Optimization of mechanical properties of pervious recycled concrete using polypropylene fiber and waterborne epoxy resin

Abstract

Although there are many potential applications for pervious concrete (PC) in alleviating urban waterlogging, noise effect, and heat island effect, its porous nature also means that it has a lower strength than conventional concrete. This study strives to improve the mechanical properties of PC considering conventional PC has mechanical flaws. The optimum mix design for PC using recycled coarse aggregate (RCA), fly ash (FA), and polypropylene fiber (PPF) was first researched and selected based on the orthogonal design technique, and the carbon emission from the production end of raw materials was assessed; Second, the influence of waterborne epoxy resin (WER) modification on the permeability and strength of PC was examined. The results of the orthogonal experimental study demonstrated that adding RCA significantly increased the compressive strength of PC while just marginally affecting the permeability indices. To achieve more than 30 MPa compressive strength, the optimum mix design for PC incorporating RCA, FA, and PPF was established (i.e., 15% target porosity, water-binder ratio 0.31, RCA replacement rate 40%, FA content 5%, and PPF volume content 0.11%). The greenhouse gas analysis revealed that this mixture of 50% RCA and 15% FA emits 41.77% less CO2 than the control mix. The use of WER enhanced the mechanical properties of pervious recycled concrete (PRC) by first improving the pore structure at the microscopic level. The findings of the study may serve as a foundation for producing high-performance green PC.