Masters Thesis

Improving Weak Clay Properties with Shredded Rubber Tires.

Large amounts of waste materials such as waste tires, rubbers, etc. are discarded into our surrounding environment. Thus, they are a major cause of contamination and pollution, which, as a result, could eventually lead to many problems including health hazards and fire. Therefore, engineers, environment scientists and researchers face a challenge of how to deal with discarded tires. Undoubtedly, the best solution to not only get rid of waste tires but also make use of them through recycling. Thus, recycling tires would ultimately yield a cleaner environment and prevent public health degradation. Moreover, shredded tires have been used in many geotechnical as well civil engineering applications such as highway embankments, bridge abutments and backfills behind retaining structures. Shredded tire material has also been used to modify soils. Certain clay properties such as poor drainage, high compressibility, and low shear strength make it unfavorable for civil engineering applications. Modifications can be made in these properties by mixing clay with shredded tires. This study focuses on improvements obtained in clay properties by using different sizes of shredded rubber tire. Granular kaolin and a mixture of 50% montmorillonite with 50% granular kaolin were modified using different sizes and percentage of shredded rubber tire. Laboratory experiments were carried out to evaluate the changes in unit weight, permeability and unconfined compressive strength characteristics of the modified clay. The results presented in this thesis include the properties of granular kaolin and a mixture of 50% montmorillonite with 50% granular kaolin mixed with shredded rubber tires. According to the test results, the maximum dry unit weight occurs at 2 to 4% of shredded rubber tires are added to the clay soil samples for all sizes of shredded rubber tire. The highest strength for the mixture of granular kaolin and tire was obtained at when 3 to 4% shredded rubber tire was added into the soil. The maximum unconfined compressive strength for a mixture of 50% montmorillonite with 50% granular kaolin was obtained at approximately 4% shredded rubber tire for all sizes. Moreover, when less than 10% shredded rubber tire was added to granular kaolin, little changes in the coefficient of permeability were observed. When more than 10% shredded rubber tire was added, the coefficient of permeability increased as the percentage of shredded rubber added increased.


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