Effect of fiber reinforcement on triaxial shear behavior of cement treated sand

Conventional triaxial compression tests were conducted to determine the effect of cement and polypropylene fiber reinforcement on sand. The cement content was 3% (dry wt.) of the sand and specimens were cured for seven days. Fibers 0.012 m in length and 23 μm thick were added at 0.0%, 0.5% and 1% (dry wt.) of the sand–cement mixture. Samples were prepared at 50% and 70% relative densities and triaxial tests were performed at confining pressures of 100, 300 and 500 kPa. Stress–strain and volume change behavior, and stiffness and energy absorption of the soil were measured and compared with results of previous studies. The addition of fibers increased peak and residual shear strengths of cemented soil and changed its brittle behavior to a more ductile one. Initial stiffness for 0.1% axial strain decreased as fiber content increased. Adding fiber increased the energy absorption by 20–50%. Fibers were more effective on shear strength parameters at 70% relative density.