EFFECT OF SELF-HEALING ON THE CHLORIDE DIFFUSIVITY AT EARLY AGE
Résumé
The chloride diffusivity of cementitious materials significantly affects the durability of civil engineering structures (e.g. reinforced concrete buildings) and the waste containment matrices (e.g. sediments, radioactive waste). Its influence becomes greater when cracks appear due to restrained shrinkage. The results of an experimental campaign on the chloride diffusion characteristics of uncracked, cracked and self-healed mortar specimens are presented at several ages. The mortar compositions are characterized by several contents of blast-furnace slag. The diffusion characteristics are measured by means of accelerated migration tests and solutions titration with silver nitrate to determine the steady state stage and the effective diffusion coefficient. The cracking size is monitored using optical microscopy. Results clearly show that self-healing is a positive phenomenon that limits and reduces the crack size, therefore leading to a decrease of the diffusion coefficient. Moreover, the addition of blast-furnace slag intensifies this trend due to the slow hydration kinetics of this type of hydraulic binder.
Domaines
Génie civil
Origine : Fichiers produits par l'(les) auteur(s)
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