Influence of Water Cement Ratios on the Optimum use of Steel Slag in Concrete

Abstract

In Nigeria and numerous nations of the world, steel is mainly created from purifying of metal scrap and hundreds of tonnes of steel slag are manufactured each year. This study investigated the effect of water-cement ratios (w/c) on the optimum replacement of crushed stone with Prism Nigeria Slag (PNS) in concrete production. PNS were used to substitute crushed stone by 0, 40, 50 and 60%. A mix ratio of 1:2:4 was adopted with w/c of 0.4, 0.5, 0.6 and 0.7. Concrete cubes and cylindrical concrete specimens were cast and cured in water for 7 and 28 days. The behaviour of the hardened concrete shows consistent decreased in compressive and split tensile strengths with increase in w/c. The optimum replacement at 28th days curing for compressive strength was observed at 60% PNS for all w/c. However, the optimum replacement of split tensile strength for w/c of 0.4, 0.6 and 0.7 was found to be 60% PNS while 0.5 w/c had optimum replacement of 40% PNS. The study concluded that 60% PNS with w/c of 0.4 would produce a concrete of high compressive and split tensile strengths than traditional concrete for mix ratio 1:2:4.