Examining freeze/thaw cycling and its impact on the hydrualic conductivity of cement-treated silty sand

Abstract

Cement-based solidification/stabilization (s/s) is a remediation technology that has been widely used for treatment of a range of contaminants. Currently there is limited published data on changes in hydraulic performance of cement-treated materials subjected to cycles of freezing/thawing (f/t). Fourteen sets of tests were performed to examine the influence of factors such as number of f/t cycles, freezing temperature, curing time, and mix design on hydraulic conductivity and unconfined compressive strength (UCS) of a cement-treated silty sand. Results showed an increase of up to three orders of magnitude in hydraulic conductivity as well as decreases in UCS values after exposure to four to twelve f/t cycles. Analysis of variance (ANOVA) performed on the results of a factorial experiment considering the effect of freezing temperature, curing time, and number 22 of f/t cycles showed that all of these factors are significant in affecting the measured changes in the hydraulic conductivity and UCS values. Monitoring of damage using the impact resonance method showed that changes in the resonant frequency of specimens was consistent with changes in hydraulic conductivity and UCS after f/t exposure and also allowed monitoring of damage for intermediate cycles with minimal effort.