The Cracking Sensitivity of a Na-Geopolymer
Résumé
This research study aims to better understand the mechanical behavior of a Na-geopolymer used to immobilize the nuclear waste (MgZr alloys). Based on a large experimental campaign that has been carried out at LGCGM, the mechanical properties of Na-geopolymer are investigated as well as its cracking sensitivity at early age. This last depends on several parameters studied in the present project: tensile strength, Young’s modulus, and delayed deformations such as autogenous shrinkage and basic creep. All of these parameters are characterized experimentally under autogenous condition. These results obtained for a Na-Geopolymer are compared to those of a Portland cement-based mortar. From restrained ring tests, it appears that the cracking sensitivity is lower for Na-Geopolymer. This behavior is mainly due to a low Young’s modulus, a fast stabilization of autogenous shrinkage and a high creep capacity. © 2021, RILEM.