Effect of lithium salt and nano nucleating agent on early hydration of cement based materials

Wang, Jian; Qian, Chunxiang; Qu, Jun; Guo, Jingqiang

doi:10.1016/j.conbuildmat.2018.04.073

Cited by 29 publications

(17 citation statements)

References 15 publications

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“…It is seen that the early compressive strengths of 8 h and 24 h increased with the dosages of lithium compounds for all of samples. However, the larger content of Li 2 CO 3 , the lower compressive strength at 28 d, which was contrary to those of 8 h and 24 h. It is in accordance with the results in Wang's and Juilland's studies [19,20]. The early hydration acceleration caused by Li 2 CO 3 hindered the subsequent hydration of CSA cement minerals to a certain extent.…”

Section: Compressive Strengthsupporting

confidence: 88%

See 1 more Smart Citation

Influence of Different Lithium Compounds on Hydration and Mechanical Properties of Calcium Sulfoaluminate Cement

et al. 2020

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This work investigated the influence of three different lithium compounds, lithium carbonate (Li2CO3), lithium sulfate (Li2SO4) and lithium chloride (LiCl), on the hydration and mechanical properties of calcium sulfoaluminate (CSA) cement mixtures. Five concentrations of Li+, 0, 0.05, 0.11, 0.16 and 0.22 mmol/g of cement, were chosen, and then the proportions (by mass) of three lithium compounds were determined. Compressive strengths at 8 h, 24 h and 28 days were tested. Meanwhile, an early hydration heat test, thermogravimetric (TG) analysis, X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques were performed to study the influences of different lithium compounds on properties of CSA cement mixtures. The experimental results show that three lithium compounds can all accelerate the early hydration process of CSA cement. There is not a remarkable difference on the properties of CSA cement pastes with a different content of Li+. The anion of lithium compounds can also affect the properties of CSA cement pastes, the accelerating effects of LiCl and Li2SO4 are more significant than that of Li2CO3, but there is not a distinct difference between LiCl and Li2SO4.

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Section: Compressive Strengthsupporting

confidence: 88%

“…In recent years, special materials for emergency repairs are widely used in engineering applications, which require a high early strength [19]. In order to improve the early strength in the very short term, many researchers try to use an early strength agent during the application of cement-based materials.…”

Section: Introductionmentioning

confidence: 99%

Influence of Different Lithium Compounds on Hydration and Mechanical Properties of Calcium Sulfoaluminate Cement

et al. 2020

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“…However, if an excessive dosage of gypsum is used it could produce some negative effects such as a potential risk of crack formation in the cement matrix [ 23 ]. Furthermore, the presence of lithium ions efficiently facilitated the early hydration of CSA [ 24 ]. Lithium ions in lithium slag caused the disappearance of the induction period in CSA hydration, leading to the setting time being shortened and the early strength of the hardened paste being significantly increased [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Utilization of Carbide Slag by Wet Grinding as an Accelerator in Calcium Sulfoaluminate Cement

Tan

et al. 2020

Materials

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In this study, wet-ground carbide slag (i.e., WGCS) was utilized as an accelerator in calcium sulfoaluminate cement (CSA) for obtaining considerably faster setting processes for some special engineering processes such as plugging projects and rapid repair engineering. The WGCS–CSA system was designed, in which the replacement ratio of CSA by carbide slag was chosen as 4%, 8% and 12%. The setting time and compressive strength were measured, and the mechanism of the system hydration was studied in detail by means of calorimetry, XRD, thermogravimetry (TG) and SEM. The results showed that WGCS shortened the setting time of cement and significantly augmented the early strength. The addition of 8% of WGCS contributed to increasing the 2-h compressive strength from 4.2 MPa to 32.9 MPa. The decrease in the setting time and the increase in the initial strength were mainly attributed to the high initial pH value of the liquid phase and the high content of calcium ions in WGCS. Both these factors contributed to the ettringite formation and, at the same time, to the transformation of the morphology at a later time. Such results testify that WGCS can be used as an accelerator in the CSA system and also that it provides a novel approach to the reutilization of carbide slag.

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“…[12]. Lithium salts accelerate the hydration process of both Portland cement [4,13] and calcium sulfoaluminate cements [14]. Li 2 CO 3 addition decreases the decomposition temperature of CaCO 3 and lowers the formation temperature of β-C 2 S and C 3 S [15].…”

Section: Introductionmentioning

confidence: 99%

Early hydration of C2S doped with combination of S and Li

et al. 2020

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Production of low-energy cements would result in energy saving and lower CO 2 emissions related to reduced consumption of fuel and high-grade limestone as a raw material. Belite rich clinker, made more reactive by doping with combination of S and Li, could possibly be one of the low-energy alternatives for Portland cement clinker. Paper describes the preparation of doped belite and deals with its early hydration and reactivity. Belite rich clinkers were prepared in laboratory in high-temperature solid state synthesis. Pure substances were used for the preparation of raw meal and clinker. Early hydration heat flow development of cement pastes was monitored by isothermal calorimetry, changes in phase composition by "in situ" X-ray diffraction and TGA/DTA and microstructure by SEM-SE. Heat flow exotherms were correlated with quantified phase composition at given time. Intensity and position of main exothermic peak related to hydration of C 3 S is changing with increasing Li content. Doping of the C 2 S by the S or the combination of S and Li significantly increases the reactivity of the C 2 S-rich cement. The formation of C-S-H products is a continuous process that depends mainly on C 3 S during first 6 h and then is supported by slow reaction of β-C 2 S. The reactivity of C 2 S is affected by the timing of the hydration of other clinker phases. Two generations of portlandite formation detectable as a double endotherm on TGA/DTA can be attributed to hydration of C 3 S and β-C 2 S.

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Effect of lithium salt and nano nucleating agent on early hydration of cement based materials

Cited by 29 publications

References 15 publications

Influence of Different Lithium Compounds on Hydration and Mechanical Properties of Calcium Sulfoaluminate Cement

Influence of Different Lithium Compounds on Hydration and Mechanical Properties of Calcium Sulfoaluminate Cement

Utilization of Carbide Slag by Wet Grinding as an Accelerator in Calcium Sulfoaluminate Cement

Early hydration of C2S doped with combination of S and Li

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