Evaluation of the mechanical behavior of different geopolymers via different experimental testing methods

Abstract

The rapid technological development in recent decades has resulted in the study of promising materials to replace the traditional cement concrete which its production massively contributes for polluting the environment by emitting CO2 gas. Geopolymer concrete (GPC) is a sustainable construction material that has captured the attention of scientists. This is due to its potential to minimize the carbon dioxide emissions and improve the mechanical properties of concrete. A mixture of metakaolin, normalized sand, and an alkali solution which is the activator are the main constituents of the GPC. In this study, the mechanical behavior of steel fiber reinforces geopolymer concrete (SFGPC) was investigated through tensile, compression, and flexural tests. The tests were conducted on specimens which were 7,28 and 56 days old. These were prepared with different steel fibers percentages of 0%, 0.15%, 0.25%, 0.5% and 0.75%. The purpose behind this work is to determine the impact of steel fiber reinforcements on the mechanical behavior of geopolymer concrete and to analyze the experimental data obtained. The results showed that the addition of steel fibers has a complex effect on the mechanical characteristics of GPC. Due to fluctuations of data with the absence of an obvious pattern, no remarkable changes were observed in ultimate strength and elastic modulus by increasing the amount of steel fibers in the mix. However, the elastic modulus decreased with time for all percentages, showing how the aging process makes the material more brittle. Another interesting finding was the decrease of the material strength in compression with time. Finally, recommendations for future studies on the SFGPC and notable experimental challenges that need to be addressed were presented.