Nowadays, the incorporation of natural fiber, such as coir fiber, to high-strength concrete has sparked a lot of attention in the construction materials industry. This is because coir fibers are significantly cheaper and more widely accessible than synthetic fibers. Natural fibers such as bamboo, flax, hemp, and coir have distinct microstructures and chemical compositions from cement-based materials. The physical and mechanical properties of natural fiber, such as coir fiber, are significantly correlated with fiber concentration and cellulose component. However, coir fiber has high stretching to failure, while bamboo, flax, and hemp fibers are very resistant to stress and increase stiffness. Based on these distinctive fiber qualities, it is anticipated that coir fiber would facilitate the development of cement-based materials for advanced concrete building applications. In this paper, coir fiber-reinforced cement-based concretes were evaluated in terms of workability, compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, and permeability. The relationship between strength and fiber content was analyzed to understand the impact of coir fiber on the properties of coir fiber-reinforced cement-based concrete. Based on the results obtained, it is determined that 2% coir fiber modification offers the highest compressive strength, splitting tensile strength, and flexural strength. Moreover, the modulus of elasticity is increased, and the permeability is plummeted by the volume fractions of coir fiber 1%, 2%, and 3% because the blending of coir fiber has a bridging and dispersing mechanism of the force-carrying capacity in concrete. In conclusion, coir fiber might be a viable choice for improving the strength and durability of concrete. Therefore, the sparing use of coir fiber presented in this research can be implemented for the manufacturing of concrete in the future.

Synthetic fibers are normally used as reinforcing material to strengthen the concrete. Natural fibers have been considered as the most sustainable alternative for synthetic fibers in both cost and sustainability point of view. In this study, mechanical characteristics of pre-treated bamboo and jute fiber-reinforced concrete (FRC) composites have been evaluated. The performance of treated natural fibers in the enhancement of strength of concrete has been examined. Fibers were added in the percentage proportions of 0.5, 1, 1.5, 2, and 2.5 by the weight of cement in the concrete matrix. The compressive and flexural strength of fiber-reinforced concrete has been experimentally verified. The test results show that maximum compressive strength was obtained as 26.4 MPa and 26.1 MPa for concrete with 1.5% bamboo and 2% jute fibers, respectively, at 28 days of curing. Similarly, maximum flexural strength was obtained as 6.36 MPa and 6.1 MPa for concrete with 1.5% bamboo and 2% jute fibers, respectively, at 28 days of curing. Based on the maximum compressive strength and flexural strength, optimum dosage of treated bamboo and jute fiber has been identified as 1.5% and 2%, respectively. SEM analysis reveals that there is a good bonding between fibers and concrete matrix, and breaking of fibers is due to pulling load and debonding.