半干旱及大温差环境下水泥稳定碎石变形试验

为研究水稳基层变形影响因素，对水泥剂量、品种、级配设计等方面展开系统试验研究。本文对骨架密实型水泥稳定碎石、悬浮密实型水泥稳定碎石和骨架空隙型水泥稳定碎石进行干缩试验及温缩试验，运用Origin对试验数据进行回归拟合，总结半刚性基层材料的变形规律，从而提高沥青路面的耐久性。结果表明：对比结构类型不同的水泥碎石材料可知，骨架空隙型干缩系数0~7 d增大了2倍，后续干缩系数增幅趋于缓和，在水泥用量相同时，骨架空隙型干燥收缩程度最低，即骨架空隙型结构水泥可有效降低水稳基层开裂；水泥稳定砂砾中，随着水泥用量的增加；各个温度段的温缩变形逐渐增大，并且在高温区50~60℃段温缩变形最大，随着温度降低变形量变小，0~10℃段温缩变形最小；同种水泥剂量、水泥标号中，骨架空隙型平均温缩系数最小，悬浮密实型最大，骨架密实型居中。相同级配、相同水泥剂量的水泥稳定砂砾中，42.5水泥试件平均温缩系数大于32.5水泥试件平均温缩系数。

Research on Semi-Rigid Base Materials Under Semi-Arid and Large Temperature Difference Environment

In order to study the influencing factors of the deformation of the water-stable base, a systematic experimental study was carried out on the cement content, variety, and gradation design. The dry shrinkage test and temperature shrinkage test were conducted through skeleton dense cement stabilized crushed stone, suspended dense cement stabilized crushed stone, and skeleton void cement stabilized crushed stone. Using the Origin to perform regression fitting on the test data, the deformation law of the semi-rigid base material was obtained, thereby improving the durability of the asphalt pavement. The results showed that:1) The dry shrinkage coefficient of the skeleton void structure increased by two times in 0-7 days, and the increase of the dry shrinkage coefficient was moderated. The dry shrinkage degree of the skeleton void structure was the lowest at the same cement content, that is, the skeleton void structure cement could effectively reduce the cracking of the water-stabilized base. 2) In cement stabilized gravel, the temperature shrinkage deformation of each temperature section increased gradually with the increase of the cement content, the temperature shrinkage deformation was the largest in the high temperature zone at 50-60℃, and the deformation became smaller as the temperature decreased; In the range of 0-10℃, the temperature shrinkage deformation of the section was the smallest, so the cement stabilized crushed stone is more suitable for the low temperature area in the north. 3) For the same cement content and cement grade, the average temperature shrinkage coefficient of the skeleton void is the smallest, the suspended dense type is the largest, and the skeleton dense type is in the middle. Therefore, the skeleton void structure cement can effectively reduce the cracking of the water-stable base. Through a large number of experimental studies, the skeletal void structure has the best temperature shrinkage resistance, cement 42.5 has better dry shrinkage resistance, and cement 32.5 has better temperature shrinkage resistance.