Effect of Environment Acidity on Mechanical and Volumetric Properties of Expansive Soil of Subgrade

In this research, the effect of pH of the environment on the mechanical and volumetric properties of cement stabilized clay soils has been investigated through various tests in a laboratory scale. In this research, a problem-sensitive clay with chemical stabilization by cement in three short, medium and long term (3, 7 and 40 days) curing days under different pH conditions vary from acidic to alkaline with the pH of 4, 7 and 10 was tested in order to evaluate its mechanical and volumetric properties. Specifications for mechanical evaluation in this study included a test of density, single-axis bearing and California Bearing (CBR) test, which were used in different conditions in terms of the degree of acidity and curing days on specimens. The California Bearing Test (CBR) was also used to evaluate the volumetric properties. The results of this study show that soil improvement by cement increases mechanical strength and decreases the rate of soil swelling over time and curing days. However, the degree of acidity of the environment affects the chemical reactions of soil and cement, especially cement hydration, and causes changes in soil resistance and on the volume changes due to inflation. This effect depends on the pH and curing days.