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Due to the dilution-induced early-age strength reduction, the glass powder (GP) dosage used in concrete to replace ordinary Portland cement (OPC) is restricted. This study used carbonation curing on GP blended cement pastes to overcome this obstacle. The experimental investigations concluded that mutual improvements could be achieved, where, in comparison to the carbonated OPC batch, not only the compressive strength of 20% GP-incorporated batches was higher for both early-age (increment of 13.4%, 1-day strength of 55.4 MPa) and late-age (increment of 11.2%, 28 days strength of 62.4 MPa), but the carbon sequestration degree was also promoted. According to the characterizations of mineralogy, microstructure, and phase evolution of the blended cement paste subjecting to carbonation curing, the addition of 20% GP induced a higher carbonation degree, smaller calcite crystal size, refined pore structure, and reduced porosity than that of pure OPC control references. The sustainability assessments confirmed that carbonated GP blended cement is a cleaner alternative to OPC. • Paste properties were improved by synergizing glass powder and carbonation curing. • The optimal glass powder substitution ratio in OPC pastes was 20%. • Carbonated glass powder blended cement was sustainable as an alternative to OPC. [ABSTRACT FROM AUTHOR]

Low-carbon emission mortar samples were prepared using reactivated cementitious materials (RCMs) produced by calcinating hydrated cement paste with adjusted Ca/Si ratios. Carbonation curing was employed to enhance the cementing capacity of the RCMs and to sequestrate CO 2. The compressive strength, phase assemblage, microstructure, and environmental impacts of the mortars were analyzed. According to the results, the mortar sample produced with the RCM with a 10% addition of silica fume during calcination attained the highest compressive strength (35.3 MPa) after water curing, while higher silica contents were unfavorable because the low-lime calcium silicates that formed have limited water reactivity. Carbonation curing significantly promoted reactions of the RCMs and, thus, the compressive strength of the mortars compared to water curing. The amorphous and metastable calcium carbonates contributed more to the densification of the microstructure than the calcite. From the life cycle assessment, the RCM mortars had a significantly lower impact on global warming potential compared to Portland cement mortars. [Display omitted] [ABSTRACT FROM AUTHOR]