Evaluating the efficiency factor of fly ash for predicting compressive strength of fly ash concrete

Abstract

Fly ash is used as a supplementary cementitious material in concrete. In order to determine the strength of fly ash concrete similar to ordinary Portland cement concrete at a required age, one of the methods of designing concrete mix is by using efficiency factor (k-value) concept. This paper presents the utility of this concept for predicting the strength of fly ash concrete. The 28 days strength-based efficiency factor is 0.54 for 25 % fly ash and 0.35 for 45 % fly ash. The proposed efficiency factor is applicable to wide range of strength and fly ash percentage.