Using ground granulated blast-furnace slag and mineral wastes to reduce cement in paving block

Portland cement production releases carbon dioxide; this has significant adverse effects on the environment and so a reduction in the content of Portland cement in concrete products will improve the carbon footprint. This investigation explored the use of by-product materials and waste in the production of paving blocks. The following materials were examined: ground granulated blast-furnace slag, basic oxygen slag, plasterboard gypsum and cement by-pass dust. Ternary blends were created for different mixes and tested. The tensile strength, skid/slip resistance and freeze/thaw of each paving block specimen were determined in accordance with British Standard BS EN 1338. It was found that about 30% cement replacement was achieved in comparison with current factory production in the UK without having any considerable impact on the strength and durability of the paving blocks. It was also found that a cement mix can contain ground granulated blast-furnace slag up to 55%, basic oxygen slag up to 70%, cement by-pass dust up to 10% and plasterboard gypsum up to 5% by weight.