Further responses of the bond in reinforced concrete to high temperatures

Tests were carried out to examine the effects of heat treatment upon the bond between concrete and steel by using direct displacement measurements and monitoring acoustic emission. A description of the experimental set-up has been given previously and, as before, it was used to test cylindrical pull-out specimens with an actual embedment length of 32 mm. The variables considered were type of bar (plain anddeformed bars of 16 mm diameter) and the effect of load cycling (for the deformed bar only) upon the bond after it has been subjected to heat treatment. The acoustic emission equipment was incorporated into the system to assess its validity in this type of testing and was used in all three of the different test situations investigated.