STUDY ON INTERACTIONS BETWEEN ALITE-C&lt;sub&gt;3&lt;/sub&gt;A-GYPSUM HYDRATIONS

葵, 畠山; 豊春, 名和

doi:10.14250/cement.68.82

Cited by 2 publications

(1 citation statement)

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“…As is shown in Figure 5 a, the C 3 A reaction peak of PA4-450 almost overlapped with the silicate reaction peak, and the C 3 A reaction peak of PA9-450 appeared on the left side of the silicate reaction peak, showing that the AS accelerator could promote the C 3 A reaction. It is that the low gypsum content of cement accelerates the C 3 A reaction [ 42 , 43 ], which is the high final C 3 A/SO 3 ratio [ 31 ]. Considering that the AS accelerator reacts rapidly with gypsum to form ettringite, cement paste samples with different doses of the accelerator will have a different final C 3 A/SO 3 ratio.…”

Section: Resultsmentioning

confidence: 99%

Experiment Study on the Effect of Aluminum Sulfate-Based Alkali-Free Accelerator and the w/c on Cement Hydration and Leaching

Ling

Jie

et al. 2023

Materials

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The alkali-free accelerator based on aluminum sulfate is widely used in shotcrete in tunnels. Long-term Ca-leaching of shotcrete may adversely affect the tunnels in a water-rich mountain. It is necessary to examine further the impact of the AS accelerator and w/c on cement hydration and leaching. In this study, all the cement pastes were cured in the environment with R.H. > 95% and 20 ± 1 °C for 60 days and leached in a running water test with 6 M NH4Cl at 1 cm/s. The hydration kinetics was characterized by isothermal calorimetry. Additionally, the microstructural and mineralogical alterations were characterized by XRD, SEM, MIP, and N2 absorption. The results show that (1) the AS accelerator affected the hydration kinetics of cement by stimulating early hydration and delaying the late silicate hydration, resulting in AS-accelerated cement pastes with rougher pore structure. As a result, the higher the dose of AS accelerator, the faster the cement pastes will leach. (2) Hydration kinetics of the accelerated cement are not affected by the w/c. The AS-accelerated cement pastes with lower w/c have a denser pore structure. So, the reduction in the w/c contributes to leaching resistance.

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Section: Resultsmentioning

confidence: 99%