Use of efficiency factors in mix proportioning of fly ash concrete

摘要

In the first revision of IS 10262:2009 an illustrative example of concrete mix proportioning using fly ash has been added. Merely a numerical example without theoretical backup leads to number of queries in the mind of the designer, who has no other option but to follow the steps empirically. To incorporate fly ash in concrete, the total binder content has been increased arbitrarily. This does not seem to be justified as the fly ash used can have a wide variation in properties which have not been taken into consideration. On the other hand if some guidelines are provided on the basis of the efficiency factor of fly ash, at least a good first hand estimate of the fly ash content equivalent to the cement replaced can be obtained. The present paper is a humble effort in this direction.