Synthesis of geopolymer coarse aggregates using class-f fly ash and studies on its physical properties

Abstract

Industrialisation in developing country is the major scenario, due to which there is depletion of natural resource [1], like reduction in availability of naturally available aggregates and manufactured aggregates [2]. The best way to protect our natural resource is to give more importance to alternative materials [3] which can easily be replaced with the natural ones. In the present study, fly ash which is a by-product obtained from thermal power plants, and other coal industries are mixed with activator solution to prepare aggregates. Activator solution is prepared by mixing sodium hydroxide and sodium silicate in varying ratios. Fly ash and part of M-sand is mixed with prepared activator solution to form slurry. This slurry is cast into cubes of size 150 × 150 × 150 mm and oven dried for two hours and then the cubes are kept in normal room temperature for one week; later, cubes are crushed manually or by using crusher. These newly formed aggregates are sieved according to IS specification. Basic tests were carried out on the prepared geopolymer coarse aggregate. According to test results, it can be concluded that geopolymer aggregates have less specific gravity and higher water absorption compared to natural aggregates, and also it shows even particle size distribution. This paper is in accordance with IS specifications.