Study on the hydration mechanism of a hardened slag-based plugging agent activated by alkalis. (10th April 2019)

• Record Type: Journal Article
• Authors: Deng, Zhizhong; Zhou, Wen; Yue, Hong; Guo, Xiaoyang
• Is Part Of: Construction & building materials. Volume 203(2019)
• Page Start: 343
• Page End: 355
• Publication Date: 2019-04-10
• Subjects: Slag -- Microstructure -- Heat of hydration -- Transmission electron microscopy -- Nuclear magnetic resonance -- Photoelectron spectroscopy; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2019.01.015
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The microstructural changes of the plugging agent were analyzed during hydration. The reasons for the hardening effects of each activator were analyzed. The hydration heat of the reaction between the slag and activators was characterized. Abstract: To reduce the amount of time required for the formulation, adjustment, and application of a hardened plugging agent in the field, this study performed an in-depth analysis of the hydration mechanism of a slag-based plugging agent by heat of hydration characterization, transmission electron microscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The study shows that the NaOH activation of the slag-based plugging agent can produce an intermediate product Ca(OH)2 that is dissolved continuously to produce OH −, allowing the reaction to proceed continuously. Slag hardening occurs as follows: after the structure is destroyed, the recombination of groups changes their mutual spatial positions, thereby increasing the force between the groups and hardening the slurry. During the hydration process, a certain degree of substitution of Si by nonskeletal-element Al atoms in the slag occurs to form aluminosilicate, promoting the strength development of the slurry structure. The study results reveal a theoretical basis for shortening the time for the formulation and adjustment of the hardened slag-based plugging agent and provide new ideas for the development of new activators.