Effect of crumb rubber on the shear strength of a fine sand

The objective of this thesis was to determine the feasibility of using crumb rubber to reinforce sand. Direct shear tests were conducted on mixtures of sand and crumb rubber in order to determine if crumb rubber content and size were factors in improving the shear strength of the sand. Results of the direct shear tests showed that both crumb rubber size and content are significant factors in the overall shear strength of the mixture: As crumb rubber size increased, the shear strength of the mixture increased. As crumb rubber content increased to 7% by weight, the shear strength increased. At higher contents of crumb rubber, the shear strength of the mixture decreased. Adding 8-mesh crumb rubber increased the shear strength of the sand for all contents investigated, yielded an angle of internal friction as high as a 40.3% increase relative to pure sand. For 20-mesh crumb rubber, 7% crumb rubber content increased the shear strength of the sand by 30.2%. The 40-mesh crumb rubber increased the shear strength of the sand by as much as 20%.