Threshold value of water stability evaluation index of asphalt mixture under multi-temperature conditions
To prevent and reduce the moisture damage of asphalt pavement,based on the surface energy theory and the monthly average temperature of major cities in six regions of China,two evaluation methods,including surface energy test and macroscopic moisture stability test,were combined to accurately evaluate the water stability of asphalt mixture under multi-temperature conditions.First,the surface energy of raw materials was tested in the temperature range of-20 to 50℃to determine the value of adhesive evaluation index ER(Energy Ratio)at various temperatures.Four types of asphalt mixtures were selected for five freeze-thaw cycles splitting tests at-20℃,immersion Marshall tests at 10℃and 30℃,and immersion Hamburg rut tests at 50℃.According to the test indexes determined by the above three macroscopic tests and their corresponding technical requirements,the threshold values of ER corresponding to each temperature were determined.The experimental results show that the threshold values of ER of the asphalt mixture without modifiers at-20,10,30,50℃are 0.992,1.693,0.994 and 0.512,respectively.The threshold values of ER of modified asphalt mixture are 1.562,1.944,1.144 and 0.512,respectively.Furthermore,based on the threshold values of asphalt mixture water stability evaluation index under multi-temperature conditions,the relationship model between threshold value of asphalt mixture without modifiers and temperature was established as y=-0.000 6x2+0.009 7x+1.472 6,and the relationship model between threshold value of modified asphalt mixture and temperature is y=-0.000 6x2+0.000 4x+1.834 1,in which the x indicates temperature and y indicates the corresponding threshold value.
万方数据
维普
