Microstructure of Portland cement paste subjected to different CO2 concentrations and further water curing

Lu, Bao; He, Pingping; Liu, Jianhui; Peng, Ziyi; Song, Baixing; Xiang, Huimin

doi:10.1016/j.jcou.2021.101714

Cited by 57 publications

(8 citation statements)

References 44 publications

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“…In order to quantitatively analyze the CO 2 absorption capacity of the steel slag aggregates with TG/DSC, the results are shown in Figure 10. In Figure 10a, there are two distinct endothermic peaks, wherein the one within the temperature range of 400-450 °C can be ascribed to the decomposition of Ca(OH)2 and the endothermic peak in the temperature range of 600-750 °C resulted from the decomposition of CaCO3 [36,37]. The content of Ca(OH)2 and the endothermic peak of Ca(OH)2 decrease with the increase in carbonation temperature and carbonation time.…”

Section: Reaction Productsmentioning

confidence: 97%

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Ma,

Dai,

Jiang

et al. 2023

Materials

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Steel slag is the waste slag generated after steel smelting, which has cementitious activity. However, untreated steel slag can damage the integrity of steel slag concrete due to its harmful expansion. This study prepared porous aggregates by mixing powdered steel slag, fly ash, and cement and carbonated them with CO2 under high pressure conditions (0.2 MPa). The effect of carbonation on the performance of steel slag aggregate was studied using volume stability and crushing value. The effect of different carbonation conditions on the products was studied using X-ray diffraction (XRD) and thermogravimetric (TG) analyses, and the carbon sequestration efficiency of steel slag under different treatment methods was quantitatively evaluated. The research results indicate that untreated steel slag was almost completely destroyed and lost its strength after autoclave curing. With the increase in temperature and carbonation time, the performance of steel slag aggregate gradually improved and the pulverization rate, expansion rate, and crushing value gradually decreased. According to the experimental results of XRD and TG, it was found that the reaction between f-CaO (free CaO) and CO2 in steel slag generated CaCO3, filling the pores inside the aggregate, which was the internal reason for the improvement of aggregate performance. After comparison, the best carbonation method was maintained at 55 °C for 72 h. After carbonation, the steel slag aggregate had a pulverization rate of 2.4%, an expansion rate of 0.23%, a crushing value of 23%, and a carbon sequestration efficiency of 11.27% per unit weight of aggregate.

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Section: Reaction Productsmentioning

confidence: 97%

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Ma,

Dai,

Jiang

et al. 2023

Materials

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“…The cementitious carbonation process has been deeply investigated and the carbonation reactions are well known. However, carbonation rate is still unexplained due to many complex factors [32].…”

Section: Carbonation Reaction In Concretementioning

confidence: 99%

Carbonation Potential of Cementitious Structures in Service and Post-Demolition: A Review

Pederneiras¹,

Farinha²,

Veiga

2022

CivilEng

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The construction sector is responsible for a great environmental impact. The cement industry, which is included in this sector, emits about 650 to 800 kg of CO2 per each tonne of cement produced, being one of the most polluting industries in terms of greenhouse gas emissions. The cement manufacturing process releases about 7% of the total worldwide CO2 emissions. However, concrete and cement-based materials present CO2 uptake potential during their service life and post-demolition through carbonation processes. The carbonation reactions rate depends on several factors, namely type and content of cement, porosity of concrete, temperature, relative humidity and exposure conditions area. Therefore, to estimate the CO2 capture of concrete during its life cycle is not a straightforward calculation. Some studies have been developed using different methodologies in order to evaluate the CO2 potential of cementitious elements in service and post-demolition. This paper reviews the documented approaches that quantify the CO2 uptake of concrete over time, summarizing the assumptions adopted for each previous work. Overall, it was concluded that part of the CO2 emissions released during cement production are reabsorbed by concrete products during their life cycle, which partially offsets the environmental impact and reduces the CO2 footprint of the cement industry.

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“…Calcium carbonates also accelerate calcium silicate hydration and provide additional nucleation sites when water curing continues after early carbonation . Carbonated C–S–H seeds significantly improve cement hydration, attributed to their increased surface area .…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Carbon Footprint Reduction Potential of Cementitious Composites: CO₂ Sequestration in a Lime-Clay Binder Incorporating Medium-Grade Clay

Tahsin,

Ashraf

2024

ACS Sustainable Chem. Eng.

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This study evaluated the effects of CO 2 sequestration on the strength development, microstructural characteristics, and environmental footprint of a lime-clay binder for marine applications. This binder was prepared by mixing medium-grade clay (55.75% kaolin content) with lime and incorporating seawater for mixing and curing. The samples were cured in a CO 2 -containing chamber at an early stage to promote the carbonation reaction. Carbonation promoted silica polymerization, resulting in geopolymer gel and calcite formation in the matrix. The compressive strength of the carbonated composites was 36% higher than that of the noncarbonated counterpart after 28 days of curing, accompanied by a noticeable decline in the chloride-binding capacity. Sequestering CO 2 in medium-grade clay-based binders can reduce the global warming potential (GWP) by 47−66% compared to ordinary portland cement (OPC); additionally, the combined effect of clay-based mortar components decreased the GWP by up to 40% relative to the GWP of the OPC mortar. This work underscores the potential of CO 2 sequestration and seawater use in enhancing lime-clay binder systems while highlighting major environmental benefits.

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Microstructure of Portland cement paste subjected to different CO2 concentrations and further water curing

Cited by 57 publications

References 44 publications

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Carbonation Potential of Cementitious Structures in Service and Post-Demolition: A Review

Unveiling the Carbon Footprint Reduction Potential of Cementitious Composites: CO₂ Sequestration in a Lime-Clay Binder Incorporating Medium-Grade Clay

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Microstructure of Portland cement paste subjected to different CO2 concentrations and further water curing

Cited by 57 publications

References 44 publications

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Effect of Carbonation Treatment on the Properties of Steel Slag Aggregate

Carbonation Potential of Cementitious Structures in Service and Post-Demolition: A Review

Unveiling the Carbon Footprint Reduction Potential of Cementitious Composites: CO2 Sequestration in a Lime-Clay Binder Incorporating Medium-Grade Clay

Contact Info

Product

Resources

About

Unveiling the Carbon Footprint Reduction Potential of Cementitious Composites: CO₂ Sequestration in a Lime-Clay Binder Incorporating Medium-Grade Clay