SCIENCE AND ENGINEERING OF COMPOSITE MATERIALS, cilt.20, sa.4, ss.395-405, 2013 (SCI-Expanded)
Dispersive and expansive soils are considered problematic, and these soil properties cause serious problems for many engineering structures. For many years, comprehensive studies have been carried out with the aim of improving the swelling and dispersive qualities of soils by using additives. Each feature in the literature associated with the improvement of the dispersive and swell properties of clay soil with additives was separately evaluated. In this study, the effect of cement and natural zeolite additives on the characteristics of dispersibility and swelling potential of clay soils were investigated. A fixed percentage of cement (3%) plus different percentages of natural zeolite (1%, 3%, 6%, 10%, 15%, and 20%) were mixed with four different clay soil samples. In this context, first, the physical and chemical properties of the soil samples were determined. Next, the swell percentage, swell pressure, crumb, pinhole and unconfined compressive strength tests at different curing times were performed on samples with and without the additive by compressing the sample to achieve particular compaction characteristics. Significant strength value increases depended on curing time, and the properties were improved with the mixture of cement and zeolite additives, depending on the sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values of clay soil samples with different plasticity characteristics that exhibit dispersive and swell properties. This study not only showed that a mixture of cement and zeolite additives improved the dispersive and swell properties of clay soil samples with four different plasticity characteristics, depending on their SAR and ESP values, but also significant increases in strength values were observed.