Mix Proportion Design And Road Use Of Porous Cement Stabilized Macadam Performance Test Research

When the water can not be discharged in time when it seeps into the pavement,water damage will occur on both asphalt concrete pavement and cement concrete pavement,which may cause serious damage to the pavement structure.The use of porous gravel base structure is one of the effective measures to reduce the water damage of pavement structure.The main contents of this paper are as follows:(1)raw material selection and test.(2)The design of the mixture ratio of porous cement stabilized macadam was carried out to explore the reasonable forming mode,appropriate water cement ratio and mineral aggregate gradation of the porous cement stabilized macadam.(3)The fluidity test of cement mortar was carried out to determine the change rule of water cement ratio of cement mortar after adding the admixture.(4)The road performance of porous cement stabilized macadam base,the strength characteristics and drainage performance of porous cement stabilized macadam specimens with different admixtures(fly ash,silica fume,mineral powder).The main conclusions of this paper are as follows:(1)in this experiment,single aggregate grading and double aggregate grading are selected.According to the vibration test,the volume ratio of the two aggregates is 7:3.When the water cement ratio and the cement content are the same,the void ratio of the two aggregates is less than that of the single aggregate,and the compressive strength of the Porous Cement Macadam with the two aggregates is more.(2)According to the crushing degree of the mixture after compaction and the dense state after compaction,the reasonable number of compaction is 10 times.It is feasible to form porous Cement Macadam by static pressure method.(3)According to the strength,porosity and the state of cement paste,the range of water cement ratio is 0.35-0.45.(4)According to the fluidity test of mortar,the suitable water cement ratio of Porous Cement Macadam after adding the admixture can be determined.After adding silica fume,the cement ratio should be increased(0.43-0.57),and the water cement ratio slightly decreased(0.38-0.40).When adding fly ash,the water cement ratio should be smaller(0.34-0.40).(5)The strength of Porous Cement Macadam can be improved by appropriate amount of mineral powder and fly ash,and the strength of fly ash can be improved in a long age.With the addition of silica fume,the strength of Porous Cement Macadam decreases,which is related to the fine particle size,porous and high water cement ratio of silica fume.(6)In practical application,thetype and amount of admixture should be considered reasonably according to the strength requirements of the base course,the law of the influence of admixture on the strength of Porous Cement Macadam and the principle of economy.The reasonable amount of admixture is between 10% and 20%.The research results of this paper can provide some technical guidance for the popularization and application of porous cement stabilized macadam base.