Characteristics of Pervious Concrete with Activated-Sludge Biological Fermentation

Abstract

This study investigates the performance of sludge-added pervious concrete (SPC) at different curing temperatures by replacing some of the cement with activated sludge (AS). The results reveal that the incorporation of AS into pervious concrete had a favorable impact. At a curing temperature of 30 °C, the 28-day compressive strength and specific surface area reached 20.8 MPa and 9.14 m2/g, respectively, representing a 60% and 98.7% increase, in comparison to conventional concrete. Furthermore, the addition of AS to the concrete results in a notable reduction in the concentration of chemical oxygen demand (COD) in surface runoff water. The maximum rate of COD removal observed was 55.6%. A mechanism study revealed that the strength of concrete increased due to the reaction between reactive SiO2 in AS and CaO in the aggregate. At a temperature of 30 °C, the microorganisms in the activated sludge fermentation process exhibit a higher production rate of fermentation gas, resulting in a greater escape of gas and an increase in the number of micropores in the permeable concrete. This leads to an enhanced specific surface area, which in turn exhibits a superior adsorption effect on COD.

Keywords

• activated sludge
• pervious concrete
• curing temperature
• specific surface area
• runoff treatment