; Yi Zeng. Adhesion property of bituminous crack sealants to different asphalt mixtures based on surface energy theory. Construction and Building Materials 2020, 261, 120006 .
AMA StyleZhilin Sun, Sitong Li, Junhui Zhang, Yi Zeng. Adhesion property of bituminous crack sealants to different asphalt mixtures based on surface energy theory. Construction and Building Materials. 2020; 261 ():120006.
Chicago/Turabian StyleZhilin Sun; Sitong Li; Junhui Zhang; Yi Zeng. 2020. "Adhesion property of bituminous crack sealants to different asphalt mixtures based on surface energy theory." Construction and Building Materials 261, no. : 120006.
Ponded infiltration is very common in silty mudstone and has a great influence on the stability of related slopes, road cuttings, and tunnels. This paper aims to examine the infiltration performance of silty mudstone and predict the distribution of its water content under ponded conditions. By infiltration tests, the infiltration rate (i), cumulative infiltration (I), and their variations with the infiltration time (t) were obtained. Afterward, the variation of water content (w) with t and depth (s) was analyzed. The results show that the i value decreases with the increase in the degree of saturation, and the I value increases first significantly and then slightly during water infiltration. The entire w–t curve at any s is S-shaped, while the w–s curve at any t is full or half inverse-S-shaped. In addition, an equation was developed for the w–s prediction based on the simplified Gompertz curve model, and it was further extended to the spatial–temporal prediction model of water content. The evaluation results demonstrate that the spatial–temporal prediction model has high accuracy and reliability. The prediction model also indicates that the range of the infiltration-affected zone increases and the rate of increase slows down during water infiltration.
Ling Zeng; Xiaofei Yao; Junhui Zhang; Qian-Feng Gao; Jingcheng Chen; Yutong Gui. Ponded infiltration and spatial–temporal prediction of the water content of silty mudstone. Bulletin of Engineering Geology and the Environment 2020, 79, 5371 -5383.
AMA StyleLing Zeng, Xiaofei Yao, Junhui Zhang, Qian-Feng Gao, Jingcheng Chen, Yutong Gui. Ponded infiltration and spatial–temporal prediction of the water content of silty mudstone. Bulletin of Engineering Geology and the Environment. 2020; 79 (10):5371-5383.
Chicago/Turabian StyleLing Zeng; Xiaofei Yao; Junhui Zhang; Qian-Feng Gao; Jingcheng Chen; Yutong Gui. 2020. "Ponded infiltration and spatial–temporal prediction of the water content of silty mudstone." Bulletin of Engineering Geology and the Environment 79, no. 10: 5371-5383.
With the rapid advancement of urbanization in China, a huge amount of construction and demolition wastes (CDW) are generated. Recycling CDW into subgrade materials is a promising way to process these wastes, with significant environmental and economic benefits. But very little work has been done in this field. Therefore, based on a CDW subgrade construction case in Beijing, the physical and chemical properties of the CDW materials were analyzed. Then the construction procedures of the CDW subgrade were presented, and a series of tests (compaction degree test, settlement observation, Portable Falling Weight Deflectometer test) were carried out. At the same time, the effects of different loose paving thicknesses, cycles of strong vibration on the subgrade performances were assayed. Subsequently, grading analysis of the CDW particles, plate load test and Beckman beam deflection test were performed to evaluate the construction quality. According to the test results, the construction technologies of the CDW subgrade, such as the optimum loose paving thicknesses and cycles of strong vibration, were determined. And then, the post-construction settlement monitor and radar survey were conducted for subgrades filled with CDW and soil to further analyze the applicability of CDW. The results show that recycled CDW aggregates with proper grading and strict construction technologies perform well. The subgrade filled with recycled CDW has a smaller deformation than that of the soil subgrade. Finally, the life cycle assessments (LCA) of two treating schemes of CDW were conducted to analyze the environmental benifits: recycling utilization as subgrade materials and directly landfilling. If the subgrade is filled with the recycled CDW aggregates, CDW will be consumed in large quantities and the environmental impactions of eutrophication and ecotoxicity can be reduced obviously.
