EFFECT OF CEMENT ON COMPRESSIBILITY AND SWELL OF SAND-EXPANSIVE CLAY MIXTURES

Abstract

This paper investigates the effect of adding low percentages of cement on the swelling and compressibility characteristics of sand-expansive clay mixtures. The use of highly plastic clay is known for reducing the hydraulic conductivity which is the main goal of waste containment barriers. However, liners can act as cover layers, road base, or a supporting ground. Excessive swell is likely to cause damage to light structures. Recent studies called for using clay with low plasticity that is just enough to fill the voids. Other researchers suggested adding fillers of fine powder. This study is an attempt to reduce the high plasticity with the addition of cement. The expansive clay used in this research was obtained from Al-Qatif region in the Eastern Province of Saudi Arabia. For these mixtures, the sand was considered the host material, and the clay content varied between 10% to 40% by dry weight of sand. The proposed cement content is put as low as 1, 2, and 4% by the dry weight of mixture at curing periods of 1, 7, and 28 days. A series of onedimensional odometer tests were conducted to evaluate the swelling potential, swelling pressure, and compressibility characteristics of mixtures. Laboratory compaction tests were performed to determineoptimum moisture content and maximum dry density. The addition of cement was found to improve the engineering properties of the mixtures and stabilize and control the swell and compressibility of the liner material.