Effect of acid rain on chemical and hydraulic properties of cement solidified/stabilized lead contaminated marine soft clay

Solidification/stabilization technique is widely used in remediation of heavy metals contaminated soils. Recently in China, deterioration of constructed infrastructures caused by acid rain is becoming a serious problem. This paper presents an investigation on influence of acid rain on the chemical and hydraulic properties of cement solidified/stabilized lead contaminated Lianyungang soft clay by batch leaching test, soaking test, and infiltration test. It is found that pH of acid rain, soaking time, infiltration volume of acid rain, and presence of sulfate in acid rain have significant influence on leaching of calcium and lead ions and hydraulic conductivity of the soils. The results show that with the decrease in pH of acid rain, leaching of calcium and lead ions from soils increased. The values of hydraulic conductivity decreased with infiltration time due to hydration reactions. Compared to the case of distilled water, infiltration of acid rain considerably suppressed the decrease in soil hydraulic conductivity due to the release of calcium ions and consequent retardation of hydration reactions. The soaking test results show that the presence of sulfate in the AAR could lead to more severe deterioration of the cement-based solidified lead contaminated soil in terms of change in pH of soaking solution. © 2012 American Society of Civil Engineers