Evaluation of PIRs Post-Fire Pull-Out Strength in Concrete Exposed to ISO 834-1 Fire

International audiencePost-installed rebars (PIRs) using mortar can offer bond strength at ambient temperatureequal or higher to that of cast-in place rebars. However, high temperatures have the effect ofweakening the bond, typically governed by the chemical and physical properties of the mortar whichis often sensitive to temperature increase. Therefore, the behavior of PIRs in a fire situation becomesvulnerable. Moreover, after exposure of PIRs to high temperature, the heat transfer continues duringthe post-fire phase, which might endanger the construction after a fire event. In order to evaluate theevolution of the pull-out capacity during fire, Pinoteau et al. have developed the bond resistanceintegration method (Pinoteau’s RIM) to predict the bond resistance value of a rebar subjected tovarious temperatures in accordance with the fire exposure curves. Therefore, accurate temperatureprofiles during the post-fire phase are needed to ensure a correct calculation of the post-fire behaviorof the PIR connection. This paper presents 3D finite element thermal simulations of PIRs in concreteexposed to ISO 834-1 fire conditions then cooled with ambient air. Numerical thermal profiles arethen compared to the experimental results (i.e., post-fire pull-out tests). The proposed model providesguidelines for conducting numerical simulations to determine the thermal entry data necessary forpredicting thermal profiles in PIRs during heating and cooling phases. Then, the post-fire pull-outcapacity of PIRs in concrete is calculated using Pinoteau’s RIM, and compared to experimentalpost-fire pull-out results