EVALUATE THE DEPTH OF DESTROYED LAYER FOR REINFORCEMENT CONCRETE SAMPLES EXPOSED TO FIRE

Abstract

The behavior of reinforcement concrete slab dimension (500x500x150) mm and the cubes dimension (150 x 150 x 150 )mm samples are evaluated to the effect of fire according to the mix design concrete 40 Mpa compressive strength. The samples are exposited to the direct flame fire from down surface for three level of temperature degree (400,500 and 600) C° for one hour. After the samples are cooled to the normal degree of temperature, two non-distractive test are carried out: pulse velocity and shmidt hammer before and after the fire. Also the destroy layer depth is measured for the slab samples after the fire so the samples of cubes are prepared and tested after burning at the same circumstance which appear to slab reinforcement samples are purposed to found the change of the weight ,the compressive strength, pulse velocity and the number of rebound. The results indicate to (30%) reducing in compressive strength at level of temperature degree 400 C°, and (38%) reducing in compressive strength at level of temperature degree 500 C°, (48%) reducing in compressive strength at level of temperature degree 600 C°. The weight loss appear (0.5-0.55) %, (1.2-1.5) %, and (1.5-1.7) % for three level of temperature degree (400, 500 and 600) C°. Also, the atrsonic pulse velocity is decreased (62-68) %, (76-79) %, and (82-83) % for three level of temperature degree (400,500 and 600) C°.