Research On Mechanical Properties And Water Permeability Of Recycled Aggregate Pervious Concrete

With the acceleration of China's infrastructure construction,a large amount of building materials are used.Demolition of old buildings,alterations generated a lot of construction waste.This is reflected in in cities and regions to increase wetland and water area,increased surface infiltration rate of rainwater,and reduction of surface runoff coefficient,effectively reducing the possibility of non-point source pollution and the damage caused by floods and droughts.Therefore,the use of recycled aggregate preparation of pervious concrete has ecological and economic benefits.This article reviews the progress of China's sponge city construction and the status of recycled aggregate production.By using the chemical modification method,fly ash and silica fume were compared to the modification effect of aggregates.Based on the volume method,a new mixing ratio design of recycled aggregate permeable concrete was carried out.It was found that the ratio design with the porosity as an important parameter is more suitable for practical applications.Experiments were conducted on mechanical properties and permeability properties of recycled aggregate permeable concrete.The experimental conclusions are as follows:Three kinds of modification methods can increase the strength of recycled aggregates,and then improve the mechanical properties of concrete.Among them,the modification effect of silicon powder is better than that of fly ash,and the modification effect of water glass and fly ash is the best.Aggregate gradation of the recycled aggregate for formulating permeable concrete is 0-5mm,5-10 mm,10-15 mm,and the proportion is 20%,70%,10%.The mixing ratio design method with the porosity as the main parameter meets the mixing requirements,and the linear relationship between the permeability coefficient and the porosity is more conducive to the application of the actual engineering requirements.The mechanical properties of recycled pervious concrete are greatly affected by the proportion of fine aggregate,but there is an optimal value.