Experimental Study On Influencing Factors Of Pervious Concrete Based On Orthogonal Method

As a new type of eco-friendly pavement pavement,pervious concrete has been more and more widely used becausue that:it has the advantages of protecting the groundwater resources ? improving the driving environment ?alleviating the city's "heat island effect" and alleviating the problem of urban waterlogging and so on.However,because pervious concrete material contains more pores and larger pore size,when the permeability of pervious concrete is improved,its mechanical properties and durability improved will be affected,and its use in cold areas will also be limited.Therefore,it is great significance for the popularization and application of pervious concrete in the construction of sponge city in cold areas of China to the relationship between the ratio of pervious concrete and the physical?mechanical?durability properties of pervious concrete.In this article,the factors that affect the permeability?compressive strength?frost resistance of pervious concrete are studied,the idea of adding polypropylene fiber to improve the comprehensive performance of pervious concrete is put forward,orthogonal test is used,by changing the ratio of water to cement,the aggregate size of crushed stone and the content of polypropylene fiber to design the mix proportion of pervious concrete,according to the existing pervious concrete pavement construction technology to make test specimen,the coefficient of permeability was measured by the steady water pressure method?gravimetric method for determination of porosity?compressive strength test using SYE-2000 digital pressure tester ? frost resistance was evaluated by rapid freezing method,the influence of various factors on the comprehensive performance of pervious concrete is studied systematically.the main research contents are as follows:(1)The measured porosity,permeability coefficient and compressive strength of pervious concrete were measured according to the corresponding test method.The results were analyzed by orthogonal analysis and variance analysis,and the best matching of each factor with better single physical and mechanical properties is obtained.Through orthogonal analysis point diagram,the influence law of each mix design parameter on the porosity ? permeabilitycoefficient and compressive strength of pervious concrete was analyzed and its influencing mechanism was analyzed.(2)Frost resistance of pervious concrete was tested by fast freezing method,the freezing and thawing temperature range is-16?-6?.The freeze-thaw damage mode and failure mechanism of pervious concrete are analyzed.The orthogonal test and variance analysis were used to analyze the test results,the best combination of the best frost resistance about pervious concrete is obtained.Through orthogonal analysis point diagram,the influence law of each mixture ratio on the freezing and thawing indexes(loss of mass and relative dynamic elastic modulus)were analyzed and the influence mechanism was analyzed.On the basis of considering the relationship between permeability coefficient ? compressive strength and frost resistance of pervious concrete,the design method of mix proportion for North and South China is obtained,it provides the technical basis for the popularization and application of pervious concrete in cold area.