Enhancing runoff treatment using green porous concrete incorporating recycled aggregates

Stormwater runoffs cause adverse impacts on groundwater quality and imperil the sustainable development of human society. Porous pavement can be considered as the first line of defense for contaminant removal from stormwater runoff. The main aim of this study is to produce green porous concrete with improved treatment ability and justified mechanical and hydraulic properties. The physical and mechanical properties, as well as the runoff purification characteristics of environmentally friendly water-permeable concrete using recycled concrete, ceramics, and pumice aggregates, were investigated to present the effective utilization of recycled materials and approach a methodology to enhance the purification of porous concrete. Results demonstrated that the porous concrete incorporating recycled aggregates had promising physical and mechanical properties. Pumice replacement led to an increase in void content, and water adsorption, while a decrease in hardened density was noted. The mechanical properties were adversely affected due to the weak recycled aggregates and aggregate-mortar interface. Moreover, the results demonstrate that the sample containing 25% pumice aggregate had the highest removal efficiency of TSS, TN, NO₃-N, TP, COD, NH₄-N by 77.43, 48.43, 55.26, 85.48, 51.63, 42.22%, respectively. However, 25% replacement of pumice aggregate decreased the compressive strength to 30% compared to the specimen without pumice aggregates. This research presents a novel concrete mix in terms of balancing treatment capacity and mechanical properties. Experimental findings highlight the ability to use porous concrete containing recycled aggregates with enhanced purifying characteristics in pavement applications.