Potential use of high-volume of slag in pervious concrete: technical assessment and sustainability analysis

Large porosity and interconnected pore structure allow pervious concrete to find interesting applications in urban pavement. At the same time, accounting for the exorbitant greenhouse gas emissions associated with Portland cement production, the application of supplementary cementitious materials (SCMs) in pervious concrete has received significant attention in studies. This research investigates the feasibility of developing pervious concrete by substituting a high volume of Portland cement with slag. Different mixtures were made to investigate the effects of high-volume slag content (60% and 80%), fine aggregate incorporation (10% and 15%) and combined use of SCMs (high-volume slag + silica fume) in pervious concrete. Concretes were tested for void content, compressive strength, permeability and abrasion resistance. Based on the results, although the compressive strength of pervious concrete was decreased by the inclusion of high-volume slag, it can be compensated to some extent by increasing the curing age. Furthermore, by decreasing the material cost and CO2 emissions up to 8.2% and 61.2% over plain pervious concrete, respectively, utilisation of high-volume slag can produce relatively more cost-effective and eco-friendly pervious concrete. In general, combined use of slag + silica fume or incorporation of fine aggregate at the optimum replacement ratio can be suggested to obtain higher strength and acceptable permeability in high-volume slag pervious concrete.