Studies on the Strength Development of Lime-Pozzolana Cement- Soil-Brick Powder Based Geopolymer Composites

摘要

It is well known that geopolymer products can be made using materials that are rich in silica and alumina with alkalis as polymerisation agent. The chemical reaction, also known as poly-condensation, takes place with the assistance of thermal and/or mechanical activation. This paper discusses the production of moderate-strength geopolymer cubes using two sources of locally available raw materials, viz. soil and brick powder (BP). Instead of using industrial by-products such as fly ash and ground granulated blast furnace slag an attempt has been made to produce lime-pozzolana cement (LPC) on a very small scale and use it as an activator. The major objective was the production of geopolymer cubes which can eventually be used in masonry applications. Initially, a series of tests were conducted, by varying the proportion of soil and brick powder, to produce cubes with moderate strength (3.5-10.0 MPa). The studies revealed that the strength gain was due to contribution of pozzolanic reaction as well as polymerisation. The strength gain has been further enhanced by thermal activation at ambient temperature and mechanical activation by inter-grinding of LPC, BP and soil. This paper provides the details of production and characterisation of LPC and the strength characteristics of geopolymer-LPC-based cubes.