In order to evaluate the performance of the physical foaming warm-mix recycled asphalt mixture (WRAM), the hot mix plant recycling technology was adopted to develop AC-20 hot-mix recycled asphalt mixture (HRAM) and the WRAM of different reclaimed asphalt pavement (RAP) contents. The high temperature stability, water stability and low temperature crack resistance performance of the reclaimed asphalt pavement were evaluated. The results indicate that the physical foaming WRAM feature better high temperature stability, water stability and low temperature crack resistance compared to those of HRAM. With the increase in RAP contents, the high temperature stability of the physical foaming WRAM and HRAM rises notably but the water stability and low temperature crack resistance performance continues to drop.
This paper mainly used the Superpave and the Marshall design methods to design the mix ratio of the hot mix plant recycled asphalt mixture. The road performance of AC-20, SUP-20 with 30% RAP content and AC-20 with 50% RAP content was studied to evaluate the water stability and high temperature stability and low temperature crack resistance of the recycled asphalt mixture. Research shows that the road performance of AC-20 mixed with 50% RAP content meets the technical requirements of the same type of asphalt mixture. It is recommended to use the Marshall design method for hot mix plant recycled asphalt mixture design.
The dynamic triaxial test is carried out by the dynamic cyclic shear equipment GDS to determine the strength of soil after earthquake cyclic loading. The consolidation pressure is determined according to the in-situ stress state of soil samples. The samples are loaded with sinusoidal periodic loads of different amplitudes at a fixed frequency, with the failure standard of achieving the same final residual strain. Compared with the static triaxial test results, we can determine the strength weakening of soft clay foundation with different depths under earthquake load, which can provide a reliable reference for engineering problems such as the bearing capacity of pile foundation in soft clay.
In order to improve the strength of cement concrete pavement and reduce pavement cracking, the application effect of the hydration reaction enhancer Mixconverter in cement concrete pavement was studied by testing the compressive strength, bending strength, crack resistance and chloride ion permeability of concrete indoors. The test results show that the addition of Mixconverter to concrete can significantly improve the compressive and flexural strength of concrete, effectively prevent the expansion of plastic shrinkage and cracking of concrete, and significantly reduce the chloride ion diffusion coefficient. Finally, the test road pavement further proves the improvement effect of Mixconverter on concrete strength and cracking.
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