Optimum Fly Ash Content for lower Cost and Superior Durability

Abstract

Superior durability of fly ash concretes have been very well established by many research works throughout the world. However, the decision to use the fly ash concrete or not and also the fly ash content in the concrete is based on the cost of the concrete in most of the cases, if not all. Thus a methodology has been developed to estimate the optimum fly ash content for the lowest cost and maximum durability of the concrete. Concretes of different fly ash content were prepared and their costs were calculated. Durability properties of some of the concrete were determined by experimental measurement of their relative service life. The type of environment was also considered. Optimum fly ash content was determined based on cost, durability of the concrete, and the type of environment. The price structure of concrete-making materials in Australia was used as an example in the calculation of optimum fly ash content for the lowest price. It is expected that the price structure found in other countries would be different and accordingly the optimum fly ash content will also be different. However the methodology has been presented and this methodology can be used to calculate the optimum fly ash content for any price structure. This methodology provides scientific way of estimating the fly ash content which would give the lowest cost for an environment.