Optimum usage of a natural pozzolan for the maximum compressive strength of concrete

Pozzolans provide an economic production possibility in the concrete industry and improve the properties of concrete, such as durability. Effects of a pozzolan on the properties of concrete vary with the pozzolan type and volume. In this study, effect of a natural pozzolan on the properties of concrete was investigated. Fifteen concrete mixtures were produced in three series with control mixes having 300, 350 and 400 kg cement content. These control mixes were modified to have a combination of 250, 300 and 350 kg cement content and 40, 50, 75 and 100 kg pozzolan addition for 1 m(3) concrete. The efficiency of the pozzolan was obtained by using Bolomey and Feret strength equations on 28-day-old concretes. Maximum pozzolan amount with the optimum efficiency was determined. This study shows that the efficiencies obtained from each strength equations are similar and these values decrease with the increase of pozzolan/cement ratio. (C) 2004 Elsevier Ltd. All rights reserved.