Strength, Porosity and Permeability Properties of Porous Concrete Made from Recycled Concrete Aggregates

Due to expansion in infrastructure and increased development of urbanization in Ethiopia, most of the places are covered either by impermeable cement concrete or bitumen that blocks the percolation of water from rainfall. A porous concrete made of zero fine aggregates, creating a pore that permits the concrete to be water permeable, is highly desirable. Similarly, the demand for natural coarse aggregates remains high, while natural resources are being depleted. Therefore, this study aims to investigate the properties of porous concrete using recycled concrete aggregate as a partial replacement for natural coarse aggregate. Experimental tests were conducted on cement setting time, workability of concrete, compressive, split tensile, porosity, and permeability of porous concrete. The properties of porous concrete at different ratios—0, 15, 30, 45 and 60%—revealed that RCA is suitable for use as coarse aggregate. The optimum replacement percentage of recycled aggregate for porous concrete in terms of strength is 30%, with 28th-day compressive strength of 17.37 MPa. However, slight increments were observed in porosity and permeability coefficient. Therefore, the concrete produced in this study is structural concrete, which is suitable for walkways and other concrete flat works, whereby heavy vehicle traffic loads do not exist.