Augmentation of Abrams law for fly ash concrete

Abstract

Abrams law which was formulated for conventional concrete containing cement as the only cementitious material, might not be directly applicable for concrete containing present day mineral admixtures. The present study deals with mathematical models using statistical methods relating compressive strength to a number of parameters affecting it, like water binder ratio, fly ash to binder ratio, fly ash content, cement content etc. The importance of the proposed equations has been evaluated by combination of the parameters one by one or by combination with more than one parameter. These models might serve as useful tools in the modification of Abrams law for fly ash concrete. The present research work has been directed towards general concrete construction involving low to medium strengths, no superplasticizer has been used and the mix design methodology has been kept as simple as possible. The water cementitious material ratios ranged from 0.4 to 0.6 and cement was replaced by fly ash @ 0, 20, 30, 40 and 50 percent of the weight of cementitious material. Cementitious material contents ranged between 300 and 450 kg/m3.