Sustainable Production of Fly Ash Based Coarse Aggregates and its Performance in Concrete

Abstract

An optimization study was carried out for the sustainable production of fly ash based coarse aggregates from the industrial by-products such as fly ash, considering the combined effect of geopolymerisation and pelletization. The trial mixes during the process of producing the fly ash based coarse aggregates were designed through Taguchi’s experimental design method. The combined effect of geopolymerisation and pelletization factors in the production process and engineering properties of the produced fly ash based coarse aggregates were evaluated using response indices at different curing ages. Further, the influence of each individual factor of geopolymerisation and pelletization on the engineering properties was determined through Grey relational analysis to identify the most influencing factors in the production of fly ash based coarse aggregates. The results obtained from Grey relational analysis indicate that the properties of produced fly ash aggregates are governed mostly by geopolymerisation. It is also observed that water content of 20 % by mass of fly ash found to be essential for the suitable production of fly ash based coarse aggregates. Artificially produced fly ash aggregate were used in the production of concrete with partial replacement of natural aggregates and it is found that for the production of M40 grade durable concrete, up to 30% by its volume can be replaced effectively.