Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Bacillus Subtilis Immobilised Areca Fibre Mortar for Robust Self-healing(Springer Science and Business Media Deutschland GmbH, 2024) Sai Teja, A.; Palanisamy, T.; Anoop, P.P.; Gopal, M.This study focuses on developing a bacteria-based self-healing mortar by immobilizing bacteria with Areca Nut Husk Fibre (ANHF). ANHF is an agricultural waste that is eco-friendly, lightweight, renewable, and sustainable construction material. The objectives of this study include determining the optimal ANHF percentage, self-healing potential, mechanical properties, and durability performance of developed mortar. The type of carrier material significantly influences the viability of bacteria and their calcite precipitation ability in self-healing concrete. The present study examined the possible application of natural fiber, ANHF and to carry bacterial spores that maximize-healing potential while maintaining structural integrity in concrete. Along with Bacillus subtilis VEB4 bacteria, calcium lactate pentahydrate and, urea are used as organic nutrients. The study examined the effect of adding ANHF at different volumes of mortar (0, 0.25, 0.50, 0.75, and 1%).The mortars showed the maximum mechanical strength at an ANHF content of 0.75%. The fiber-reinforced bacteria-immobilized mortars exhibited 100% healing. A maximum crack width of 0.813 mm was healed after 56 days, while controlled specimens healed partially. SEM, FTIR and, XRD tests on Fibre bacterial mix revealed that calcite is the predominant mineral substance with a few microbial imprints on the crystalline surface. Mechanical property analysis includes compressive and flexural strength evaluations. The research assesses the material’s durability through resistance to alkaline and acid substances. The findings aim to contribute to sustainable construction materials by offering an eco-friendly solution to concrete deterioration. The optimized microbial mortar, with improved self-healing, robust mechanical properties, and durability, holds promise for applications in civil engineering, promoting resilient and long-lasting concrete structures. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.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 Impact of Hemp Fiber on Mechanical and Durability Characteristics of Bacterial-Based Cement Mortar(Springer Science and Business Media Deutschland GmbH, 2025) Pandey, D.; Chaudhary, P.; Palanisamy, T.Natural fibers are currently highly valued due to the need for environmentally friendly alternatives. Integrating self-healing bacteria with natural fiber-reinforced mortar creates a unique and sustainable building material that enhances strength and facilitates crack repair. This study evaluates the performance of natural fiber and bacteria in improving the mechanical properties and durability of impaired mortars. The methodologies adopted include a bio-based approach incorporating directly added bacteria and a bio-based strategy utilizing bacteria and fiber reinforcement. Bacteria were identified from a suitable environment and directly added to the cement mortar, along with varying percentages of hemp fibers (0, 0.25, 0.5, and 1). Intentionally induced cracks, subjected to 80% peak compressive stress, undergo water curing with regular monitoring. The effects of hemp fiber content and pH value of acid attack on the mass loss of tested concrete were investigated. The results indicate that the Bacillus strain, Bacillus licheniformis, achieves higher values in compressive strength and lower values of sorptivity tests by 26% and approximately 7%, respectively, with the incorporation of 0.5% hemp fibers leading to a 25–30% increase in 28-day compressive strength. Microstructural investigation reveals that microbial-induced precipitation of various calcium carbonate polymorphs densifies the porous microstructure of the cement matrix. The process was analyzed using SEM imaging to observe bacterially induced carbonate crystals, while FTIR spectroscopy was employed to reveal the variety of CaCO3 crystals formed and to predict the bonding mechanisms responsible for calcium carbonate formation. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.