| A series of Direct Shear (ASTM-D3080), XRD and SEM tests were conducted on several chemically treated, identically prepared, specimens of high-plasticity, sulfate-rich clay from southern Arlington, Texas. Test results were used to assess the influence of cyclic wetting-drying on shear strength parameters, chemical composition and micro-fabric of both control and treated soils. Specimens were prepared from control soil and treated with one stabilizer type at two dosages, subjected to incremental number of wetting-drying cycles (0--32 cycles) and tested at three normal pressures of 1, 2 and 4 ksf during DS testing.;Sulfate resistant type V cement was used as chemical stabilizer. Soil properties investigated under cyclic wetting-drying include cohesion, friction angle, mineral composition, micro-fabric and pH. Identically prepared specimens were subjected to 12 hrs of wetting at room temperature (70°--75°F) and 12 hrs of drying at 140°F, which constitutes one w-d cycle.;The shear strength of control and 5% cement treated soils decrease with increase in number of w-d cycles, where as for 10% cement treated soil there is an increment. There are no significant changes in chemical composition and micro-fabric of the clay particles in neither control soil nor treated soil under cyclic w-d. |
