The drilling resistance test for the assessment of fire damaged concrete

In this paper, the evaluation of the drilling resistance is regarded as a method to ascertain the thermal damage undergone by concrete members after fire. Some preliminary tests on a good quality concrete were functional in defining the test procedure, the optimal bit diameter and the effect of the drilling thrust. A further study on uniformly damaged concrete cubes (ordinary and lightweight concretes – Rcm = 50 N/mm2) allowed to ascertain the sensitivity of the method. The reliability of this technique for the assessment of the damage depth within structural members exposed to fire has then been checked by testing some concrete panels exposed to marked temperature gradients. Finally, the viability of the method for in situ applications has been confirmed by testing the members of a precast RC structure which survived a real fire.