effect of pore water quality on the mechanical behavior of an expansive soil during wetting and drying cycles

expansive soils are considered a worldwide problem as they cause extensive damage tocivil engineering structures. an important characteristic of expansive soils is theirsusceptibility to volume change due to the phenomenon of wetting and drying. this paperpresets the effect of pore water quality on the swelling and shrinkage behavior of anexpansive soil during wetting and drying cycles. thirty three soil samples were preparedthrough static compaction with various pore water qualities consisting of distilled water,sodium chloride (50g/lit) and calcium chloride (250gr/lit). wetting and drying cycleswere conducted on samples in a modified odometer apparatus under the surchargepressure of 10 kpa using distilled water as the reservoir fluid during the process ofwetting. results indicated that samples prepared with calcium chloride show moreswelling potential as compared with distilled water and sodium chloride. furthermore,swelling and shrinkage potential, specific volume and dry unit weight for soil samplesreach equilibrium after 5 cycles for distilled water and sodium chloride and while 3cycles for calcium chloride.