After the exposition of concrete to fires, it is necessary to evaluate the residual strength of the concrete affected elements. Some methods to evaluate the residual capacity are based on the knowing of the depth of concrete affected by temperatures higher than 500ºC. The layer of concrete that have been exposed to temperatures upper than 500ºC must be not taken into account to do the structural recalculation. In the present work different physic-chemical parameters are used in order to define the alteration zones from the surface exposed to high temperature to the interior. Different layers of concrete exposed to fire are analyzed, from the surface, determining different physic-chemical parameters related with thermal behavior, using DTA-TG, and determining the main crystalline compounds, using XRD. Also, the microstructural analysis by BSE-EDX permits to corroborate the situation of concrete exposed to high temperature.

Trabajo presentado en el 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR), celebrado en Cape Town (Sudáfrica), del 2 al 5 de septiembre de 2012