Mechanical and Hygrothermal Properties of Zeolite-Modified Pervious Concrete in Hot and Humid Area

Abstract

Pervious concrete has good permeability and moisture adjustment properties due to its rich pore structure. It can not only reduce surface runoff by infiltration of rainfall, but also retain a certain amount of water inside, and then decrease the surface temperature via evaporation. In order to optimize the evaporative cooling performance of pervious concrete, this study introduces a modified method of incorporating superabsorbent zeolite produced from industrial wastes into pervious concrete as hygroscopic filler. The effects of zeolite dosages on the basic physical and mechanical properties of pervious concrete were analyzed, and then the evaporative cooling performance of zeolite-modified pervious concrete with the optimum replacement rate was studied. The results showed that the zeolite addition significantly reduced the density of pervious concrete, while having little impact on the permeability. The compressive and splitting tensile strength of pervious concrete increased first and then decreased as the replacement rate of zeolite powder increased, and the content of 15% zeolite powder and 20% zeolite aggregate was beneficial to improve the mechanical properties of pervious concrete. Contributing to the abundant micro-pores and higher specific surface area of zeolite particles, this could improve capillary water absorption and the water storage ability of pervious concrete. During the process of evaporation, the water absorption increment could effectively reduce the surface temperature by 5–8 °C, and maintain the evaporation cooling effect for 10–12 h.