Effect of fly ash and waste glass powder as a fractional substitute on the performance of natural fibers reinforced concrete

Abstract

Stockpiling and landfilling of waste glass (WG) is becoming a severe environmental issue around the World as hundreds of tons of WG are dumped on the land. The present research assesses the behavior of WG in a concrete mixture as a partial replacement of sand to attain the optimal percentage of waste glass. Due to the production of ordinary Portland cement (OPC), the natural reserves of limestone are depleting fast, and the production of OPC also leads to a high proportion of carbon dioxide (CO2), so it is essential to utilize industrial by-products such as fly ash (FA) to replace cement partially. In the current study, the WG is used as a fractional substitute of sand in different proportions (14 %, 15 %, 16 %, 17 %, 18 %, 19 %, 20 %), with 20 % FA as a replacement for OPC, with 2.5 % coconut fibers (CFs) to improve the flexural strength of concrete. Engineering properties such as compressive and flexural strength, water permeability, sorptivity, density, voids ratio, resistance against fire, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) spectra were assessed. The outcomes showed that the M4 mixture (WG16-FA20-CFs2.5) had the utmost optimal performance, as 15.8 % and 9.57 % compression strength and flexural strength were improved at the curing of 90 days. During exposure of samples to fire, concrete with 16 % WG lost only 38.7 %, 44.2 % mass and compressive strength at 600 °C, which was the most lowered among other mixtures. Because of the utilization of FA, the concrete’s matrix gets denser, leading to improved water-related characteristics of concrete. It was observed that adding more than 16 %, WG led to reduced strength and durability properties of concrete. The current research confirmed that the 16 % WG, 20 % FA, and 2.5 % CFs could be replaced in concrete to produce improved, eco-friendly concrete.