Effects of Different Factors on the Performance of Recycled Aggregate Permeable Pavement Concrete.

Abstract

Urban construction has produced a large amount of construction waste which has caused huge environmental problems. The sponge city is the development direction of urban construction, and permeable pavement concrete is an important material for sponge city construction. To see the law influencing different factors on the performance of recycled aggregate permeable pavement concrete, different water binder ratios, recycled aggregate particle gradations, ordinary aggregate substitution rates, and fly ash and admixture contents are designed to prepare permeable concrete. The compressive strength, permeability coefficient, frost resistance, and pore structure of permeable concrete are tested. The results show that when the replacement rate of recycled aggregate is 50%, the 28-d strength of concrete with a 0.25 water binder ratio can reach 28.9 MPa, and the permeability coefficient is 13.26 mm/s. The addition of fly ash will reduce the compressive strength, and the permeability coefficient increases first and then decreases with the increase of the fly ash content. When the mass fraction of fly ash instead of cement is 12%, the 28-d strength is 94.8% of that of the cement group, and the permeability coefficient can reach 14.03 mm/s. A water-reducing agent can obviously improve the workability of permeable concrete; the best content of the water-reducing agent is 0.2% of the cement mass. A reasonable amount of fly ash and water-reducing agent can optimize the number of harmless holes and less harmful holes in the concrete to improve the frost resistance and strength after the freeze–thaw, and the frost resistance is F150. This study provides a theoretical basis and technical guarantee for the resource utilization of recycled aggregate in permeable pavement concrete.