Laboratory Study on the Relative Performance of Silty-Sand Soils Reinforced with Linen Fiber

Randomly distributed fibers have been successfully used for the reinforcement of soils to improve their properties. However, the technique requires extensive testing on samples before it can be implemented. Therefore, the purpose of this paper is to identify and quantify the influence of variables of linen-fiber (content and aspect ratio) on the performance of linen-fiber reinforced silty-sand specimens. The linen fibers have filament textures with special properties such as: low costs, plenitude in the region, lightweight, tension capacity and relative strength against deterioration. Linen fibers with diverse fiber contents (0.25, 0.50, 0.75 and 1.0% of dry weight) and ratio aspect (50, 100 and 150) were used. The composite soils were laboratory tested for compaction, unconfined compression strength (UCS), California Bearing Ratio (CBR) and direct shear tests. The test results indicated that adding linen fiber in silty-sand soil resulted in increasing in unconfined compression strength, California Bearing Ratio values, peak friction angle and cohesion values. Furthermore, adding linen fibers have the dual benefit of increasing the stiffness (modulus of elasticity) and the ductility of the reinforced soil. However, this study suggests that the optimum fiber content for silty-sand samples reinforced with linen fibers is approximately 0.75% of the dry weight of the soil and a maximum performance was achieved at aspect ratio of 100 to avoid fiber balling. The laboratory results were used for the development of linear regression equation that best relates the UCS and CBR of a reinforced soil to the aforementioned parameters.