Experimental Study On Permeability Of Recycled Pervious Concrete

Recycled water permeable concrete is a kind of environment-friendly,timber type building material,with continuous pore concrete,not only has a certain strength,but also has good permeability and permeability.In order to study the strength and pervious performance of recycled water permeable concrete,based on the basic characteristics of test raw materials,four kinds of influence factors were designed to prepare recycled pervious concrete with water cement ratio,reclaimed aggregate substitution rate,regenerated aggregate content and aggregate gradation as the change parameters.The compressive strength,splitting tensile strength and effective hole of the 28 d curing age of regenerated concrete test specimens were passed through test regenerated pervious concrete.The performance indexes such as clearance rate,water permeability coefficient,capillary water absorption and so on,and the correlation relationship between them are analyzed by regression method,which provides a theoretical basis for the innovative development and application of recycled pervious concrete in the ecological water conservancy project.Through tests,the strength and permeability of recycled pervious concrete are satisfied.The compressive strength ranges from 5.18 MPa to 10.7 MPa,and the splitting tensile strength increases with the increase of compressive strength,and the tensile ratio ranges from 17% to 28%,indicating that the brittleness is reduced and the toughness is increased.The strength of the recycled aggregate is increased by adding recycled aggregate in the permeable concrete,and the optimum content of the regenerated micro powder in reclaimed water permeable concrete is 15%,and the strength decreases rapidly when it is over 15%.In the water permeability,the porosity ranges from 17.68% to 26.78%,the permeability coefficient ranges from 3.28 to 4.5 mm/s,and the porosity and compressive strength show a downward trend,which have a positive correlation with the permeability coefficient.The effective porosity is the main factor determining the pervious performance of recycled pervious concrete,and the permeability coefficient can be increased from 8% to 28% by two particle size.By observing the cross section image of the specimen,the size distribution of the cross section of the double particle size specimen is not uniform,and the whole distribution is in the normal distribution.The plane porosity,the number of pores and the cross section pore area are increased with the increase of the recycled aggregate(fine grade material)of 4.75 to 9.5 mm,and the number and area of the cross section pores are permeable to the regenerated permeable concrete.Water capacity plays a key role.As far as water permeability is concerned,the water permeability coefficient of RPC can be improved by adding 4.75~9.5 mm recycled aggregate(fine grade material),and the two grain grade RPC,which is mixed with 2:1,can ensure good permeability on the basis of higher strength.Through the study and calculation of the phenomenon of capillary water absorption of recycled pervious concrete,it is concluded that the water absorption process of the specimen shows a power function distribution,the water absorption speed in the early stage is faster,and the curve tends to be slow in the later stage,and the rising amplitude decreases.Finally,the main contents and test results of the research are summarized through experiments,and the application prospect of construction waste and recycled permeable concrete is prospected.