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Item Optimisation of Cement Mortar Performance Through Bagasse Ash as a Sustainable Supplementary Material(Springer Science and Business Media Deutschland GmbH, 2024) Majeed, P.M.M.; Baby, B.; Palanisamy, T.Bagasse ash, a residue from the processing of sugarcane, has the potential as an environmentally friendly addition material for waste valorisation in the building sector. This study used different amounts of bagasse ash to partially substitute cement to examine the mechanical and durability aspects of cement mortar. The experimental matrix involved substituting the cement with bagasse ash at dosages of 5, 10, 15, and 20%. Using compressive strength, flexural strength, ultrasonic pulse velocity (UPV), and rapid chloride penetration tests (RCPT), both the durability and mechanical characteristics of the various mixes were studied. The results revealed that a bagasse ash dosage of 15% emerged as the optimum level, demonstrating superior mechanical and durability performance. For measuring compressive strength and UPV, mortar cube specimens measuring 70.6 mm × 70.6 mm × 70.6 mm were cast; prism specimens measuring 40 mm × 40 mm × 160 mm were formed for the assessment of flexural strength; and cylindrical specimens measuring 100 mm in diameter and 200 mm in height were cast for RCPT. The significant improvement in the compressive and flexural strengths demonstrated the beneficial impact of bagasse ash on the mortar's structural integrity. Furthermore, UPV measurements revealed enhanced internal cohesion and homogeneity in the mortar matrix. Moreover, the findings of the RCPT demonstrated a noteworthy decrease in the penetration of chloride ions, highlighting the capacity of bagasse ash to alleviate the risk of corrosion on reinforcement. This study emphasises the importance of using bagasse ash as a sustainable alternative for waste valorisation in cementitious systems. An optimised dosage of 15% enhanced the mechanical and durability properties and contributed to the eco-friendly disposal of agricultural waste. These findings support the adoption of bagasse ash as a viable supplementary material to promote environmental sustainability and improve the performance of construction materials. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Item An experimental investigation on mitigating cracks and augmenting the endurance of concrete structures in marine environment by bio-mortar immobilised with halophilic bacteria(Elsevier Ltd, 2024) Baby, B.; Palanisamy, T.In coastal areas, built structures encounter hostile conditions and forces that can cause them to deteriorate over time owing to saltwater exposure, tidal forces, reinforcement corrosion, and freeze–thaw cycles. Early age cracks in such structures accelerate the rate of deterioration, and the current research focuses on alleviating such threats. This paper evaluates the performance of a self-healing mortar made by encapsulating expanded perlite with the bacterium Halobacillus Halophilus MCC2188. Mortar cube specimens of size 70.6 mm × 70.6 mm× 70.6 mm were prepared with cement: fine aggregate in 1:3 ratios. A 10% volume of the fine aggregate fraction was substituted with the expanded perlite immobilised with bacterial spores and nutrients. The expanded perlite aggregates were coated with sodium silicate and cement solution to protect the spores from the nonconducive environment. The specimens were subjected to fully and partially submerged marine water curing. The mechanical properties and self-healing potential were evaluated, and the precipitated polymorphs in completely healed cracks were identified and examined by characterisation techniques such as XRD, FEGSEM, FTIR, and TGA-DTG. The marine bacterium under investigation can tolerate the high salt concentrations commonly found in seawater and saline marshy soil and produce calcite through the metabolism of organic compounds, making it a suitable microorganism for self-healing applications. Crack widths of up to 0.84 mm and 92.79% average strength recovery were achieved in 56 days post-cracking, and the pace of healing was quicker in partially submerged curing conditions. The results showed improved self-healing, strength regain and mechanical strength and proved to be an efficient tool for enhancing the endurance of biomortar in severe marine exposure conditions. © 2024 Elsevier Ltd