To Investigate and Optimize Concrete Properties Using Volcanic Ash, Nano Silica with Addition of Cotton Fiber

Abstract

Cotton Fiber Reinforced Concrete (CFRC) has emerged as a promising sustainable construction material, incorporating natural fibres to enhance concrete’s mechanical properties. However, to further improve its performance, it is essential to explore innovative additives. Nano Silica (NS) and Volcanic Ash (VA) are two such materials that have demonstrated potential in enhancing concrete\'s properties, especially in terms of strength and durability. This study investigates the synergistic effects of NS and VA on the mechanical properties and durability of CFRC, with a focus on its performance under various curing conditions. The primary objective of this study was to assess the effects of incorporating NS and VA in CFRC on its compressive strength, tensile strength, flexural strength, and durability. The durability tests focused on sulphate resistance, chloride ingress, and water permeability. The results showed a significant improvement in the compressive strength, tensile strength, and flexural strength of CFRC with the incorporation of NS and VA, especially in Mix M3. Mix M3 also showed superior durability, with the highest resistance to sulphate attack, chloride ingress, and water permeability. SEM and XRD analyses revealed a dense microstructure and enhanced hydration due to the NS and VA combination. This study confirmed that the synergistic incorporation of NS and VA significantly enhances the mechanical properties and durability of CFRC. Mix M3 (2.5% NS, 12% VA,1% CF) demonstrated the optimal performance, suggesting it as a high-performance material for structural applications in harsh environments.

Introduction

The text focuses on developing sustainable high-performance concrete by partially replacing conventional materials with volcanic ash (VA), nano silica (NS), and cotton fiber (CF) to reduce the environmental impact of cement production, which accounts for about 8% of global CO? emissions. Traditional concrete relies heavily on cement, aggregates, and natural resources, prompting the need for eco-friendly alternatives that maintain or enhance mechanical performance while lowering carbon footprint.

A review of existing studies shows that nano silica improves early and long-term strength by filling micro-voids, refining pore structure, and reacting with calcium hydroxide to form additional C–S–H gel, thereby enhancing durability and fibre–matrix bonding. Volcanic ash, a natural pozzolanic material, reacts with calcium hydroxide to improve strength, reduce permeability, and lower heat of hydration, making it suitable for large concrete structures. Cotton fibers, being lightweight, cellulose-based, and having high surface area, improve crack resistance, tensile strength, and flexural performance while reducing concrete density.

The experimental study used M45 grade concrete with five mix proportions: a control mix (M0) and four modified mixes (M1–M4) containing varying percentages of VA (9–15%), NS (2–3%), and CF (0.3–1%). Standard materials such as Ordinary Portland Cement, fine aggregate, and coarse aggregate were used. The concrete was tested for workability (slump test), compressive strength, tensile strength, and flexural strength at 7, 14, and 28 days of curing.

Results showed that workability decreased as the content of VA, NS, and CF increased due to higher surface area and fiber interaction. However, mechanical performance improved significantly. Compressive, tensile, and flexural strengths increased, with mix M3 (12% VA, 2.5% NS, 1% CF) consistently showing the best overall performance across all curing ages, especially in flexural strength. The combined use of NS and VA enhanced matrix densification and strength, while cotton fibers improved crack bridging and ductility.

Conclusion

This study successfully demonstrated the synergistic effect of Nano Silica (NS) and Volcanic Ash (VA) in enhancing the mechanical properties and durability of Cotton Fiber Reinforced Concrete (CFRC). The results showed significant improvements in compressive strength, tensile strength, flexural strength, and resistance to chemical attacks. The optimized mix (M3), containing 2.5% NS and 12% VA, exhibited the best overall performance and is recommended for use in high-strength and durable concrete applications. This research contributes to the sustainable development of construction materials and offers a cost-effective and environmentally friendly solution for the construction industry.

References

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Copyright

Copyright © 2026 Mr. Sunil Thakur, Mr. Sourabh Lalotra. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.