SMA路面老化低温力学性能研究

Research of Low Temperature Performance of Asphalt Concrete Under Aging Phenomena

通过老化沥青马蹄脂碎石混合料(SMA-13)的三点弯曲试验,研究了低温对老化SMA-13结构的弯拉强度,弯拉应变及弯曲劲度模量的影响规律。试验结果表明:加载速率相同条件下,-30℃的试件破坏的弯拉强度和弯拉应变小于-10℃的试件的弯拉强度。在加载速率和温度条件相同时,未老化试件破坏的弯拉强度和弯拉应变大于老化后的试件。老化时间越长,高低温度之间的弯拉应变差别越大。在低温条件下,小梁试件的弯拉应变与老化之间有较好的指数变化规律。同时,SMA-13沥青混合料的弯曲劲度模量与老化之间也呈现良好的指数关系。通过对小梁试件破坏前的弯曲应变能的计算,可得知在短期老化附近,SMA-13沥青混合料具有最大的弯曲应变能。

According to three-point bending test, this paper evaluated the influence of low temperature on the flexural strength, the tensile strain and bending stiffness modulus of aged the Stone Mastic Asphalt （SMA） concrete. The asphalt mixtures were aged according to the short-term aging （at 135℃ keeping 4 hours）, and long-term aging （the asphalt con- crete at 85 ℃ keeping 120 hours） and natural aging （3 months, 6 months and 9 months）. The result shows that, with the same loading rate, the flexural strength and tensile strain of specimens under -30 ℃ were smaller than one of those under - 10℃; With the same loading rate and temperature, the flexural strength and tensile strain of specimens without aging were lager than the ones of aged specimens. The longer the aging time, the more the flexural strength differences between high and low temperature. A pretty well index variation can be found between the tensile strain and temperature. The same trend also reveals between the bending stiffness modulus and temperature. By calculating tbe bending strain energy of beam specimens before damaged, it can be obtained that SMA-13 asphalt concrete bad the maximum bending strain energy under - 10℃.