Hydraulic and strength properties of unexposed and freeze–thaw exposed cement-stabilized soils

Abstract

A total of 108 specimens were prepared to examine the hydraulic performance and strength performance of nine different cement-stabilized soils under unexposed and freeze–thaw exposed conditions. Specimens from each mix design were evaluated under two levels of curing conditions (i.e., immature versus mature). Hydraulic conductivity and unconfined compressive strength (UCS) measurements were performed to assess changes in the performance of specimens after 12 cycles of freezing at −10 ± 1 °C and thawing at 22 ± 1 °C. Measured mass losses of the specimens from a standard brushing test were also monitored at different freeze–thaw cycles, and results were compared with the changes in the hydraulic performance for each mix design. Hydraulic conductivity measurements on unexposed mature specimens showed that the lowest values likely occurred at water contents slightly wet of optimum water content (OWC). The UCS values showed a general decreasing trend with the increase in the water content for both immature and mature specimens under unexposed conditions. After freeze–thaw exposure, specimens showed minor reductions as well as increases of up to 5250 times in hydraulic conductivity values. Increases of up to 14% and reductions of up to 58% in compressive strength were also observed, compared with unexposed conditions. For most cases, mature specimens resulted in a higher degree of damage compared with immature specimens. Results from the brushing tests showed this test method is not a suitable indicator for predicting changes in the hydraulic performance of cement-stabilized soils. Hydraulic conductivity measurements after a period of post-exposure healing showed damaged specimens have some potential in recovering parts of the increased hydraulic conductivity value due to the healing process.