Shayan Sheikhi Narani

Earthen materials are regaining popularity due to their intrinsic sustainability and recyclability. Depending on the mechanical properties of the local soil, the earthen construction techniques may require consuming binders such as lime or cement to reach the minimum engineering requirements. This paper deals with the questions regarding the influence of accelerated carbonation on stabilized rammed earth (RE) structures in terms of strength evolution, amount of CO 2 captured and safely sequestered, and the chemical and microstructural evolution of conventional and modern sustainable stabilizers in RE. The influence of different stabilizers, i.e., cement, lime, fly ash (FA) geopolymer, and ground granulated blast-furnace slag (GGBFS) geopolymer, is first evaluated on the mechanical strength of RE. The amount of CO 2 capture and sequestration through mineralization in stabilized RE as well as the thermal stability of mineral phases are investigated by thermogravimetric analysis on samples after exposure to accelerated carbonation. Different scenarios are also tested to explore the early-age strength development upon carbonation and evaluate the feasibility of carbonation curing for rapid strength development. The results showed rather high thermal stability of mineral phases in stabilized RE structures with an average CO 2 capture capacity of 0.60, 0.13, 0.09, and 0.04    mmol / g for cement-, GGBFS-, lime-, and FA-stabilized samples, respectively. Compressive strength tests showed a reduction in strength with carbonation, except for cement- and GGBFS-stabilized samples, which showed 6.2% and 47.8% improvement after 7 and 14 days, respectively. The results prove that although stabilized earthen materials can be used in construction, the mechanical strength variations due to carbonation should be considered in the design.