Evolution of mechanical behaviour of mortar with re-saturation after drying
Résumé
This study deals with the effect of re-saturation after drying on the evolution of the mechanical behaviour of a standard mortar. Uniaxial and triaxial compression tests were performed according to the saturation state (saturated, dried in an oven at 60 °C until constant weight, re-saturated with water in different proportions). The results obtained show that even if the strength increases after oven-drying, the micro-cracking induced at the same time has an important influence on the evolution of the mechanical properties after re-saturation. The uniaxial and triaxial compressive strengths decrease regularly with re-saturation. The strength of vacuum re-saturated samples is lower than that of saturated samples (not subjected to drying) but the decrease is less marked in the case of triaxial deviatoric tests due to the presence of 15 MPa of confining pressure. Moreover, an additional decrease of Young’s modulus is observed in uniaxial compression after vacuum re-saturation while this modulus shows no variation in triaxial compression due to the presence of confining pressure. In addition, the elastic limit stress depends on the degree of re-saturation.