Work

Short-term bioclogging and recovery characteristics of pervious concrete

Year: 2025

Type: article

Abstract: Similar to soil layers for filtration systems and water recharge, pervious concrete would become clogged over time by microbial action in rainwater infiltration and humid environments . Bioclogging in pervious concrete in practice could be induced by a variety of bacteria, but has received little attention and limited investigation. In this study, Pseudomonas aeruginosa ( P. aeruginosa ) was utilized as a model organism to perform 30-day short-term bioclogging experiments. Bacterial activity , surface biofilm growth, porosity, and permeability coefficients were measured to investigate bioclogging characteristics, followed by bioclogging recovery performances under physical pressure washing and chemical silver hydrogen peroxide (SHP) solution. It was determined that the P. aeruginosa bacterial activity at 35 °C reached the exponential growth phase in 3–5 days, achieving a maximum OD600 value approximately double that observed at 10 °C. Because of differences in bacterial activity, surface biofilms formed from the three nutrient supplies at 35 °C displayed almost complete coverage in 9–12 days, while even the highest nutrient supply (20 mmol/L) achieved only 92 % coverage over 30 days at 10 °C. Rapid biofilm accumulation at 35 °C over 30 days resulted in a 1.4–2.2-fold reduction in cumulative porosity compared to 10 °C. The permeable properties of biofilms, in addition to the unique pore structure characteristics of pervious concrete, contributed to only a moderate reduction in permeability caused by short-term biofilm accumulation. The regional porosity measurements reflected that biofilms could induce spatially nonuniform bioclogging that decreases from top to bottom. It was found that more than 65 % of the total biofilm accumulation occurred in the 0–60 mm regions, and the uppermost 0–20 mm layer was identified as the most critical clogging location due to low porosity and significant biofilm accumulation. Although effective in the 0–40 mm regions, pressure washing for 15–20 s was ineffective deeper down while leading to secondary clogging. In contrast, SHP cleaning was found to remove more than 80 % of biofilms in all regions from top to bottom, resulting in an almost complete recovery of both regional porosity and permeability.

Source: Construction and Building Materials

DOI: 10.1016/j.conbuildmat.2025.141186