Effect of aggregate on residual mechanical properties of heated ultra-high-strength concrete

When concrete structures are exposed to fire temperatures, their internal structure will change, and then the service life of the structure will decrease due to the deterioration of its strength and deformation capacity. The deterioration level will depend on the temperature reached, exposure time, mix proportions of the concrete, aggregate property and the material's own characteristics. This study was carried out to evaluate the influence of water to cement ratio, fine-grained aggregate to aggregate ratio and maximum size of aggregate on the thermal behavior of ultra-high-strength concrete. At room temperature and 500 degrees C the tests for compressive strength, static modulus of elasticity, ultrasonic pulse velocity, dynamic modulus of elasticity and weight loss were measured using the cylindrical specimens of empty set100 9 200 mm. The test data indicated that the fine-grained aggregate to aggregate ratio and the maximum size of aggregate have a significant influence on the residual mechanical properties of ultra-high strength concrete. And by measuring the ultrasonic pulse velocity of the ultra-high-strength concrete specimens, it was confirmed in this study that predicting the residual compressive strength is a distinct possibility.