Junhui Zhang; Le Ding; Feng Li; Junhui Peng. Recycled aggregates from construction and demolition wastes as alternative filling materials for highway subgrades in China. Journal of Cleaner Production 2020, 255, 120223 .
AMA StyleJunhui Zhang, Le Ding, Feng Li, Junhui Peng. Recycled aggregates from construction and demolition wastes as alternative filling materials for highway subgrades in China. Journal of Cleaner Production. 2020; 255 ():120223.
Chicago/Turabian StyleJunhui Zhang; Le Ding; Feng Li; Junhui Peng. 2020. "Recycled aggregates from construction and demolition wastes as alternative filling materials for highway subgrades in China." Journal of Cleaner Production 255, no. : 120223.
This study aimed to develop a finite element model to simulate the flexible pavement structure by considering the nonlinear characteristics of subgrade soils which are related to humidity and stress. First, an analytical model was proposed and proven to quantify the effect of the humidity and stress on the resilient modulus of subgrade soils. Second, a UMAT was programmed to characterize nonlinear moisture and stress-sensitive relationship of subgrade soils. Then, the humidity field values of subgrade were calculated by GEOSTUDIO and verified by field measurement. Meanwhile, the humidity field values were imported into ABAQUS through MATLAB. Finally, the UMAT was implemented in the finite element model of flexible pavement structures. The finite element simulation indicated that the distribution of moisture content of subgrade significantly affects the resilient modulus distribution of subgrade and critical response of pavement structures. Resilient modulus of subgrade soils in the vicinity of load area are significantly larger than those far away the load area. The surface deflection, the tensile stress at the bottom of inorganic binder base, and the compressive strains on the top of subgrade increase greatly with the initial humidity field condition to the equilibrium humidity field condition.
Junhui Peng; Junhui Zhang; Jue Li; Yongsheng Yao; Anshun Zhang. Modeling humidity and stress-dependent subgrade soils in flexible pavements. Computers and Geotechnics 2020, 120, 103413 .
AMA StyleJunhui Peng, Junhui Zhang, Jue Li, Yongsheng Yao, Anshun Zhang. Modeling humidity and stress-dependent subgrade soils in flexible pavements. Computers and Geotechnics. 2020; 120 ():103413.
Chicago/Turabian StyleJunhui Peng; Junhui Zhang; Jue Li; Yongsheng Yao; Anshun Zhang. 2020. "Modeling humidity and stress-dependent subgrade soils in flexible pavements." Computers and Geotechnics 120, no. : 103413.
The use of waste tire rubber as asphalt modifier has been a practice-ready technology. However, the interaction among components within asphalt rubber (AR) and warm asphalt rubber (WAR) is still unclear. During the blending process, the swelling rubber releases polymer agents in asphalt and absorbs components from both asphalt and warm mix asphalt (WMA) additive simultaneously. The component interaction significantly influences the final rheological properties. A comprehensive understanding of the selective absorption of crumb rubber during the blending process provides references to optimize the material and procedure design of rubberized asphalt. To this end, one AR and two WARs were prepared with three mixing durations. The liquid phases and crumb rubber particles were separated. The separated swelling rubber particles were then processed by the staged extraction method to divide the asphalt-rubber interacting area from outside to inside into four layers. The absorption preference of swelling rubber and its influence on rheological properties were investigated by chemical and rheological tests. Test results showed that asphalt fractions with smaller molecular weight were absorbed into deeper layers of swelling rubber. By contrast, crumb rubber was found to be reluctant to absorb the fractions with CO bond during the mixing process. In addition, the Fischer Tropsch (FT) wax showed a negligible influence on the absorption preference, while the effect of surfactant on absorption preference was significant. Finally, the relationship between absorption preference and rheological properties was established. It was found that the absorption preference of crumb rubber is beneficial to the rutting resistance of rubberized asphalt.
Huayang Yu; Zhen Leng; Zeyu Zhang; Danning Li; Junhui Zhang. Selective absorption of swelling rubber in hot and warm asphalt binder fractions. Construction and Building Materials 2019, 238, 117727 .
AMA StyleHuayang Yu, Zhen Leng, Zeyu Zhang, Danning Li, Junhui Zhang. Selective absorption of swelling rubber in hot and warm asphalt binder fractions. Construction and Building Materials. 2019; 238 ():117727.
