Influence Of Polyester Fiber And Salt On Asphalt Mixture Water Stability

The work environment of asphalt pavement is complex. In recent years, water stability of asphalt mixture in conventional region has been studied by the road workers, but in the harsh environment, research is little. So, in this paper through the theoretical analysis and laboratory tests, the freeze-thaw splitting test has been conducted to study the changing rule of water stability of asphalt mixture in different concentrations salt solution and different polyester fiber content, and that provides the basis for improving service performance of asphalt pavement in salt enrichment area.Marshall specimens were made by standard compaction with polyester fiber content0,0.1%,0.2%,0.3%, soaked in different concentrations salt solution (0,8%and16%). Freeze-thaw splitting test was carried out to study change law of asphalt mixture water stability in SYD-0731Asphalt Mixture Uniaxial Compression Apparatus. The results show that:(1) When the concentration of salt solution is same, the splitting tensile strength, freeze-thaw splitting tensile strength and freeze-thaw splitting tensile strength ratio of asphalt mixture firstly increase then descend with the increasing of polyester fiber content, it indicates that water stability of asphalt mixture firstly strengthened then weakened.(2) When the polyester fiber content is same, the concentration of salt solution is higher, the splitting tensile strength, freeze-thaw splitting tensile strength and freeze-thaw splitting tensile strength ratio of asphalt mixture are lower. This shows that salt has greater impact on water stability of asphalt mixture, it reduces water stability of asphalt mixture.(3) Under the effect of sulfate solution, freeze-thaw erosion factor of asphalt mixture firstly upgrade then descend with the increase of polyester fiber content, and freeze-thaw erosion factor of asphalt mixture add polyester fiber is higher than asphalt mixture without adding polyester fiber. It indicates polyester fiber can enhance the ability of the asphalt mixture corrosion.(4) There is an optimal value of polyester fiber content, which is0.2%in this test, and water stability is the best at the same time.(5) The asphalt concrete under different test conditions is tested by ultrasonic. According to the data get regression equation about wave velocity and splitting strength. Splitting strength can be predicted which is without splitting test by using the regression equation, in preparation for the indirect tensile fatigue test.