Carbonation in lime-stabilized clays: mechanism, effects, and future prospects

Carbonation is an inevitable reaction during the construction and curing stages of lime-stabilized earthworks. Both bench-scale and field studies on lime stabilization recognize carbonation as a deleterious reaction due to the consumption of lime, which otherwise participates in pozzolanic reactions. Besides lime paucity, exposure of stabilized clays to carbon dioxide initiates the carbonation of cementitious phases. The stability of these phases is compromised and affects the cohesion among soil aggregates and the overall shear strength of stabilized clays. The mechanism of carbonation has been extensively investigated in the context of cement and concrete. However, limited efforts have been made to understand a similar phenomenon in lime- or cement-treated soils. Given this, a novel attempt is made to comprehend the carbonation reaction in lime-stabilized clays concerning the primary sources, fundamental mechanisms, significant factors, and deleterious effects. The historical developments in carbonation of lime-treated soils, microanalytical characterization, state-of-the-art, and prospects of future research opportunities in this field are also emphasized.