Chicago/Turabian StyleHuayang Yu; Zhen Leng; Zeyu Zhang; Danning Li; Junhui Zhang. 2019. "Selective absorption of swelling rubber in hot and warm asphalt binder fractions." Construction and Building Materials 238, no. : 117727.
Construction and demolition (C&D) materials obtained from the demolition of buildings are proven to be qualified and sustainable subgrade fillers. The permanent deformation response of subgrade C&D materials under different moisture contents, degrees of compaction, deviator stresses, and confining pressures was revealed by carrying out dynamic triaxial texts. Then, using a four-factor and three-level orthogonal test and by calculating the Gray correlation degree of each factor, the influence degree of each factor on the permanent deformation was determined. The results indicated that two different response types of the permanent deformation of subgrade C&D materials, plastic shakedown and plastic creep, were identified as reason behind the increase in stress levels. Also, according to the Gray correlation analysis results, the permanent deformation of highway subgrade filled with C&D materials is influenced by the deviator stress most significantly, followed by moisture content, degree of compaction, and confining pressure. Finally, a permanent deformation prediction model about this kind of subgrade filler with a reasonable prediction accuracy was proposed.
Junhui Zhang; Anshun Zhang; Jue Li; Feng Li; Junhui Peng. Gray Correlation Analysis and Prediction on Permanent Deformation of Subgrade Filled with Construction and Demolition Materials. Materials 2019, 12, 3035 .
AMA StyleJunhui Zhang, Anshun Zhang, Jue Li, Feng Li, Junhui Peng. Gray Correlation Analysis and Prediction on Permanent Deformation of Subgrade Filled with Construction and Demolition Materials. Materials. 2019; 12 (18):3035.
Chicago/Turabian StyleJunhui Zhang; Anshun Zhang; Jue Li; Feng Li; Junhui Peng. 2019. "Gray Correlation Analysis and Prediction on Permanent Deformation of Subgrade Filled with Construction and Demolition Materials." Materials 12, no. 18: 3035.
The presence of surface cracks has a great influence on the formation of transient saturated zones, which are one of the main factors affecting the stability of colluvial soil slopes during rainfall. This paper aims to examine how the distribution characteristics, such as depth (h), angle (θ), and location of surface cracks, influence the development of transient saturated zones. For this reason, a series of numerical simulations involving colluvial soil slopes is performed. The results show that the development of transient saturated zones in a slope with a crack and that in an intact slope are quite different. In a cracked slope, rainwater infiltrates into the slope along the crack and forms a transient saturated zone at the crack tip. It is found that the smaller the crack depth is, the easier it is for the transient saturated zone at the crack tip to connect with that in the shallow layer, leading to an increase in the area of the transient saturated zone in the shallow layer. Moreover, the larger the crack angle is, the more easily the transient saturated zone at the crack tip connects with both the transient saturated zone in the shallow layer and the groundwater, forming a transient saturated zone that penetrates the entire colluvium. In addition, the lower the location of the crack along the slope surface is, the shorter the time is for the formation of a transient saturated zone at the crack tip, and the larger the area of the transient saturated zone.
Ling Zeng; Liu-Yi Xiao; Jun-Hui Zhang; Qian-Feng Gao. Effect of the characteristics of surface cracks on the transient saturated zones in colluvial soil slopes during rainfall. Bulletin of Engineering Geology and the Environment 2019, 79, 699 -709.
AMA StyleLing Zeng, Liu-Yi Xiao, Jun-Hui Zhang, Qian-Feng Gao. Effect of the characteristics of surface cracks on the transient saturated zones in colluvial soil slopes during rainfall. Bulletin of Engineering Geology and the Environment. 2019; 79 (2):699-709.
Chicago/Turabian StyleLing Zeng; Liu-Yi Xiao; Jun-Hui Zhang; Qian-Feng Gao. 2019. "Effect of the characteristics of surface cracks on the transient saturated zones in colluvial soil slopes during rainfall." Bulletin of Engineering Geology and the Environment 79, no. 2: 699-709.
