Solidified Water Treatment Sludge as Potential Supplementary Cementious Material in Pervious Concrete Pavers for Mitigating Heat Island Effect

Abstract

Rapid urbanization is increasing impervious surfaces and urban heat. This study explores lightweight pervious concrete pavers with water treatment sludge and/or ceramic dust. Paver mixes were made with different ratios of sludge, where 10% replacement of fine aggregate with ovendried sludge was still structurally sound and practical. While calcined sludge pavers had much higher compressive strength than the other pavers, the oven-dried sludge gave much less energy and cost inputs. Thermal testing of the pervious pavement compared to conventional concrete showed a 6°C drop in bottom-surface temperature at a top temperature of 40°C, though the effect diminished as temperature increased. These results confirm that sludge-based pervious concrete pavers effectively manage heat and retain structural and hydraulic performance for real-world applications and urban infrastructure challenges.