Impact of different hydrated cementitious phases on moisture-induced damage in lime-stabilised subgrade soils

Abstract

Durability is a major concern for all stabilised materials as it can reduce the structural capacity of pavement layers. One of the primary factors influencing the long-term performance of stabilised subgrade layers is moisture. The structural properties of these engineered materials starts to deteriorate with ingress of external water. The detrimental effect of soaking depends on the level of pozzolanic reaction achieved by the stabilised layer prior to water intrusion. Although the affinity for water is reduced after stabilisation, some amount of water is held within the matrix by the precipitated Calcium Silicate Hydrate (C-S-H) phases due to their inherent water adsorption capacity. The extent of damage in turn depends on the type and concentration of different cementitious phases due to the structural, compositional and morphological differences. This study tries to determine the type of hydrated cementitious phase that is more resilient to moisture-induced damage. Results indicate the presence of C-S-H II phase to be beneficial for durability of lime-treated soil when compared to C-S-H I phase.