新疆硫酸盐渍土地区沥青路面鼓胀变形机理研究

Bulging deformation mechanism of asphalt pavement in sulfate saline soil areas of Xinjiang

依托新疆阿克苏地区的两条公路,在进行公路路面鼓胀病害调查的基础上,选择4个典型病害部位开挖试坑,观察了路面结构层中损坏的情况,同时取样测试了基层及路基填料的含盐量、矿物成分、pH值等,分析了两条公路路面鼓胀病害的产生机理。研究结果表明:公路A(省道)路面基层中的离子以SO_(4)^(2-)、Ca^(2+)为主,因此发生了钙矾石型硫酸盐侵蚀。公路B(国道)路面基层中Ca^(2+)含量较高,同时含有一定量SO_(4)^(2-)和CO_(3)^(2-),因此发生了硅灰石膏型硫酸盐侵蚀。此外,夏季高温条件、水泥中碱含量超标等都加剧了两种硫酸盐侵蚀的发生。最后,根据两条公路病害产生机理,提出了硫酸盐渍土地区路面鼓胀病害的预防措施。

Based on two highways in Aksu prefecture of Xinjiang, four typical diseased sections are selected to excavate test pits on the basis of investigating bulging diseases of highways, the damage of structure layer pavement is observed, the salt content, mineral composition and pH value of base and subgrade fill are sampled and tested, and the mechanism of pavement diseases of the two highways is analyzed. The results show that the ions in the base course of Highway A(Provincial Highway) are mainly SO_(4)^(2-) and Ca^(2+), so a chemical reaction takes place and Ettringite is formed. The content of Ca^(2+) in the base course of Highway B(National Highway) is high, and it also contains a certain amount of SO_(4)^(2-)and CO_(3)^(2-), so a chemical reaction takes place and Wollastonite gypsum is formed. In addition, the high temperature in summer and the alkali content in cement exceed the standard, accelerate the occurrence of two kinds of sulfate erosion. Finally, according to the mechanism of the two highway diseases, the preventive measures for bulging diseases of highways in the sulfate saline soil areas are put forward.