The influence of different kinds of weak acid salts on the macro-performance, micro-structure, and hydration mechanism of the supersulfated cement

Xing, Jiarui; Zhou, Yang; Peng, Zechuan; Wang, Jiawei; Jin, Yanji; Jin, Ming

doi:10.1016/j.jobe.2023.105937

Cited by 13 publications

(3 citation statements)

References 34 publications

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“…Generally speaking, the weight loss peak of portlandite appears at about 400-500 • C, but no corresponding peak can be observed for any of the mixtures. The peak at 700 • C is caused by the decarbonization of CaCO 3 [62]. The weight loss peak of CaCO 3 corresponding to all mixtures is not apparent, indicating that the carbonization of the hardened pastes is not severe, which is also in good agreement with the result obtained by QXRD.…”

Section: Tgasupporting

confidence: 87%

Study on Sustainable Application of Low-Carbon Supersulfated Cement with Alkanolamines

Zhou,

Jin,

et al. 2024

Sustainability

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As an environmentally friendly cement material in green buildings, due to its low contribution to air pollution and its substantial use of solid waste, supersulfated cement (SSC) has been extensively studied. However, the low early strength of sustainably utilized SSC needs to be addressed. In order to use SSC to achieve great reductions in energy consumption during industrial production, the effects of triethanolamine (TEA), diethanolisopropanolamine (DEIPA) and triisopropanolamine (TIPA) (with dosages ranging from 0.02% to 0.08%) on the strength and hydration of SSC were studied, and the underlying mechanism was analyzed by TGA, XRD and SEM. The results show that TEA and DEIPA significantly improve the 3-day and 28-day strength of SSC. The former is better at low dosages, while the latter is more suitable for high dosages. TIPA also enhances the 3-day strength of SSC, but it is not as good as the other two alkanolamines. The chelation of alkanolamine with Al3+ ions plays an important role in the strength development of SSC, which accelerates the decomposition of slag and the formation of ettringite. In summary, adding alkanolamines to low-carbon cement systems with a high proportion of industrial by-products such as SSC is a potential and effective solution. In addition, alkanolamines can be used as a strength promoter for most low-carbon blends, which fully utilize solid waste.

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Section: Tgasupporting

confidence: 87%

Study on Sustainable Application of Low-Carbon Supersulfated Cement with Alkanolamines

Zhou,

Jin,

et al. 2024

Sustainability

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“…An alkaline compound, such as KOH, was incorporated into SSC to enhance its early strength [20,22]. SSCs with a low-content KOH activator exhibited lower hydration kinetics, and their early strength development was also relatively slow [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of Calcium Aluminate and Carbide Slag on Mechanical Property and Hydration Mechanism of Supersulfated Cement

Qi,

Zhang,

Sun

2024

Buildings

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Supersulfated cement (SSC), a low-carbon, energy-efficient, eco-friendly cementitious material, is mainly made from industrial byproducts. However, SSC’s slow early strength development leads to inadequate initial hardening and reduced durability, which restricts its practical application. This study investigated the potential enhancement of SSC by incorporating calcium aluminate (CA) and carbide slag (CS) alongside anhydrite as activators to address its slow early strength development. The effects of varying CA and CS proportions on the mechanical property and hydration mechanism of CA-CS-SSC were examined. Results indicate that employing 1% CA and 4% CS as alkaline activators effectively activates slag hydration in the 1CA-4CS-SSC, achieving a compressive strength of 9.7 MPa at 1 day. Despite the limited improvement in early compressive strength of other mixtures with higher CA and lower CS proportions in the CA-CS-SSC system, all mixtures exhibited enhanced compressive strength during long-term hydration. After 90 days, ettringite formation in the CA-CS-SSC system decelerated, whereas anhydrite remained. Concurrently, the formation of C-S-H continued to increase, promoting late compressive strength. The mechanism for enhancing the early compressive strength of the CA-CS-SSC system is attributed to the swift hydration of CA with anhydrite, dissolution of fine slag particles, and reaction with anhydrite under conditions with suitable alkali content to augment the ettringite production. This process also generates a C-S-H and OH-hydrotalcite to fill the void in the skeleton structure formed by ettringite, resulting in a dense microstructure that improves early compressive strength.

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“…A high molar concentration of NaOH facilitates C-A-S-H gel formation, but its highly alkaline conditions raise safety, energy consumption, and carbon emission concerns, contradicting SSC's low-carbon objectives. Therefore, adjusting the pore solution pH emerges as a key strategy to optimize SSC performance, where using sodium lactate and low-concentration sodium citrate as alkaline activators can promote ettringite and C-S-H gel formation, maintaining SSC strength stability (Xing et al, 2023). The chelation effect of sodium lactate on the slag surface accelerates its dissolution rate, improving SSC's mechanical properties (Masoudi and Hooton, 2020;Zhou et al, 2021;Peng et al, 2022).…”

mentioning

confidence: 99%

Mechanical properties and hydration mechanism of super-sulfated cement prepared with ordinary Portland cement, carbide slag, and sodium silicate

Qi,

Zhang,

Sun

2024

Front. Mater.

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Super-sulfated cement (SSC) is known for its low-carbon footprint, energy efficiency, and eco-friendliness (mainly derived from industrial by-products) with promising applications. However, SSC’s slow early strength development results in inadequate initial hardening, compromising its durability and limiting its use in practical engineering projects. This study aims to enhance SSC’s early performance by incorporating ordinary Portland cement (OPC), carbide slag (CS), and sodium silicate as alkaline activators alongside anhydrite. The effects of varying proportions of OPC, CS, and sodium silicate on SSC’s compressive strength and hydration mechanism have been investigated experimentally in this study. Results show that using 2% OPC, 2% CS, and 1% sodium silicate as alkaline activators effectively activates slag hydration in SSC-2, achieving a compressive strength of 9.6 MPa at 1 day of hydration. As hydration progresses, SSC’s compressive strength continues to increase. In the early hydration stage, OPC and CS create an alkaline environment for SSC, facilitating rapid slag reaction with anhydrite and sodium silicate, resulting in ettringite and C–S–H formation. Simultaneously, slag hydration produces C–S–H and OH-hydrotalcite, filling voids in the ettringite-formed skeleton structure, leading to a denser microstructure and significantly enhancing SSC’s early compressive strength. From 28 to 90 days of hydration, the ettringite formation rate decreases in the SSC system, but some anhydrite remains, while C–S–H production continues to rise, further enhancing late-stage compressive strength.

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The influence of different kinds of weak acid salts on the macro-performance, micro-structure, and hydration mechanism of the supersulfated cement

Cited by 13 publications

References 34 publications

Study on Sustainable Application of Low-Carbon Supersulfated Cement with Alkanolamines

Study on Sustainable Application of Low-Carbon Supersulfated Cement with Alkanolamines

Effect of Calcium Aluminate and Carbide Slag on Mechanical Property and Hydration Mechanism of Supersulfated Cement

Mechanical properties and hydration mechanism of super-sulfated cement prepared with ordinary Portland cement, carbide slag, and sodium silicate

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