An attempt to shed light on the use of agro-industrial-based wastes as supplementary cementitious material (SCM) or as alkali-activated binder (AAB) material is mainly focused in this review paper. The SCM or AAB acts as a suitable replacement for cement, as the cement manufacturing tends to contribute to 8–10% of global CO2 emissions. To gain acceptability in the construction industry, diverse agro-industrial-based wastes must demonstrate their potential as precursors in AAB or as SCM. The binder materials discussed among the agricultural wastes are rice husk ash, olive waste ash, and coconut-based waste ash, and the industrial wastes are ground granulated blast furnace slag, fly ash, and ultra-fine steel slag. The paper also analyses the effects of calcined and uncalcined agro-industrial-based wastes on pozzolanic properties of binder system. It is clear from the studies that the calcined wastes tend to provide greater reactivity compared to the uncalcined wastes, that helps in early strength development in the binder system. The review findings indicate that the agro-industrial-based wastes provide pozzolanic and hydraulic properties, thereby making them suitable as an AAB or as a SCM.
Seashell powder (SSP) is a waste from aquatic life that is generally available near the coastal region. Due to its high calcium content, SSP can be utilized as a supplementary cementitious binder. SSP can be used as a sustainable binder to replace ordinary Portland cement (OPC) and significantly reduce the carbon footprint. The present study investigates the effects of SSP and waste glass powder (WGP) on the fresh, mechanical, and microstructure properties of high-strength concrete (HSC). The SSP utilized in this research was varied, with 5%, 10%, and 15% cement replacement levels. The impact of WGP was also observed with two replacement levels, 5% and 10%, replacing natural sand. The slump flow of all the HSC mixes varied between 700 and 785 mm. A maximum compressive strength of 112.91 MPa was found for the C75SSP5 mix at 56 days. The split tensile strength values of all the HSC mixes were found in a range from 5.45 to 10.56 MPa. The modulus of elasticity values of all the HSC mixes were found to lie between 40.2 and 46.8 GPa. The lowest water absorption was observed in the mix containing 5% SSP. The SEM image of the HSC with increased SSP showed that it was denser and had fewer unreacted particles. XRD and EDS showed the presence of various gels, such as calcium silicate hydrates (CSHs), ettringite, calcium hydroxide (CH), and calcium carbonate (CC). The predicted equations for its split tensile strength, flexural strength, modulus of elasticity, and water absorption were also carried out in the present research.
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