Pavement In China Research Articles

Investigation into Shear Coefficient for Circle Shear Test Method of Asphalt Mixture

In order to efficiently evaluate the shear properties of asphalt mixture, the circle shear test method is proposed. However, the thickness of upper layer surface and the middle-surface of the asphalt pavement in China are usually less than the height of standard specimen in circle shear test, as well as some laboratory specimens. In order to determine the shear strength for samples at different height, the circle shear test is conducted to the specimens at different height, and the height calibration coefficient for non-standard specimens are proposed. With which the shear strength for samples at different height can be unified and easily determined.

Control Research on Construction Excitation Frequency of Resonant Rubblization Machine

Based on the assumption of thin plate of elastic foundation and vibration theory, a method for calculating the fundamental natural frequency of cement slab is presented and the influence of slab dimension and foundation reaction modulus on the fundamental natural frequency of cement slab is discussed. As well, according to the analysis results of fundamental natural frequencies of typical cement pavements of China, the selected proposals of the excitation frequency of the resonant rubblization machine are presented. The research results provide a theory support to popularize resonant rubblization technology in overlaying and rebuilding engineering of the existed cement pavements in China.

Reliability Analysis of Asphalt Pavement Structure Based on Three-Dimensional Finite Element

The design of asphalt pavements in china is currently based on the multilayered elastic method, which is analytical in nature and yields stresses, strains, and deflections in the pavement system for a particular loading condition and pavement geometry, which are compared with established failure criteria to determine the performance of the given pavement. This design approaches is deterministic. In this paper, typical asphalt pavement structure reliability analysis was performed in which factors that affect pavement reliability regarded as input random , pavement surface deflection, layers of bottom stress and limit state function regarded as output variables , by reliability tool infinite element analysis, base on Monte Carlo’s Latin hypercube sampling method.At last the paper pertinently offered decision basis for improve the reliability of pavement structure and important reference values for drafting and selecting of asphalt pavement design parameters through calculating the reliability of pavement structure, sensitivity analysis of the design parameters is made.

Mix Proportion Design Method Optimization of Asphalt Mixture for Heavy Load Pavement

Mix proportion design methods of different asphalt mixtures used in China and other countries were taken comparative analysis. Volume indexes were proposed for gradation design of mineral aggregate and road performance parameters for function analysis in structure layers were used to determine optimum asphalt content in accordance with the service requirements and current construction situation of heavy load asphalt pavement in China, and other performance indexes were taken as verification parameters for mix proportion design of asphalt mixture. Consequently, asphalt mixture with optimized design methods can reflect the actual service condition of heavy load asphalt pavement and correspond with the design and construction of heavy load asphalt pavement in China.

Study on the Reclaimed Binder Properties Using Vacuum Rotating Reclaim

In the past few years, recycled asphalt has been used successfully in asphalt concrete pavement in China. However, the performance of recycled asphalt does not know. The objective this study is analyses the performance of asphalt which using vacuum rotating reclaim. Lanlian No.70 petroleum asphalt was put into pressure aging vessel after one hour, five hours, ten hours, fifteen hours, and twenty hours of aging. Afterwards, the different aging degree asphalt was dissolved by trichloroethylene, and then asphalt reclaimed which using vacuum rotating reclaim method. In the end, performances indexes of recycled asphalt were tested, such as penetration, softening point, ductility, viscosity, dynamic shear modulus, phase angle, bending creep stiffness. Performances indexes of Lanlian No.70 original petroleum asphalt were also tested. The performances indexes were compared of different aging degrees recycled asphalt and origin asphalt. Comparison results indicate that some performance indexes of recycled asphalt are decease; these indexes consist of penetration, ductility and phase angle. The other performances indexes are rise; those indexes include softening point, dynamic shear modulus, bending creep stiffness and viscosity. However, variation of performances indexes is minimal. Therefore, vacuum rotating reclaim method will not make asphalt ageing for considering equipment and human factors. We can use vacuum rotating reclaim method to reclaim discard asphalt concrete.

Studies on Compatibility between Slipform Paving Cement Concrete and Complex Admixtures

The slipform paving technique has been utilized widely in the construction of high-class highway cement concrete pavements in China, resulting in increased use of complex admixtures. Complex admixtures usually contain various components that may have potential compatibility issues, not only between admixtures and cement, but also between admixture components. In order to alleviate or eliminate potential incompatibility problems, it is necessary to adjust the mix proportions and admixture chemical components by taking into account the real-life materials and surrounding conditions. An optimum dosage of the complex admixture should be determined according to the specific job requirements and construction technique. Compatibility issues always arise between admixtures and cements. It was found that Na2 S O4 and Ca Cl2 may increase the early strength, but also may reduce the slump of the mix. When the resin-based air-entraining agent and water reducers were used together, they produced a large amount of resid...

Research on Measurement and Evaluation of Asphalt Pavement Rut Based on Traffic Safety

Rutting is one of the major distresses of highway pavements in China. Presently, rut depth is the only evaluation index for rutting in China and abroad. However, rut depth can't show the entire extent of rutting. In this research, a rut-meter is developed independently, which is used for inspecting rut of several expressway pavements. The results show that the shapes of rut were different, and the shape of rut affects traffic safety. Multi-indexes are adopted, such as rut depth, rut width, maximum possible water catching area, and average rut curvature radius, in order to describe the characteristics of rut and the relation between rut and traffic safety. The study lays a foundation for more rational new rut indexes.