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 determine
optimum 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.