Effect of carbonation curing on sulfate resistance of cement-coal gangue paste

Qin, Ling; Gao, Xiaojian; Su, Anshuang; Li, Qiyan

doi:10.1016/j.jclepro.2020.123897

Cited by 80 publications

(36 citation statements)

References 58 publications

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“…The formation of Hc can be observed at 3 days, but as the hydration reaction proceeds, the Hc content decreases, and Mc is formed [52,53]. The presence of LF prevents the decomposition of ettringite to monosulfate, and the formation of Hc and Mc indirectly stabilizes ettringite [49,54]. Figure 13 shows the FTIR spectra of samples at 28 days.…”

Section: Xrdmentioning

confidence: 99%

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021

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This study examines the hydration–mechanical–autogenous shrinkage–durability–sustainability properties of ternary composites with limestone filler (LF) and ground-granulated blast furnace slag (BFS). Four mixtures were prepared with a water/binder ratio of 0.3 and different replacement ratios varying from 0 to 45%. Multiple experimental studies were performed at various ages. The experimental results are summarized as follows: (1) As the replacement levels increased, compressive strength and autogenous shrinkage (AS) decreased, and this relationship was linear. (2) As the replacement levels increased, cumulative hydration heat decreased. At the age of 3 and 7 days, there was a linear relationship between compressive strength and cumulative hydration heat. (3) Out of all mixtures, the ultrasonic pulse velocity (UPV) and electrical resistivity exhibited a rapid increase in the early stages and tended to slow down in the latter stages. There was a crossover of UPV among various specimens. In the later stages, the electrical resistivity of ternary composite specimens was higher than plain specimens. (4) X-ray diffraction (XRD) results showed that LF and BFS have a synergistic effect. (5) With increasing replacement ratios, the CO2 emissions per unit strength reduced, indicating the sustainability of ternary composites.

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Section: Xrdmentioning

confidence: 99%

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021

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“…For example, the impact of CO 2 curing on concrete lifespan would differ substantially between concrete with and without steel reinforcement, due to the heightened steel corrosion 48 caused by the CO 2 -induced pH reduction 49 . Additionally, geography specific factors such as sulfate-rich soils 50 , cold regions 39 , or acidic environments 22 can impact the durability of CCU concrete. The findings of this study can be further complemented by future research which quantifies the impact of variations in the lifetime and the geography specific factors on the net CO 2 benefit of CCU concrete.…”

Section: Resultsmentioning

confidence: 99%

Carbon dioxide utilization in concrete curing or mixing might not produce a net climate benefit

et al. 2021

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Carbon capture and utilization for concrete production (CCU concrete) is estimated to sequester 0.1 to 1.4 gigatons of carbon dioxide (CO2) by 2050. However, existing estimates do not account for the CO2 impact from the capture, transport and utilization of CO2, change in compressive strength in CCU concrete and uncertainty and variability in CCU concrete production processes. By accounting for these factors, we determine the net CO2 benefit when CCU concrete produced from CO2 curing and mixing substitutes for conventional concrete. The results demonstrate a higher likelihood of the net CO2 benefit of CCU concrete being negative i.e. there is a net increase in CO2 in 56 to 68 of 99 published experimental datasets depending on the CO2 source. Ensuring an increase in compressive strength from CO2 curing and mixing and decreasing the electricity used in CO2 curing are promising strategies to increase the net CO2 benefit from CCU concrete.

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“…Moreover, the increased dosage of mineral admixtures (fly ash and blast furnace slag) is able to increase the carbonation depth of concrete, due to the fact that the second hydration is improved by the addition of fly ash, thus consuming the amount of Ca(OH) 2 and increasing the carbonation of concrete. Finally, it can be concluded by comparing Figure 6a,b, the decreasing water-binder ratio can decrease the carbonation depth due to the improved compactness of concrete by reducing the water-binder [26,27]. Figure 7 shows the electric flux of concrete with different dosages of expansive agents.…”

Section: The Research Of Durabilitymentioning

confidence: 88%

Effect of Assembly Unit of Expansive Agents on the Mechanical Performance and Durability of Cement-Based Materials

et al. 2021

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This paper studies the influence of assembly unit of expansive agents (CaO and calcium sulphoaluminate) on the limited and free compressive strengths, the limited expansion rate, carbonation resistance, chloride ion penetration resistance and corrosion resistance of reinforcement concrete. The dosages of expansive agent were 0%, 3%, 6%, 9%, and 12% by the total amount of cementitious materials. Two kinds of mineral admixture (blast furnace slag and fly ash) were applied in this study. Results show that suitable dosage (lower than or equal to 9%) of double expansion agent with a large amount of mineral admixtures can improve the limited and free compressive strengths. However, when the dosage of the double expansion agent is higher than 9%, the addition of the double expansion agent leads to the reduction of limited and free compressive strengths. The variation of the limit expansion rate reaches the maximum value when the curing age is 14 days. The increasing addition of expansive agents and lower water-binder ratio demonstrate positive effect on the limited expansion rate. Concrete with 60% mineral admixtures (fly ash and ground granulated blast furnace slag) shows lower limited expansion rate and higher compressive strength than the concrete with 50% mineral admixtures. Finally, the incorporation of double expansion agent can improve the resistance to carbonation, chloride ion penetration resistance, anti-corrosion of steel bars and mechanical strengths (the limited and free compressive strengths).

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Effect of carbonation curing on sulfate resistance of cement-coal gangue paste

Cited by 80 publications

References 58 publications

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

Carbon dioxide utilization in concrete curing or mixing might not produce a net climate benefit

Effect of Assembly Unit of Expansive Agents on the Mechanical Performance and Durability of Cement-Based Materials

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