Optimization And Performance Research Of Low Cost Cement Stabilized Base Material In Highway Pavement

Highway road-bases, as the main load-bearing layer of pavement structure, play a decisive role in the performance of the whole pavement structure. At present, many studies have obtained better road performance, while a large dose of cement has been widely applied to the steady improvement to improve the mechanical properties, but also have a lot of problems. Along with the construction of “Resource-saving and Environment-friendly” putted forward in our country, ensuring the basic performance of pavement highway, and on the basis of the advanced research method of domestic and foreign, low dosage cement and industrial solid wastes used in the road base materials were studied to improve the performance of road base material to a certain extent, and reduce the project cost and environmental pollution. According to the actual engineering application to evaluate its using effect and economic benefit, the main conclusions obtained are as follows:(1)Compaction test results show that based on the same method, with the increase of cement content, optimum moisture content and maximum dry density of cement and fly ash stabilized soil are increased; the optimum moisture content of the cement content of 5% fiber stabilized soil is 17.3%, and the dry density is 1.749g/cm3; with the increase of fly ash content,the optimum moisture content of cement-fly ash stabilized crushed stones increased, the maximum dry density showed a trend of first increase and then decrease.(2) Based on the test result of cement-fly ash stabilized materials, under the same curing condition, with the addition of cement and fly ash, unconfined compressive strength was improved to some extent; with the increase of composite ratio of the desulphurization gypsum and fly ash, compressive strength of cement-fly ash stabilized crushed stones improves, compared with the proportion of 1:1, the compressive strength of 1:2 and 1:3 at7 days increase 5% and 10% respectively. Based on the result of splitting tensile strength, with the addition of fly ash, the splitting tensile strength can increase and be improved obviously.According to the failure mode analysis, fly ash can participate in and promote the pozzolanic effect of adding materials, improving the compactness of whole structure.(3)The test of fiber cement stabilized soil indicates that content and length of fiber have a certain improvement to the strength, also can increase the compressive strength and splitting strength of matrix in a certain range. Comparing with the fiber content of 0‰, 2‰and 4‰, 7d compressive strength of the fiber cement stabilized soil mixing amount of 6‰was better; combined with the failure mode analysis, the polypropylene fiber can significantly improve the performance of stabilized soil.(4)Analysis of the effect of age on the compressive strength of cement stabilized materials found, strength increases rapidly in the early curing age, while the growth rate of the late strength was slow. The comprehensive comparison and analysis of different mixture ratio of modified base material in road engineering and economic effect showed that the addition of fly ash and gypsum, not only makes the strength to meet the needs of practical engineering,but has better economic benefit and environmental protection effect.