Effect of MgO-Based Expansive Agent on the Cement-Based Mortar Behavior
Résumé
As shrinkage can affect the concrete durability, several solutions were designed to limit this deformation. One of them consists to add expansive agents like MgO-based products. The aim of the present research work is to better understand the effect of MgO-based expansive agent on the self-healing potential of cementitious materials. At 28 days old, Portland cement mortars with different contents of expansive agent (0%, 5% and 10%) are pre-cracked by means of splitting test and stored under water. Self-healing is monitored using 2D and 3D tests: optical microscope observations and water permeability measurements respectively. Mechanical resistances and deformations of the studied mortars are also monitored and their microstructures are characterized by means of thermogravimetric analysis. The results show that mortars containing MgO-based expansive agent present a better self-healing capacity. It can be due to its swelling capacity decreasing/deleting shrinkage deformations and the formation of supplementary products like brucite. © 2021, RILEM.