Strength characteristics of cement-treated soil cured under extremely low temperatures

Abstract

This paper discusses the strength characteristics of cement-treated soil cured at extremely low temperatures ranging from 5°C to −20°C. When cement stabilisation is used to improve soft ground in cold regions with severe winter conditions, there is the possibility that the low curing temperature will hinder the solidification of cement-treated soil. To examine how extremely low curing temperatures affect the strength of cement-treated soil, a field study of cement stabilisation executed in the severe winter of Hokkaido, Japan, is presented in the first part of this paper. This study reveals that extremely low air temperatures prevented the shallow part of the cement-treated ground at the site from solidifying sufficiently. Then the influence of extremely low curing temperatures on the strength characteristics of cement-treated soil is discussed, based on the results of laboratory cement mixing and other tests. It is found that cement-treated soils cured at lower temperatures (−20°C, −5°C, 0°C, and 5°C) have lower unconfined compressive strengths (UCSs) than that cured at 20°C (a standard curing temperature according to the Japanese Geotechnical Society Standard). Cement-treated soils cured at −5°C and −20°C showed almost no gain in UCS. For cement-treated soils cured at 0°C or above, the UCS increased with an increase in maturity. Finally, based on the above experimental results, we proposed points to be noted in the construction of cement stabilisation in winter in cold regions.