关键词: 道路工程；拱胀变形；室内模拟；水泥稳定基层；SEM；CT

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