Abstract: In order to improve the engineering properties of Guilin red clay and to increase the utilization of recycled tires, the lightweight tire rubber particles with grain sizes of 0.5 mm, 2 mm and 4.75 mm were blended into the red clay samples for the improved light compaction test and the direct shear test. The effects of different ratios and different particle sizes on the compaction characteristics and shear strength of the red clay showed that the maximum dry density decreased with the increase of the mixing ratio, and the optimum moisture content decreased. The rubber particle mixing ratio was between 2% and 8%, the shear strength increases; the increase of the shear strength of the rubber particle of 0.5 mm in grain size in the red clay is mainly caused by the increase of internal friction angle. The shear strength of 2 mm rubber particle within the red clay increases by both the cohesion and the internal friction. Caused by the increase of the angle; the increase of the shear strength of the 4.75 mm rubber particle red clay is mainly caused by the increase of cohesion.

Key words: Red Clay with Rubber Particles, Compaction Characteristics, Shear Strength