Autor(a/res): Alex Neves Junior, Jo Dweck, Romildo Dias Toledo Filho e Brian R. Ellis.

Resumo: The concerns about greenhouse gas emissions have triggered investigations among the scientific community. The accelerated carbonation curing has been used as a tool to capture CO2 at early stages of cement-based material fabrication. In a previous study, the authors quantified the amount of CO2 captured in portland cement pastes by thermal analysis, at high relative humidity precure conditions. In the present work, the authors quantified the amount of CO2 captured in binary pastes derived from engineered cementitious composites (ECC), a family of composites worldwide used, whose one of their features is the precure at low relative humidity conditions. Two types of ECC pastes (1.2 and 2.2) were submitted to 4 h and 24 h of accelerated carbonation after 24 h of initial hydration. Using thermogravimetry and derivative thermogravimetry, the amounts of captured CO2 and respective carbonation degrees were quantified. The results showed that ECC paste 1.2 presented the highest values of captured CO2 and carbonation degree, considering all reactive components. In contrast, ECC paste 2.2 presented the highest values of these two parameters, when considering only portland cement as reactive component. For both pastes, the hydration degrees of the carbonated samples were higher than those of the non-carbonated references, indicating that in the used operating conditions, carbonation enhances ECC paste hydration.

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