Abstract: In order to explore the factors influencing the arch expansion of asphalt pavement of cement stabilized base in large temperature difference desert area, based on south Xinjiang climate temperature difference and cement stabilized gravel component materials, an arch expansion test of cement stabilized base material was conducted. The arching deformation of water stabilized gravel specimens with different gradation types, different cement dosage, different sulfate content and different environmental humidity was simulated. The arch expansion performance and change law of cement stabilized base material under different factors were clarified, and the reasonable range of each design index was given. Moreover, combined with modern electron microscope scanning technology and industrial CT, and the development mechanism of internal arching of water stabilized gravel material was further revealed. The research results show that, under different temperatures, the expansion coefficient of water-stabilized sand and gravel material with skeleton void structure is the smallest, followed by that of skeleton dense structure, and the expansion coefficient and expansion amount of the specimen formed by suspended dense structure are the largest. The increase of cement dose is positively correlated with the expansion amount of water-stabilized sand and gravel mixture. In the process of heating up, low salt content and environmental humidity have no significant effect on the expansion amount of the specimen. When the sulfate content reaches 0.8%, the salt swelling effect is initially reflected. In the temperature range of 30~40 ℃, the arch expansion reaction of the specimen is the most severe. It is suggested to adopt skeleton pore gradation structure in desert area with large temperature difference and the appropriate cement dose is 4%.

Key words: highway engineering; arch expansion; indoor simulation; cement stabilized base; SEM; CT

摘要： 为探究大温差荒漠区水泥稳定基层沥青路面拱胀变形影响因素，基于新疆南疆地区气候温差及水泥稳定砂砾组成材料，进行了水泥稳定基层材料拱胀试验，模拟了不同级配类型、不同水泥剂量、不同硫酸盐含量和不同环境湿度下水稳砂砾试件拱胀变形，明确了不同因素下水泥稳定基层材料拱胀性能及变化规律，给出了各设计指标合理范围，并结合SEM及工业CT进一步揭示了水稳砂砾材料内部拱胀发展机理。研究结果表明：不同温度下，骨架空隙结构的水稳砂砾材料膨胀系数最小，骨架密实次之，悬浮密实结构试件膨胀系数及膨胀量最大；水泥剂量的提高与水稳砂砾混合料膨胀量呈正相关；在升温过程中，低含盐量及环境湿度对试件拱胀量没有显著影响，硫酸盐含量达到0.8%时，盐胀作用才初步体现；30~40 ℃这一温度区间试件拱胀反应最剧烈；建议大温差荒漠区采用骨架孔隙级配结构，水泥剂量4%为宜。

关键词: 道路工程；拱胀变形；室内模拟；水泥稳定基层；SEM；CT