Coir-fiber reinforced soil-cement block as walling material for rural houses

An investigation was undertaken to develop stabilized soil-cement blocks reinforced with coir fiber for use as a walling material in rural houses. The study evaluated the physical (density, water absorption) and mechanical (compressive and tensile strength) properties of the blocks. The soil sample consisted of 25% sand, 54% silt, and 21% clay, with a liquid limit of 32.8% and a plastic limit of 22%, and was classified as silt-loam. The maximum dry density and optimum moisture content were 1.61 g/cc and 20.83%, respectively, with a specific gravity of 2.60. Ordinary Portland Cement (OPC) was used for stabilization. Coir fibers, cut to 4 cm, were incorporated at 0, 0.2, 0.4, 0.6, and 0.8% by soil weight. To prevent water absorption, tar was applied to the fibers, which had a tenacity of 11 g/tex. A total of 40 blocks were prepared and cured for 28 days. Results showed that compressive and split-tensile strengths increased with fiber content, while density decreased. Compressive strength ranged from 360 psi (0% fiber) to 1136 psi (0.8% fiber), and split-tensile strength from 30.03 psi to 72.03 psi. Water absorption increased with fiber content, and unit cost also rose. The addition of 0.8% fiber significantly enhanced strength, suggesting that coir-fiber-stabilized soil-cement blocks could provide a durable alternative to traditional mud houses.