Stress-strain behaviour and strength properties of ambient cured geo-polymer concrete

Abstract

Given the high environmental impact of OPC concrete on CO2 emissions, the construction industry is moving towards low carbon alternate binders. In recent years geo-polymer concrete (GPC) has come to the forefront of such efforts. However, challenges remain for GPC to be considered as a main-stream construction material. Since GPC is relatively new material in construction industry, many of its mechanical properties are still not fully understood. The current work looks at the strength properties of ambient cured GPC. This research paper is part of an ongoing investigation on GPC and reports some results of the mechanical properties of ambient-cured GPC. In this study, the stress-strain behavior and compressive strength of such GPC and its dependency on various parameters (ratio and type of activator and proportions & type of pre-cursor materials) is investigated. The results indicate that the compressive strength of GPC is greatly dependent on the proportion of Ground Granulated Blast Furnace Slag (GGBFS) and ratio of activators. It was found that increasing the percentage of GGBFS increased the compressive strength but at the expense of setting time of the mix. The mixes that had GGBFS around 20% of the binder material returned a compressive strength of less than 25 MPa which may not be suitable for structural applications. Whereas, the increase in percentage of GGBFS from 20 to 80% resulted in compressive strength of 40 MPa and higher. The stress-strain relationship of the mixes was compared to two analytical models existed in the literature.