Evolution Effect of Nano-Glass Powder on the Strength Performance and Microstructure of High-Volume Fly Ash-Based Concrete Incorporated with Effective Microorganisms

Abstract

The use of high-volume fly ash (HVFA) as a cement substitute has elicited the attention of researchers because it minimises CO 2 emissions by reducing cement production. However, the low strength at early ages poses a major challenge to cement replacement with HVFA. Glass bottle waste nano-powder (GBWNP) may offer a promising material for increasing strength at early ages due to their availability and minimal cost. In addition, GBWNP has sufficient pozzolanic properties to assist the pozzolanic reaction that can compensate for the early age strength reduction associated with HVFA concrete. The objective of this research is to improve the performance of HVFA concrete by including nano-powder obtained from waste glass bottles and utilising the promising potential of efficient microorganisms (EMs). Results of the examined specimens show that the addition of nano-glass powder significantly improves strength indexes at all the tested ages. Furthermore, EMs contribute to compressive strength enhancement rates ranging from 3.1% to 28.1%, depending on the test age, compared with the samples that contained only 50% FA as cement replacement. The specimens with 10% EMs as mixing water replacement and 6% nano-glass powder demonstrate mechanical performance comparable with that of the control samples at 3, 7 and 28 days whilst outperforming them at 56 and 90 days. Furthermore, microstructural analysis results indicate that the addition of nano-glass powder improved the microstructure compactness and homogeneity of the specimens. By utilising fly ash and glass waste powder, this study also aims to benefit the environment by reducing pollution, recycling waste and resolving landfill issues

Keywords: Modified concrete, HVFA-based concrete, Effective microorganisms, Fly ash and Nano-glass