Employment of Sisal Natural Fibers as Soil Reinforcement

The use of natural fibers as a reinforcement for soils is a technique known for a long time by humanity. This practice has a great performance as a reinforcement material for has a high tensile strength, promoting improvement in the mechanical properties of the soils, conferring gain of mechanical resistance and reduction of his compressibility. The performance of the mechanical behavior of clay-silt soil at the Brasília Landfill, Brazil is analyzed by reinforcing the soil with natural sisal fibers with lengths of 75, 50, and 25 mm for a 0.5% fiber content of the total volume of dry soil. The aim to finding the optimal fiber length for the analyzed percentage. The mechanical strength conferred to the soil when applying such reinforcement is analyzed using the California Bearing Ratio and simple compression tests, and the results are compared with those obtained in natural soil. The plastic deformation and the reduction of the voids index are analyzed through the consolidation tests for each sample. The 75 mm sisal fiber was expected to be more viable for the reinforced soil, but it presents great difficulty of homogenization with the soil and high agglomeration of the fibers, making it difficult to evaluate. However, the 50 mm fiber presented higher mechanical strength and greater readiness for homogenization with the soil for the 0.5% content analyzed.