Evaluating the influence of fly ash and waste glass on the characteristics of coconut fibers reinforced concrete

Abstract The disposal of waste from coal plants and waste glass (WG) is causing significant environmental problems all around the planet. Currently, the amount of discarding of these wastes is increased. One possible option is to utilize fly ash (FA) from coal plants as a partial substitute for the cement and EG as a fractional substitute for sand in concrete, respectively. Besides, fibers can improve the strength and durability of concrete; explicitly speaking, using coconut fibers (CFs) is in trend due to their highest toughness among natural fibers making it suitable material as fiber reinforcement in concrete. This research studies the concrete behavior with 15% FA as a partial substitute of cement with 2% CFs and waste beverage glass as sand at various replacement levels (14%, 15%, 16%, 17%, 18%, 19%, and 20%). Mechanical and durability characteristics of concrete were assessed, such as compression strength, water absorption, flexural strength, density, workability, and water absorption. The current study results show that adding FA, CFs, and WG improved microstructure quality at 16% replacement of sand. The study showed that the M4 mix has enhanced the properties of concrete samples as compressive and flexural strength was improved to 47.2 and 6.2 MPa and improved apparent density by 20%. Adding more WGP than the optimal proportion (16%) led to detrimental effects on void ratio, permeability, and water absorption. Therefore, 16% of sand with WG and 15% of FA with cement can be substituted with 2% CFs to develop sustainable concrete.