Papers by Author: Shao Peng Wu

Abstract: This paper focuses on an optimized research about materials and size of electrode of self-monitoring asphalt concrete. It can be easily observed and analyzed the sensitivity of the test and resistivity fluctuations by studying the changes of output resistivity in different electrode embedded in the self-monitoring asphalt concrete. Based on the above method, we can select the proper electrode for the self-monitoring asphalt concrete. The results indicate that the output resistivity of self-monitoring asphalt concrete have much more fluctuation than which used stainless steel mesh as electrode material when choosing the iron mesh as electrode material. Meanwhile, the results demonstrate that the measured output resistivity of self-monitoring asphalt concrete is the most stable when the electrode size is 40~60% of cross-sectional area.

Abstract: This paper investigated the influence of nanoclay on the properties of polymer modified bitumen(PMB). The nanoclay-polymer modified bitumen has been produced by mixing a standard 70/100 pen bitumen with polymer at a fixed proportion and then mixed with different amount of nanoclay. The rheological behaviour of the samples have been determined using dynamic shear rheometer. The morphology of the samples as well as the distribution of polymer and nanoclay throughout the bitumen have been characterized with a fluorescence microscopy. The result indicate that the rheological properties of nanoclay-polymer modified bitumens dependent on the percentage nanoclay. The morphology result shows that dispersed polymer particles existed in continuous bitumen phase and the addition of nanoclay does not seem to change the particle size of the polymer.

Abstract: In this study, residue binders from low penetration grade bitumen emulsions were investigated on the basis of rheology and were compared to the neat bitumen binders of which they were produced. The recovery method proposed by EN 13074 (including both recovery and stabilization process at moderate temperatures) was selected to obtain the residue binders used in the analysis, and the corresponding neat binders were treated the same for comparison. The rheological properties of residue binder from low penetration grade bitumen emulsion were evaluated using Dynamic Shear Rheometer (DSR). During the curing process, three stages were divided, and master curves of complex modulus and phase angle were constructed to allow comparison of the residue binder over a large range of frequencies for each stage. The results showed that the complex modulus increases while the phase angle decreases with curing process for the residues, indicating a better performance in terms of elasticity and stiffness.

Abstract: The key point of preparing conductive asphalt concrete for deicing and snow melting is pavement performance must satisfy the requirements before it can melt snow successfully. This study prefers to prepare electrically conductive asphalt concrete choosing steel slag as the whole aggregates and conductive minerals, while mixed with graphite and carbon fiber. Moisture susceptibility has been evaluated through water-saturated Marshall Stability test and indirect tensile splitting strength test. High temperature performance and fatigue performance were analyzed through dynamic creep test and indirect tensile fatigue test. Results indicate: High temperature performance of steel slag conductive asphalt concrete is better than ordinary basalt asphalt concrete, while its moisture susceptibility and fatigue performance is not good enough and need to be improved.

Abstract: With the widespread application of asphalt mixture, current demand from transportation managers for construction and maintenance of their pavement network consumes large numbers of aggregates. If agencies excessively favor to some certain kinds of excellent aggregates, the cost of construction could be considerably expensive. The major objective of this study is to determine the feasibility of utilizing dacite in asphalt mixtures. By means of Marshall, freeze-thaw, rutting and three-point bending tests, the performances of dacite and basalt asphalt mixture are compared. The results of the testing illustrate that dacite asphalt mixture is more susceptible to gradation and asphalt content than basalt asphalt mixture. Meanwhile it is showed that the performances of dacite asphalt mixture can be improved greatly with the involvement of additives including active mineral powder and cement. Furthermore, it is validated that dacite can be used as alternative aggregate in asphalt mixture.

Abstract: Montmorillonite (MMT), a typical layered silicate, has been widely used to prepare modified asphalt. This paper investigates the high temperature performance and low temperature property on layered silicate modified asphalt concrete. The control concrete is prepared by base asphalt. Meanwhile, three-point bending, conventional and SHRP rutting tests are used to compare the properties of the two types of asphalt concrete. The results of conventional and SHRP rutting tests show that the modified asphalt concrete exhibits a better high temperature performance than the control concrete. And the maximum bending strength of modified asphalt concrete is higher than that of control concrete at the same temperature. It can be concluded that both the high temperature performance and low temperature property of asphalt concrete has been improved efficiently by utilization of layered silicate modified asphalt.

Abstract: This paper investigated the influence of Rediset on the properties of base bitumen. The warm mix bitumen binder were produced by mixing a standard 40/60 pen bitumen with Rediset at fixed two proportions. The dynamic viscosity behaviour of the samples have been determined using dynamic shear rheometer with a cone and a fixed plate with a diameter of 25mm. The thermal stability of the Rediset was characterized and the result indicate that the physicochemical properties of Rediest are stable bellow 150°C. The dynamic viscosity result shows that the addition of Rediset can affect the flow behavior of the bitumen. Rediset decreases the viscosity of the binders, especially at the range of 100°C~150°C. The contribution of Rediset to the change of viscosity became less with the temperature increasing from 100°C to 150°C.

Abstract: To study the possibilities of volatilization in the asphalt pavement during service process, this paper presented an experimental investigation in the laboratory-based environment by simulating the circumstances of Infrared (IR) and Ultraviolet Radiation (UV). The Vacuum (Va) condition was also conducted to discuss the possibilities of volatilization in the asphalts. The changes of asphalt mass, chemical compositions and viscosity were conducted to analyze the experimental results. All the results on the circumstance of Va, that the decrement of asphalt mass, the decrement of light components and the increment of VI values, indicated that there may exist the volatilization in the asphalt. Different trends between IR and UV with asphalts demonstrate that the volatilization is affected by asphalt species and environmental conditions. In addition, ultraviolet radiation may take a vital role on the volatilization of asphalt.

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.

Abstract: Bitumen is widely used in road construction. Due to heavy traffic loads and environmental factors, bitumen properties will change during service life. Bitumen will age due to diffusion of oxygen and UV radiation. Repeated loading will result in decreasing strength because of fatigue. In this paper, one layer clay powder was used to modify base bitumen with different mass contents. Then the influences of ultraviolet radiation (UV) aging on the dynamic fatigue properties of the layered clay powder were evaluated by Dynamic Shear Rheomoter (DSR) and Universal Testing Machine (UTM). The ageing evaluation shows that the ageing resistance of bitumen is improved and this improvement is more notable in bitumen fatigue than mixture.