Performance of High-Strength Concrete with the Effects of Seashell Powder as Binder Replacement and Waste Glass Powder as Fine Aggregate

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.