Solid waste management in developing countries: Reusing of steel slag aggregate in eco-friendly interlocking concrete paving blocks production

The needs to meet the global demand for the conservation of non-renewable resources has necessitated the efforts of finding alternative materials. This current study investigates the beneficial utilization of the crushed waste furnace steel slag as a replacement for natural sand in concrete interlocking paving block units’ production for pedestrian and non-traffic applications. A total number of 144 paver samples were cast at replacement percentages of 0, 20, 40, 60, 80 and 100 % by weight of sand using a mix proportion ratio of 1:1.5:3 (cement: sand: granite) at a constant water-cement ratio of 0.5, targeting a strength of 20 MPa at 28 days. Tests carried out include physical characterization of the constituent materials, compressive strength, split tensile strength and water absorption tendency of the hardened H-shaped interlocking pavers. Results showed a significant 15 % increase in the compressive strength at 28-day up to 40 % sand replacement while the tensile strength also increases by 10 % at 28-day up to 20 % sand replacement compared to the control samples before a gradual strength reduction as the percentage replacement increases. The results indicate the possibility of using waste furnace slag for the production of interlocking pavers to promote an eco-friendly and sustainable pavement infrastructure in line with the UN Sustainable Development Goals.