Evolution mechanism of the low-carbon MgO-based alkali-activated system under different heat-treatment conditions

Abstract

Magnesium silicate hydrate (M-S-H) gel is the main product of MgO-based alkali-activated system (MAAS). The molecular structure and phase changes of M-S-H gel at different temperatures were characterised. The results showed that the initial MgO:SiO₂ affected the Mg:Si ratio and the binding water content of M-S-H gel. With the decrease of Mg:Si ratio, the proportion of structural water in the gel decreases. Compared with structured water, the change of free water can more accurately characterise the content of M-S-H gel in the system. Below 600°C, the molecular structure and phase composition are relatively stable. When the temperature reached 1000°C, M-S-H gel transfers from amorphous phase to crystallized phase. The study characterised the evolution of MASS under different heat treatment conditions.

KEYWORDS:

• MgO-based alkali-activated system
• molecular structure
• evolution mechanism

Acknowledgements

This research was funded by the Natural Science Foundation of Hebei Province (NO. E2022209155), the Key Projects of Science, Technology to help the Economy in 2020 (NO. SQ2020YFF0426365), Science and Technology Research and Development Plan Project, Research on Key Technologies of Earthquake Recovery Function Structure (NO. 21422053283), Key R&D projects of North China University of Science and Technology (ZD-ST-202301).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Natural Science Foundation of Hebei Province: [Grant Number NO. E2022209155]; Science and Technology Research and Development Plan Project, Research on Key Technologies of Earthquake Recovery Function Structure: [Grant Number NO. 21422053283]; Key R&D projects of North China University of Science and Technology: [Grant Number NO. ZD-ST-202301]; the Key Projects of Science, Technology to help the Economy in 2020: [Grant Number NO. SQ2020YFF0426365].