Understanding ettringite in cement-based materials and reasonable control

4. Outlook:

At present, the research on ettringite has been more in-depth, but there are still many uncertain factors. Considering the formation of ettringite plays an important role in cement-based materials, it is necessary to carry out further research on ettringite.

1) For the determination of ettringstone, we should not only care about the amount of ettringstone production, but also pay attention to the morphological characteristics of ettringstone, and even the distribution. For the determination of ettringite, the most commonly used is XRD analysis, but when the content of ettringite is small, the use of XRD detection is relatively difficult. The morphology and type of ettringite can be observed by SEM and EDS, but the amount of ettringite can not be determined. TGA can be used to quantitatively analyze the amount of ettringite produced, but its form and type cannot be determined. Therefore, a variety of methods should be used to accurately characterize the amount of ettringite production, morphological characteristics and distribution.

2) Control the formation of ettringite. It is advantageous to form ettringite in the plastic stage of cement-based materials, and the formation of appropriate ettringite after setting and hardening can help reduce shrinkage and improve the volume stability of cement-based materials. When using the expansion energy of ettringite, it is necessary to consider whether its expansion is within the design range, if it is still expanded after reaching the expectation, it will cause incalculable damage. Therefore, in practical engineering applications, ettringite should be reasonably regulated in the process of cement hydration and hardening according to needs, so that the formation time and amount of ettringite can reach the best, so as to give full play to the positive effect of ettringite.