拉萨地区不同空隙率的半柔性路面材料冻融试验研究

为解决现有水泥混凝土和沥青混凝土路面材料在拉萨地区推广应用中受冻融作用破坏的问 题，对不同空隙率的半柔性路面材料在拉萨的应用进行研究。采用灌注式的方式将水泥胶浆灌入 不同空隙率的开级配沥青混合料母体中制成试件，并根据拉萨独特的气候特征设定冻融试验的时 间和温度；再进行高温稳定试验和低温抗裂试验，得出趋近于真实冻融环境的试验数据。分析试 验数据可得，半柔性路面材料在受到冻融作用破坏时，低温抗裂强度随着空隙率的增大呈逐渐上 升趋势，劈裂位移量随着空隙率的增大呈逐渐减小趋势；而表征高温稳定性能的动稳定度随着空 隙率的增大呈先上升后下降的趋势，变形速率随着空隙率的增大呈先下降后上升的趋势。研究结 果表明，半柔性路面材料采用27%的空隙率并添加塑弹性材料有利于抵抗冻融破坏，从而能够在 高原地区推广和应用。

Freezing-Thawing Test Research of Semi-Flexible Pavement Materials with Different Void Fraction in Lhasa

In order to solve the problem that the cement concrete and asphalt concrete pavement material were damaged by freezing-thawing action during their popularization and application in Lhasa, a research about the application of semi-flexible pavement materials with different void fraction in Lhasa was carried out. Test specimens were made by the way of pouring cement mortar into open-graded asphalt mixture matrix with different void fraction. The time and temperature of freezing-thawing test were set based on the special environment of Lhasa. Then the high-temperature stability test and low-temperature crack resistance test were carried out to obtain the test data closing to the real environment. By analyzing the test data, it was educed that: when semi-flexible pavement material was destroyed by freezing-thawing action, with the increasing of void fraction, the low-temperature crack resistance increased gradually, and the split displacement decreased gradually; meanwhile, the dynamic stability characterizing high temperature stability presented a trend that it increased first and then decreased with the increasing of void fraction, and the rate of deformation presented a trend that it decreased first and then increased. The results show that the semi-flexible pavement material with 27% void fraction and addition of elastic plastic material is beneficial for resisting the freezing-thawing damage, after that it can be generalized and applied in plateau region.