COMPACTION PERFORMANCE OF GROUND RUBBER AND CLAY MIXTURES

As a modified material, the waste tire granulated rubber is expected to enhance the effectiveness of liner system in landfill. The existing results of compaction tests are in conflict to some extent since the compaction mechanism is complex. The compaction test of waste tire ground rubber and clay mixtures is conducted and the effect of rubber properties on compaction performance is studied. When the rubber mixing content increases from 0% to 25%,the optimum water content of the Kaolin mixture increases and that of the red clay mixtures decreases. The change of optimum water content of the mixtures is within 2.4% and the maximum dry density decreases from 1.65gcm-3 to 1.40gcm-3.The 12-mesh and 30-mesh rubber used in the present study show no significant difference on the compaction performance. Under the two effects of rubber particle rebound and specific surface area change, the optimum water content can either decrease(for coarse rubber),be about the same, or increase(for fine rubber) with the increasing of rubber mixing content,.The change is closely related to the properties of the matrix soil. The control parameters of water content and dry density at the preliminary design are put forward, which can basically meet the water content and degree of compaction requirements of compacted clay liner in the specification. The hydraulic conductivity of the mixtures is below 1.010-7cms-1 and also meets the requirements.