Performance of Steel Slag as Fine Aggregate in Structural Concrete

Suitability of using steel slag (SS) as substitute for sand in concrete was investigated. SS was collected from a dump site, crushed manually and sieved through between sieves No. 4 and 200. SS was characterized using XRF and XRD techniques. Concrete of mix ratio 1:2:4 was batched by weight with slag replacement levels of 0 to 100% of sand at 25% interval and the concrete specimens (cubes and beams) produced were cured in water for 7, 14, 28 and 56 days. Water demand, compressive strength as well as flexural strength of the concrete were determined. Results indicated that SS contained high amorphous silica (42.40%) and ferric oxides (31.90%) with traces of crystalline particles. The water-cement ratio reduced from 0.62 to 0.50 as slag proportion increased from 0% to 100% at slump range of 6010 mm. The strength of SS concrete increased with increase in proportion of SS. The study suggested that up to 50% of weight of sand could be replaced with slag to produce structural concrete.http://dx.doi.org/10.4314/njt.v34i3.