Mix proportioning of fly ash concrete: comparison of salient codes

Abstract

A comparison of three procedures, namely IS 10262:2009, ACI 211.1-91 (Reapproved 2009) and DOE 1997, for mix proportioning of fly ash concrete, is presented. A procedure is proposed for mix proportioning of fly ash concrete, which is an improvement over DOE method and takes into consideration the variation in cementing efficiency factor with fly ash percentage and age of concrete. Based on review of relevant literature, guidelines are provided for determining the fly ash cementing efficiency factor considering percentage of fly ash and age of concrete. It is noted that fly ash cementing efficiency factors available in literature can be used for mix proportioning of concrete having fly ash content ranging from 15% to 75% of cementitious material. Recommendation to IS 10262:2009, which will help in optimizing the number of trial mixes and in increasing the range of applicability to higher percentages of fly ash, is presented.