Results in Materials (Dec 2023)
Synergistic impacts of fly ash and sugarcane bagasse ash on performance of polyvinyl alcohol fiber-reinforced engineered cementitious composites
Abstract
Disposal of waste materials in fertile land is one of the pressing environmental issues, disrupting human, animal, and plant life. This has led researchers to process and use such waste materials in ecofriendly construction products like mortar and concrete. Their usage as supplementary cementitious materials (SCMs) would reduce the quantity of cement utilized in the manufacturing of cement-based materials, lowering carbon dioxide emissions related to cement production. In this regard, this study examines the feasibility of replacing high-volume of ordinary Portland cement in engineered cementitious composites (ECCs) with two widely employed waste materials, sugarcane bagasse ash (SCBA) and fly ash (FA) as SCMs. Five different mixes were produced, each containing a fixed amount of polyvinyl alcohol (PVA) fibers at a dosage of 1.5% by volume of the mix and a constant cement content of 50% by weight of the binder (Cement + FA + SCBA). However, FA was replaced with SCBA in these mixes up to 100% by the combined weight of the waste materials (FA + SCBA) in increments of 25% (i.e., FA100-SCBA0, FA75-SCBA25, FA50-SCBA50, FA25-SCBA75, and FA0-SCBA100). The results showed that the compressive and flexural strengths of ECCs with increasing the levels of SCBA were reduced. Interestingly, the 28-day compressive strength of ECC incorporating 50% FA and 50% SCBA was still as high as 25.58 MPa, which satisfied the minimum compressive strength requirement of ASTM C270, making the newly produced ECC suitable for use in normal construction works and repairs. The same optimum mix (FA50-SCBA50) produced an average density of 1867.96 kg/m3 as a result of substituting a significant amount of the binder with SCBA, demonstrating that it has evolved into a lightweight ECC. Furthermore, the ultrasonic pulse velocity of the mixes decreased, whereas the water absorption increased as the proportion of SCBA to FA increased. According to the microstructural analysis, unreacted SCBA particles were mostly responsible for the detrimental effects of rising the SCBA levels on properties of ECCs. Based on the aforementioned results, this research concluded that SCBA, when combined with FA, could be a viable alternative for replacing regular cement up to 50% by weight in the production of cost-effective and environmentally friendly ECCs.
