Influence of salinity exposure on the mechanical properties of cement-treated sand

Abstract

Cement-treated sand (CTS) is widely used to construct earth structures (dam, road sub-base, retaining wall etc.) due to economy and comparatively easier application. Nevertheless, the mechanical properties of CTS can be affected by the repetitive wetting–drying conditions during the design life. The situation may be exacerbated in a saline or coastal zone, as salinity has the potential to affect the strength of CTS. In this study, the effects of different exposure cycles – namely, air-drying and water submergence – on the mechanical behaviour of lightly CTS were studied at two different concentrations of salinity (0.1 M and 1.0 M sodium chloride (NaCl) solution). The unconfined compressive strength (UCS) was evaluated at the end of each cycle, and the results were compared with those under unweathered conditions. The UCS of CTS increased up to three cycles and reduced in the proceeding cycles irrespective of salinity concentrations. The maximum strength increase and decrease for specimens subjected to 0.1 M salinity were 19 and 25%, respectively, with respect to those for specimens under unweathered conditions. However, at the higher concentration (1 M), the strength increased about 12% and a 19% strength reduction was observed. In general, the CTS showed higher strength at 0.1 M salinity concentration compared with that at 1 M salinity concentration at a fixed cycle.