Effect of Date Seed-Ash Stabilization on the Behavior of Expansive Soil

One of the challenges that has been faced by civil engineers is the damage to structures due to expansive soils. When such soils get wetted, their volume increase and due to drying, they shrink and the volume decreases. Consequently, this causes serious damages especially to lightly loaded buildings and pavements. In this study, an attempt has been made to solve the expansive soil problem in Gazimagusa, North Cyprus by using the waste product, date seed ash, DSA as a soil stabilizer. In Libya, the dates are cheap and available in huge amounts. The seeds of dates are the waste generated by some factories producing dates' jam. In the study, laboratory tests have been performed to study the effect of DSA as a soil stabilizer on the expansion and compressibility of the expansive soil. The effect of wetting-drying cycles on the volume change characteristics of the soil was also investigated. The soil was mixed with three percentages of DSA: 4%, 6%, and 8 % and laboratory tests were performed on both natural and treated soils. These tests include the hydrometer, compaction, Atterberg limits, unconfined compression, one-dimensional consolidation-swelling, cyclic wetting-drying and California Bearing Ratio (CBR) test. Test results show that addition of DSA into the soil resulted in a decrease in the plasticity and the swelling potential of the treated soils. However, DSA treatment caused a reduction in the unconfined compressive strength due to reduction in dry density of the treated soils. DSA treatment did not contribute to the improvement of the CBR value of the treated soils. From the obtained results, it can be concluded that DSA could be a good soil stabilizer for improving the plasticity and the swelling properties of the expansive soil but no improvement in the unconfined compressive strength and the CBR number was obtained. Keywords: Compressibility, date seed ash, expansive soil, plasticity, soil stabilization, swelling soil, wetting-drying cycles.