Study On Freezing Resistance Of Basalt Fiber Permeable Concrete

Pervious concrete is a multi-pore structure concrete with coarse aggregate as the skeleton and cementitious materials(usually cement and asphalt)coated with the cementitious material,which has good water permeability.However,the severe cold climate in northeast China limits the popularization and application of pervious concrete.Therefore,in practical engineering application,it is of great significance to study how to improve the frost resistance of pervious concrete in the popularization and application of pervious concrete in severe cold regions.Through investigation and study,it can be seen that the addition of basalt fiber can greatly improve the strength index and frost resistance of pervious concrete.In this paper,the change rule of strength and permeability of pervious concrete with the addition of basalt fiber is studied,and the frost resistance of pervious concrete is further studied.Research methods and main results are as follows:(1)The mixture ratio was designed by volume method,and the preparation technology and preparation process were determined.(2)The influences of fiber diameter,length,content and mixing method on concrete performance were studied.Comprehensive analysis determined that the optimal horizontal combination of each factor was 14 μm in diameter,18 mm in length,2kg/m in content,and the method of cement wrapping stone.(3)The degree of influence of the four factors on porosity is the mixing method > fiber diameter > content > length in order from the largest to the smallest.The optimal levels of the factors are 13 μm diameter,18 mm length,6kg/m content and ready-mixed cement net slurry method respectively.The degree of influence on the permeability coefficient is,in turn,content > length >diameter > mixing method.The optimal levels of factors are 15 μm in diameter,18 mm in length,the content of 2kg/m,and the cementbased method.According to the degree of influence of compressive strength,the four factors were arranged from the largest to the smallest as length > content > diameter > mixing method.The optimal level of factors were respectively 13 μm in diameter,18 mm in length,content 2kg/m,and one-time feeding method.(4)Four groups of tests were set up,namely basic group,fiber group,VAE707 emulsion group and fiber +VAE707 emulsion group,to carry out the freezing-thawing resistance test of pervious concrete,analyze the change of freezing-thawing cycle test index of pervious concrete,and study the freezing-thawing change rule of experimental concrete in the four groups.It is found that adding fiber and VAE707 emulsion can greatly improve the frost resistance performance of concrete.Compared with single silica ash,The Times of frost resistance of pervious concrete with basalt fiber increased by 15-20%,and the times of frost resistance of pervious concrete with VAE707 emulsion increased by 30-40%.