PSI - Issue 70

S. Rajeshkumar et al. / Procedia Structural Integrity 70 (2025) 287–294

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1. Introduction The construction industry faces major environmental scrutiny because of excessive cement consumption since it produces major environmental degradation (Nabilla et al.,2022) The construction field generates a major percentage of planetary greenhouse gas emissions thus demanding scientific investigation into new materials for building construction that minimize environmental harm without losing strength capabilities (Soomro et al., 2023). Modern infrastructure depends on Cement to bind its fundamental component known as concrete. The production methods of cement require significant amounts of energy while being environmentally damaging due to its CO₂ emissions of 0.9 tonnes per tonne of cement manufactured (Scrivener et al., 2018). The cement industry contributes over 8% of total global CO₂ emissions, making it a significant source of greenhouse gases (Mehta, 2001 ). The manufacturing process of cement requires large quantities of natural resources which destroy habitats and reduce the availability of limestone resources (Habert et al., 2020). The use of agricultural waste ashes has emerged as a sustainable concrete ingredient recently. The ashes can be used to substitute cement in certain proportions while also increasing concrete strength along with durability. Rice Husk Ash (RHA), Bagasse Ash (BA), Groundnut Shell Ash (GSA), and Palm Oil Residue Ash (PORA), along with Corn Husk Ash (CHA), possess alumina and silica that create a strong binding gel by reacting with cement lime content (Asad et al., 2024; Olutoge,2010; Thomas et al., 2021; Reddy et al., 2017; Nwaobakata, 2018). Durability properties of RHA and SCBA offer better acidity resistance along with reduced water absorption (Zain et al., 2011). The reutilization of waste ashes provides two environmental benefits by lowering cement requirements and offering eco friendly material disposal practices. RHA gains its designation as a highly reactive pozzolanic substance by the regulated combustion process that alters rice husks. RHA comprises elevated concentrations of amorphous silica that engage in a chemical reaction yielding supplementary calcium silicate hydrate gel (C – S – H), hence enhancing concrete strength (Ganesan et al., 2008; Bui et al., 2005; Habeeb et al., 2009; Chandrasekhar et al., 2003; Alex, et al.,2022). GSA produced through groundnut shell incineration which consists of silica as well as alumina and additional oxides which exhibit pozzolanic activity. The incorporation of GSA within concrete produces enhancements to compressive strength and decreased water absorption alongside better concrete microstructural quality (Sani et al.,2023). This present research investigates the mechanical and durability properties of M30 grade concrete incorporating varying proportions of RHA and GSA as partial replacements for cement. These agricultural by-products serve as cement replacement materials to solve the environmental problems which traditionally affect the cement production process. The modified concrete performance assessment involved direct comparisons with conventional concrete to evaluate structural reliability and determine long-term behaviour. This study demonstrates critical importance because it develops sustainable building techniques based on agro-waste materials while maintaining modern construction standards. 2. Materials The main binding substance was OPC of 53 grade, in compliance with IS 12269 criteria. Its standard consistency was 31% and its specific gravity was 3.15. M-sand was employed as the fine aggregate in lieu of natural river sand. It was sourced from a local crusher facility and conformed to the grading specifications of Zone II according to IS 383:2016. The sand passed through a 4.75 mm sieve and was found to be clean, angular, and devoid of silt and clay. The specific gravity was 2.65, and the fineness modulus was 2.8. The crushed hard blue granite particles were used as the coarse aggregate with the maximum size of 20mm. The specific gravity was 2.74, and the water absorption rate was 0.55%. The aggregates were unblemished, robust, and angular, conforming to IS 383:2016 requirements. Potable water, suitable for both mixing and curing, was used during the testing procedures. Rice husk ash (RHA) was produced by incinerating rice husks sourced from local rice mills under regulated settings at temperatures ranging from 600 to 700°C. The ash was subsequently pulverized and sifted to achieve a fine powder with a particle size under 75 microns. Groundnut shells collected locally were dried in the sun and burned to form GSA which was later ground into powder with average dimensions smaller than 75 microns. The key properties of RHA and GSA is listed in Table 1. Fig.1. illustrates the image of RHA and GSA.