Impact of Fiber Reinforcement on Deformation Characteristics of Cemented Sand-Gravel Mixtures

This paper describes triaxial compression tests conducted to determine the effect of fiber inclusion on stiffness and deformation characteristics of sand-gravel mixtures. the soil was a mixture of babolsar sand from the shores of the caspian sea and karaj river gravel in two different contents of 30% and 50%. the relative density of samples was 70% and 3% portland cement was used as the cementing agent. fibers of 12mm in length and 0.023mm in diameter added at 0%, 0.5% and 1.0% (wt. of dry soil) to the sand-gravel mixtures. the axial stress versus axial strain and volumetric strain or pore pressure changes have been assessed with the changes in stiffness during loading. based on the obtained results, fiber addition caused to increase soil shear strength. under drained conditions, fiber addition leads to increase initial compressive strains and ultimate dilation. it also increases initial positive pore water pressure and final suction in undrained condition. it has also been observed that fibers decrease initial tangent stiffness of the cemented sand-gravel mixture.