Papers by Author: Ling Pang

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Authors: Shi Lin Yan, Wen Tao Li, Shao Peng Wu, Ling Pang
Abstract: The research on the conductive asphalt concrete(CAC) is to melt snow and ice on the pavement and improve the property of skid resistance. However, research at present mainly focuses on the electrical property not on the fatigue behavior which is also important to the application of CAC in the future. The specific rheological model is developed and the relation between creep and fatigue is investigated in this paper. By the single axial static creep test, the existed rheological model (Burgers model) and method of regression, the creep deformation of asphalt concrete is measured with time and parameters of the model are obtained. The results indicate that strain increases quickly with increasing time at initial loading phase, and then the change of strain tend to a stable value in a constant load. At unloading phase, strain decreases immediately and then keep another stable value which was greater than zero. The addition of conductive fillers improves the elastic properties and has no significant influence to the viscosity of asphalt concrete. In addition, the fatigue life can be predicted by the parameters of the Burgers model. The addition of conductive fillers improves energy dissipated, which leads to shorter fatigue life of conductive asphalt concrete compared to the control at levels of longer fatigue life.
Authors: Xue Mei Zhang, Ling Pang, Shao Peng Wu, Guo Fu Zhang
Abstract: Servicing in the natural environment, asphalt pavement is often exposed to the various aqueous solution, however, the effect of different media aqueous solution on road performance of asphalt mixtures remains ambiguous. In this study, the influences of water, acid, alkali and salt solution on volume of air voids (VV), tensile strength rate (TSR), low temperature performance of 70# asphalt mixtures and SBS modified asphalt mixtures were investigated through freeze-thaw cycles test, void ratio test, Lottman test and Three-point Bending Fracture (TBF) test. The results indicated that freeze–thaw cycles influenced the road performance of asphalt mixtures significantly, increased the air void of asphalt mixtures, and reduced tensile strength ratio and failure strain of asphalt mixtures. Compared with the distilled water, the damage of acid, alkali and salt solution on the road performances of asphalt mixtures were more serious, especially alkali solution to tensile strength rate and failure strains in low temperature, and salt solution to VV. The moisture corrosion resistance of SBS modified asphalt mixtures is better than that of 70# asphalt mixtures.
Authors: Fei Guo, Ling Pang, Zi Qiang Peng, Zu Huang Zhu
Abstract: Rejuvenating seal, widely used due to its economic benefits and convenience, is one of the preventive maintenance methods. The rejuvenating seal materials (RSM) work on the surface course of asphalt pavement. This paper described the effects of RSM on the physical properties and rheological properties of aged SBS modified asphalt (ASMA). Two RSM, R and C, were involved in this research. The dosage of each RSM was 2%, 4%, 6%, 8%, and 10% of ASMA by weight. Physical properties, including softening point, penetration and ductility, were tested. Rheological properties were carried out by means of dynamic shear rheometer (DSR). Results show that RSMs, R and C, have improved the low-temperature performance and fatigue resistance. R has more positive effect on low-temperature performance and fatigue resistance of ASMA compared to values of C.
Authors: Zhang Chao Cui, Ling Pang, Nai Zhi Zhang, Xue Mei Zhang, He Chuan Li
Abstract: Effect of aging on physical properties of asphalt binder was studied. The relationship between degradation of the low temperature properties of asphalt binder and asphalt mixture was also investigated. After the thin film oven test (TFOT) with different aging time, the AH-70 binder and the SBS modified asphalt binder were used to prepared asphalt mixture samples. The binder was characterized using penetration, ductility and Beam Bending Rheometer (BBR), and the low temperature cracking resistance of asphalt mixture was studied by Three-point Bending Fracture (TBF). The correlation between different physical parameters of binder, as well as between different aging properties of the binder and asphalt mixture, was examined. The results showed that aging influenced binder physics significantly, and resulted in a decline in the properties of low temperature cracking resistance of asphalt mixture. Although, aging susceptibility of binder and asphalt mixture may be ranked differently when different evaluation methods ware used, a strong correlation was observed between the aging of binder and asphalt mixture.
Authors: Ling Pang, Lu Long, Shao Peng Wu, Wan Lu
Abstract: Ultraviolet(UV) radiation is one of the main factors induce asphalt aged in the field in-service. Asphalt mortar greatly affects the pavement performance. It is scarce that studies concerning UV aging on the performance of asphalt mortar. In this paper, asphalt mortar with a 1.0 F/A (filler to asphalt)after UV aging were subjected to the test of the Dynamic Shear Rheometer (DSR).Effects of UV aging on the High-Temperature and fatigue performances of asphalt mortar were studied by using the rutting parameter G*/sinδ, fatigue parameter G*sinδ and dynamic viscosity. The results show UV aging had prominent effect on asphalt mortar’s properties, with the decrease of film thickness and increase of UV aging temperature, the ability of rut resistance enhances and fatigue performance weakens.
