Study on the Effect of Fly Ash Admixture on the Performance of Recycled Pervious Concrete

Abstract

In order to solve the problems of recycling of a large amount of coarse aggregate produced after the crushing of waste concrete and urban flooding, this project prepares the recycled coarse aggregate of 4.75-9.5 mm into 100 mm × 100 mm × 100 mm cubic permeable concrete specimens, and researches the influence law of different fly ash admixture on the pore space, water permeability and mechanical properties of the recycled aggregate permeable concrete, and determines the best design The optimal design ratio was determined. The experimental results show that the permeable concrete specimens prepared with recycled coarse aggregate of 4.75-9.5mm particle size and mixed with fly ash were cured in water, and the longer the curing age, the higher the compressive strength. With the increase of fly ash dosage, the compressive strength first rises and then decreases, and the porosity and permeability coefficient decreases continuously. When the fly ash dosage is 15%, the 28d compressive strength of recycled aggregate pervious concrete is the highest, which is 12.8 MPa. At this time, the porosity is 23.9%, and the permeability coefficient reaches 3 mm/s. Considering the overall situation, the optimum dosage of fly ash for recycled aggregate pervious concrete is recommended to be about 15%.