Weaknesses of the subgrade structure induce the asphalt surface diseases and shorten the service life of flexible pavement. However, the resilient modulus (Mr) of subgrade soils is difficult to be evaluated directly since the subgrade is hidden and covered by the granular or asphalt layer. This study aimed to establish a numerical approach to predict the dynamic behavior of flexible pavements considering the stress sensitivity and moisture variation of subgrade soils. Firstly, 2D FEM simulations of flexible pavements were performed with half-sine loadings. A constitutive model of subgrade soils was proposed to incorporate soil suction and octahedral shear stress. It was validated using the laboratory triaxial test data of 3 selected soils. Then, the developed model was programmed by the user-defined material subroutine (UMAT) in the software ABAQUS. Subsequently, the validity of FEM model was verified by the laboratory tank model. Finally, the effect of moisture contents on the dynamic response of pavement structures was studied by tensile stress and vertical compressive strain. Results show that the surface deflection of the FEM model is similar to that of the actual pavement structure with the R2 of 98.44%. The developed UMAT program is reliable since the distribution of Mr in the FEM model is influenced by the stress and moisture condition of subgrade soils. When the moisture content is increased by 63%, the average Mr of subgrade soils is decreased by 18.7%. Meanwhile, the stiffness softening of subgrade soils increases vertical compressive strain at the top of the subgrade and the tensile stress at the bottom of the surface layer. It is interesting that the developed model can be applied to analyze the fatigue cracking of both subgrade and surface layers in the future.
Jue Li; Jianlong Zheng; Yongsheng Yao; Junhui Zhang; Junhui Peng. Numerical Method of Flexible Pavement considering Moisture and Stress Sensitivity of Subgrade Soils. Advances in Civil Engineering 2019, 2019, 1 -10.
AMA StyleJue Li, Jianlong Zheng, Yongsheng Yao, Junhui Zhang, Junhui Peng. Numerical Method of Flexible Pavement considering Moisture and Stress Sensitivity of Subgrade Soils. Advances in Civil Engineering. 2019; 2019 ():1-10.
Chicago/Turabian StyleJue Li; Jianlong Zheng; Yongsheng Yao; Junhui Zhang; Junhui Peng. 2019. "Numerical Method of Flexible Pavement considering Moisture and Stress Sensitivity of Subgrade Soils." Advances in Civil Engineering 2019, no. : 1-10.
This paper aimed at assessing the feasibility of using the recycled building-related construction and demolition (C&D) wastes in highway embankment. First, the recycling of C&D wastes was elaborated, which involved both the manual and mechanical sorting processes. The recycled C&D wastes were classified as an excellent embankment material according to their gradation and Atterberg limits. The physical and chemical composition of recycled C&D wastes were also investigated, which all met the requirements of DB 41/T 1193 in Chinese Standard. Subsequently, the laboratory triaxial tests were conducted to measure the resilient modulus and permanent deformation of recycled C&D wastes. For comparison, one type of embankment clay soil was also evaluated in this study. The triaxial test results indicated that the recycled C&D wastes exhibited stress-dependent and moisture-sensitive characteristics. The existing resilient modulus and permanent deformation models were found to be capable of accurately predicting these characteristics for recycled material. Compared to the embankment clay soil, the recycled C&D wastes had much higher resilient moduli and lower accumulated permanent deformation. This demonstrated that the substitution of recycled wastes for clay soil would improve the structural capacity and reduce rutting damage. Moreover, compared to the clay soil, the recycled material had less moisture sensitivity to resilient modulus and permanent deformation. This characteristic would be beneficial for use of recycled C&D waste in a hot and humid area. Finally, a field project was constructed on G95 Beijing Capital Area Loop Expressway, which utilized 100% recycled C&D wastes to fill embankment. The embankment application were found to utilize much more recycled materials than other potential applications such as asphalt mixture, cement concrete, and base and subbase. The practices of construction of embankment containing recycled C&D wastes were also elaborated in this study. The lightweight deflectometer was used to measure the in-situ resilient moduli of embankment. The measured results indicated that the recycled C&D wastes had significantly higher structural capacity than the clay soil.
Junhui Zhang; Fan Gu; Yuqing Zhang. Use of building-related construction and demolition wastes in highway embankment: Laboratory and field evaluations. Journal of Cleaner Production 2019, 230, 1051 -1060.
