Experimental Study On Anti Erosion Measures Of Cement Stabilized Macadam Base In Sulfate Environment

Sulphate erosion of cement stabilized material base to produce ettringite,thaumasite or other expansive substances and cause road base expansion is very common throughout the country and the world.In the context of accelerating the implementation of strategic national policies such as the Belt and Road Initiative,the reconstruction and expansion of new highways and existing highways in Xinjiang will be widely carried out,and will inevitably cross the saline soil area.The research on anti-sulfate erosion measures of cement stabilized macadam base is an urgent problem to be solved in the development of highway construction and transportation industry in the region.In this paper,according to the swelling disease of sulfate eroded base course in Xinjiang Tumushuke Yijianfang second-class highway and other road projects,through indoor sulfate erosion resistance test,the appearance changes of specimens after different drying and wetting cycles were observed,and the quality,strength and p H value of specimens were tested,The influence of different initial salt content on the sulfate resistance of ordinary portland cement stabilized base was studied,and the sulfate resistance effect of some improvement measures such as adding a certain amount of fly ash and using high belite sulphoaluminate cement instead of ordinary portland cement was studied.The main conclusions are as follows:(1)Under the combined action of long-term dry and wet cycle and sulfate erosion,when the sulfur content of ordinary portland cement sample reaches 3600 ppm,the strength damage will occur due to sulfate erosion after 63 dry wet cycle tests.When the content of sulfur in cement fly ash stabilized macadam and high belite sulphoaluminate cement stabilized macadam reaches 4900 ppm and 17600 ppm respectively,the structure integrity and strength can be kept up to the working requirements after 63 dry and wet cycle tests.(2)Under the same initial salt content and environmental conditions,compared with ordinary portland cement,the improved method of cement fly ash stabilized material can delay the occurrence of erosion and expansion failure.Under the same mixing water and environmental conditions,the sulfate resistance of high belite sulphoaluminate cement stabilized macadam is better than that of cement fly ash stabilized macadam and ordinary portland cement stabilized macadam.(3)When the initial salt content is too high,the high belite sulphoaluminate cement stabilized macadam is also difficult to resist the ultimate erosion and expansion failure.