Experimental Studt On Performance Of Polypropylene Fiber And Basalt Fiber Permeable Concrete

At present,our country is vigorously promoting the construction of sponge cities.Permeable concrete has a high porosity,which is conducive to the infiltration of rainwater on the ground.However,comparing with ordinary concrete,the excessively high porosity of permeable concrete results in lower bearing capacity,cohesive force,frost resistance(under low temperature conditions)and corrosion resistance,which is unfavorable to the engineering application of permeable concrete.In order to solve these problems,this paper chooses basalt fiber and polypropylene fiber to improve the performance of permeable concrete.The content of polypropylene fiber is 3kg/m~3,6kg/m~3,9kg/m~3,and the content of basalt fiber is 2kg/m~3,4kg/m~3,6kg/m~3,8kg/m~3,respectively.The mechanical performance of ordinary and permeable concrete,such as compressive strength,axial compressive strength,flexural strength,water permeability,acid corrosion resistance and low temperature resistance,are studied through experiments.The main research results are given as follows:(1)When the content of polypropylene fiber is 6kg/m~3and the content of basalt fiber is4kg/m~3,the cubic compressive strength and axial compressive strength reach the peak values;when the content of polypropylene fiber is 3kg/m~3and the content of basalt fiber is2kg/m~3,the flexural strength of permeable concrete reaches its peak values.(2)The porosity and water permeability of the two fiber permeable concretes gradually decrease with the increase of fiber content.When the content of polypropylene fiber is kept within 6kg/m~3and the content of basalt fiber is kept within 4kg/m~3,the porosity meets the requirements of relevant specifications.(3)The compressive strength of fiber-permeable concrete shows a trend of increasing first and then decreasing with the increase of acid corrosion time,and reaches the peak value at 20 days.When the corrosion time is 60 days and the content of polypropylene in the permeable concrete is 3kg/m~3and the content of basalt fiber is 6kg/m~3,the corrosion resistance coefficient K is the largest,meaning that the corrosion resistance is the best.(4)When the fiber content is constant,as the temperature decreases,the compressive strength of fiber permeable concrete is constantly increasing.Compared with ordinary permeable concrete,the compressive strength of fiber permeable concrete is obviously improved.If the temperature is set between room temperature(25℃)and-20℃,the compressive strength of permeable concrete is the highest when the content of polypropylene fiber is 6kg/m~3and the content of basalt fiber is 4kg/m~3.