AN EXPERIMENTAL STUDY ON BEHAVIOUR OF COMPOSITE SOIL MADE OF WASTE MATERIAL AND CEMENT

Abstract

Large quantities of waste tires can be beneficially used by incorporating them into structural fill employed in earthwork projects such as highway embankments and backfills for retaining structures. These applications require knowledge of the bulk mechanical properties of tire chips and soil-tire chip mixtures. The growing interest in utilizing waste material in civil engineering has opened the possibility of reinforced soil structures like roads and embankments. Scrap tires are high profile, light weight, waste materials potentially suitable for harsh environment due to their chemical and corrosion resistant properties. Incorporation of tire chips in the backfill results in a reduction in unit weight and, for mixtures containing sand or sandy silt, an increase in shear strength. In contrast, clay-tire chip mixtures have the same or lower shear strength as clay alone. Strength envelopes for sand-tire chip mixtures can be nonlinear, and have virtually no cohesion intercept. Mixtures containing sandy silt behave similar to mixtures made with sand, except the shear strength envelope for the sandy silt tire chip mixture which is linear and has cohesion intercept. Sand-.tire chip and sandy silt-tire chip mixtures exhibit similar long-term compression behavior. Various engineering properties must be known to assess the feasibility of using shredded scrap tires as drainage material in landfill cover systems. These properties include unit weight, hydraulic conductivity, compressibility, shear strength, and interface shear strength. The major reason to introduce shredded rubber in a stabilized soil is to decrease the soil modulus without diluting the cement content. Low cement content increases the risk for in homogeneity in the stabilized soil. The shredded rubber acts like an imaginary porosity in the stabilized soil and thereby decreases the modulus. Since air voids could soak water, this will decrease the performance of stabilized soil. One of the key parameters for obtaining a high quality in soil stabilization is compaction. The compaction result of a stabilized soil is dependent of applied/adopted compaction energy, water content in a soil/binder mix and the working period of binder.