Study On Pavement Performance Of Recycled Coarse Aggregate Polymer Cement Concrete

There is a lot of waste cement concrete from rebuilding of road and bridge or housing demolition.It will cause serious pollution to the environment by burying simply or scraping waste cement concrete.It is not only complying with development idea of our country,but reducing pollution to the environment and saving a lot of money and labor.Indeed,recycled aggregate concrete has broad prospects for development,and it is also necessary for China’s national conditions.In this paper,the coarse aggregate particle size range is 4.75mm~19.0mm by broking laboratory waste cement concrete to prepare recycled aggregare polymer cement concrete which recycled aggregate replaces natural coarse aggregate at a replacement rate of 40%,and study it’s pavement performance.In this paper,it can get recycled croase aggregate particle by mechanical crushing and arificial broken and wet processing from laboratory waste cement concrete.Then,testing the apparent density,moisture content,water absorption,crushing value,and needle-shaped content of recycled coarse aggregate.Test has shown that the basic performance of recycled croase aggregare is lower than natural croase aggregate which paricle size is same.Test has used the sodium silicate solution and KH-550,KH-560,KH-570 three silane emulsion and polydimethylsiloxane to soak the recycled coarse aggregate,and determined water absorption and crushed value of recycled coarse aggregate after soaking.Test has shown that the crushed value of recycled coarse aggregate is lowest after soaking of 30% sodium silicate solution+30% polydimethylsiloxane,and the water absorption of recycled coarse aggregate is lowest after soaking of 30% sodium silicate solution+30% KH-570 silane mixed emulsion.Taken together,30% polydimethylsiloxane and 30% sodium silicate solution+30% KH-570 silane mixed emulsion have the best effect on the reduction of water absorption and crushed value of recycled coarse aggregate.As a result,they would be used to experiment on the pavement performance test as the optimal conditioning fluid.The recycled coarse aggregate with a replacement rate of 100% was used to design RAC with multiple mix proportion according to different water-cement ratios.At the same time,the recycled coarse aggregate with a replacement rate of 40% was used to design RAC with multiple mix proportion according to different types of polymers.Then,its working performance is studied experimentally and the The reason of the difference is analyzed.Test has shown that the slump value of RAC has been improved remarkably after soaking of 30% sodium silicate solution+30% polydimethylsiloxane,and the working performance is better.The pavement properties of the RAC with recycled coarse aggregate treated with polymer emulsion,refer to compressive strength,flexural strength,tensile strength,dry shrinkage,impermeability and freezing resistance,were studied.Test has shown that the pavement performance of RAC with different water-cement ratio is lower than that of ordinary concrete,and the mechanical strength and durability of RAC have been significantly improved after soaking of 30% polydimethylsiloxane,besides,the durability of RAC has been significantly improved after soaking of 30% sodium silicate solution+30% KH-570 silane mixed emulsion,and the impermeability level was improved to be the same as that of ordinary concrete,but its mechanical strength was lower than that of untreated RAC.Because of pavement performance of the RAC with recycled coarse aggregate treated with high concentration of polydimethylsiloxane emulsion has been significantly improved.In this paper,it is suggested to popularize the method of using high concentration polydimethylsiloxane emulsion to treat recycled coarse aggregate to configure recycled coarse aggregate polymer cement concrete.