Compressive Strength of Scoria Added Portland Cement Concretes

This paper presents the results of preliminary studies investigating the potential effects of using scoria as supplementary and its amount on compressive strength of concrete. Concrete mixtures containing 5, 10, 20, 30, 40 and 50 % scoria type natural pozzolan by mass of the total cementitious material were prepared. In addition, a conventional portland cement concrete mixture with the same w/cm ratio was prepared as a reference. Preliminary results indicated that the compressive strength of the concrete mixtures with scoria added up to 30% exceeded the strength of the conventional mixture at 3, 7, 28 and 91 days, whereas the compressive strength of the 40 and 50% scoria added concrete mixtures decreased at 3, 7, 28 and 91 days. It was found that early strength of scoria added (up to 30%) concrete mixtures showed higher compressive strengths up to 112%.