AMA StyleJunhui Zhang, Fan Gu, Yuqing Zhang. Use of building-related construction and demolition wastes in highway embankment: Laboratory and field evaluations. Journal of Cleaner Production. 2019; 230 ():1051-1060.
Chicago/Turabian StyleJunhui Zhang; Fan Gu; Yuqing Zhang. 2019. "Use of building-related construction and demolition wastes in highway embankment: Laboratory and field evaluations." Journal of Cleaner Production 230, no. : 1051-1060.
To investigate the deformation and damping characteristics of cement treated and expanded polystyrene (EPS) beads mixed lightweight soils, this study conducted a series of triaxial shear tests cyclic loading for different confining pressures, cement contents, and soil categories. Through repeated loading and unloading cycles, axial accumulative strain, resilient modulus, and damping ratio versus axial total strain were analyzed and the mechanical behavior was revealed and interpreted. Results show that the resilient modulus increases with increasing confining pressure and cement content. A decreasing power function can be used to fit the relationship between the resilient modulus and the axial total strain. Although sandy lightweight specimens usually own higher resilient modulus than silty clay lightweight specimens do, the opposite was also found when the axial total strain is larger than 8% with 50 kPa confining pressure and 14% cement content. For damping ratio the EPS beads mixed lightweight soil yields a weak growth trend with increasing axial total strain and a small reduction with higher confining pressure and cement content. For more cementations, the damping ratio of the sandy lightweight soil is always smaller than the silty clay lightweight soil. Nonetheless, the differences of damping ratios that were obtained under all of the test conditions are not significant.
Weihua Lu; Linchang Miao; Junhui Zhang; Yongxing Zhang; Jing Li. Characteristics of Deformation and Damping of Cement Treated and Expanded Polystyrene Mixed Lightweight Subgrade Fill under Cyclic Load. Applied Sciences 2019, 9, 167 .
AMA StyleWeihua Lu, Linchang Miao, Junhui Zhang, Yongxing Zhang, Jing Li. Characteristics of Deformation and Damping of Cement Treated and Expanded Polystyrene Mixed Lightweight Subgrade Fill under Cyclic Load. Applied Sciences. 2019; 9 (1):167.
Chicago/Turabian StyleWeihua Lu; Linchang Miao; Junhui Zhang; Yongxing Zhang; Jing Li. 2019. "Characteristics of Deformation and Damping of Cement Treated and Expanded Polystyrene Mixed Lightweight Subgrade Fill under Cyclic Load." Applied Sciences 9, no. 1: 167.
A novel composite membrane blended the sulfonated poly (ether ether ketone) (SPEEK) with modified carbonaceous mudstone (SPEEK/MCM) has been developed for vanadium redox flow battery (VRB). Using a strong acidification treatment, a large amount of hydrophilic oxygen functional groups was introduced on the modified carbonaceous mudstone (MCM) particles, which has been evidenced to enhance the proton conductivity. It is found that the MCM particles help to retard the permeation of vanadium ions through the membrane. With these merits, the VRB single cell based on our novel SPEEK/MCM membrane exhibits outstanding device performance. Notably, the coulombic efficiency (CE) of the cell is as high as more than 99% and the per-cycle capacity loss is only 0.15% under a high current density of 120 mA cm−2. Our work provides a simple method to prepare low cost and high-performance membranes for VRB. More importantly, the SPEEK/MCM membrane has promising potential in other battery applications.
Ling Zeng; Jiaye Ye; Junhui Zhang; Jie Liu; Chuankun Jia. A promising SPEEK/MCM composite membrane for highly efficient vanadium redox flow battery. Surface and Coatings Technology 2018, 358, 167 -172.
AMA StyleLing Zeng, Jiaye Ye, Junhui Zhang, Jie Liu, Chuankun Jia. A promising SPEEK/MCM composite membrane for highly efficient vanadium redox flow battery. Surface and Coatings Technology. 2018; 358 ():167-172.
Chicago/Turabian StyleLing Zeng; Jiaye Ye; Junhui Zhang; Jie Liu; Chuankun Jia. 2018. "A promising SPEEK/MCM composite membrane for highly efficient vanadium redox flow battery." Surface and Coatings Technology 358, no. : 167-172.