Authors: Zheng Chen, Shao Peng Wu, Tao Zhang, Ling Pang
Abstract: The major objective of this research was to evaluate the tensile and fracture properties of micro-surfacing, which as a preventive maintenance surface treatment on asphalt pavement, that formed the basis for the ISSA recommendation of an optimum micro-surfacing design incorporating crumb rubber. The research involved a full-factorial experiment with different rubber contents (0, 2 and 5%) and different polymer modified asphalt emulsion contents ranged from 10 to 13% by total weight of crushed aggregate in micro-surfacing. Fracture and indirect tension tests were performed on micro-surfacing beams and Marshall test samples, respectively, at two different test temperatures of 25 and -10°C. The variables studied were indirect tensile strength, peak center-point load carried, and load-point displacement. The results show that higher mean values of indirect tensile strength were obtained corresponding to the highest modified asphalt emulsion content (13%), irrespective of rubber contents, particularly at lower temperatures. A statistical analysis of the test results reveals that there are no significant differences among the means of most of the variables studied corresponding to different rubber contents. However, the differences are significant for different asphalt emulsion contents.
Authors: Hong Hua Zhang, Shao Peng Wu, Ling Pang, Kim Jenkins, Man Yu, Pei Qiang Cui
Abstract: Light components in the asphalt can volatilize under the circumstances of high temperature or long-term service process, leading to the deteriorating of the asphalt pavement. This paper tried to discuss the influences of volatile organic compounds (VOC) emission from the asphalt on physical properties in the high temperature (at 180) by grey system theory. Both Heat and Vacuum environment were monitored as the emission conditions and the emission temperature was 180°C, physical properties of asphalt, released and unreleased were analyzed. Basic tests, including mass change, chemical compositions, penetration and soften point, were used to compare the influences of VOC emission on the asphalts performances. Meanwhile, grey system theory was used to investigate the sequent performances influenced by VOC emission. Results show that physical properties and four generic components of the asphalts are affected obviously in these two emission conditions, and the oxygen may promote VOC emission from the asphalt. In additional, the greatest factor associating with VOC emission is light components in the asphalt.
Authors: Peng Wang, Pei Da Guo, Pan Pan, Ling Pang, Shao Peng Wu
Abstract: Three types of rejuvenator sealer materials were added into asphalt mortar after thin-film oven test (TFOT) and pressure aging vessel (PAV) aging processes. The performances of both aged mortar and rejuvenator treated mortar were evaluated by means of softening point, temperature sweep tests. Experimental results showed that all of rejuvenator sealer materials can significantly increase phase angle and decrease the softening point and complex modulus of TFOT aged asphalt, which means aged asphalt can be efficiently softened with the rejuvenator materials. However, the influence on PAV aged asphalt was slightly in the same concentration, which has a significantly direction for the pavement preservation.
Authors: Shao Peng Wu, Guo Jun Zhu, Ling Pang, Cong Hui Liu
Abstract: According to three-point bending test, this paper explores the influence of low temperature on the flexural strength, the tensile strain and bending stiffness modulus of the aged Stone Mastic Asphalt (SMA-13) concrete. The asphalt mixtures are aged according to the short-term aging (at 135°C, 4 hours), and long-term aging (asphalt concrete at 85°C, 120 hours) and natural aging (3 months, 6 months and 9 months). The result shows that, with the same loading rate, the tensile strain of specimens at -30°C are smaller than those at -10°C; but when temperature is certain, the tensile strain of specimens lager than those of aged specimens. The longer the aging time lasts, the more flexural strength differences between high and low temperatures can be found. A pretty well index variation can be found between the tensile strain and temperature. The same trend also appears between the bending stiffness modulus and temperature of SMA-13 asphalt concrete.
Authors: Ling Pang, Shao Peng Wu, Jun Xie, De Ming Hu
Abstract: The use of gneiss as aggregates might help meet the pavement constructing demands. However, the study of the pavement performances of gneiss asphalt mixture is few. In this paper, the microstructure of gneiss aggregate was studied by Scanning Electron Microscopy (SEM). And the pavement performances of gneiss asphalt mixture with different improving measure were characterized by means of Indirect Tensile Strength Test and Four-Point Bending Fatigue Test. Gneiss is flaky, surface texture rougher and imporosity characteristic in microstructure, resulting to its adhesion and processing property are poor. Experiment results indicate that the use of hydrated lime replacing limestone power partly in filler can improve pavement properties of the gneiss asphalt mixtures distinctly.
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