Polymers for stabilisation of Wahiba dune sands, Oman

Abstract

Dune sands are problematic soils because they have low shear strength and are susceptible to collapse on wetting. In the work reported in this paper, polymers in different concentrations from 1 to 3% were used to improve the engineering properties of dune sands. The sand–polymer mixtures were allowed to cure for 7 to 28 d. Laboratory analyses such as compaction tests, unconfined compression tests, unconsolidated undrained (UU) triaxial tests, consolidated undrained triaxial tests, chemical analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were carried out to measure the engineering properties of the stabilised material. The results showed that the strength substantially increased with an increase in polymer content. For 3% polymer addition, the unconfined compressive strength (UCS) of the stabilised sand was about 4370 kPa. The UCS of a sand stabilised with 2% polymer was similar to that of sands stabilised with 12% cement and with 40% of cement-by-pass dust. The results of UU testing showed that the stabilised sand exhibited cohesion values of up to 990 kPa. The addition of polymer also increased the stiffness and the dilatant properties of the sand. The results of XRD and SEM indicated that the polymer filled the voids between the sand particles and thus improved the shear strength of the mixture.