Use of coal fly ash in concrete mix

In the past, fly ash produced from coal combustion was simply entrained in flue gases and dispersed into the atmosphere. However, during past few years, the need of environmentally friendly disposal method of coal fly ash has increased due to serious environmental and health concerns. A number of studies have been reported on the use of fly ash both in production of cement and in concrete mix. This is mainly because of many advantages such as reduction of the amount of carbon dioxide into the atmosphere during the production of cement and being able to recycle the fly ash. This paper presents the preliminary results of a project at Central Queensland University to investigate the optimum amount of coal fly ash that can be used as a replacement for cement in concrete mix for non-structural construction such as landscape materials or domestic foot path. Coal fly ash obtained from a local power station was used in the concrete mixes. Varying amount of fly ash was used to replace the fine aggregate and, initially,the samples were tested for its strengths. The experimental results are discussed in this paper.