Burning effect on physical characteristics of high-strength lightweight concrete T-beam repaired by SIFCON

The purpose of this research is to investigate the performance of high-strength lightweight cement concrete under extreme high temperature (fire) conditions. Lightweight expanded clay aggregate was used as aggregate for the reference mixture. An important difference from previous experiments was that the fire-damaged T-beams were covered with a layer of slurry infiltrated fiber concrete (SIFCON) with 15 and 30 mm thickness at a post-development stage. In addition to the standard tests, this study focused on the effects of the exposure of the beams to a burning flame for 30 min. The temperature distribution inside the T-beam's cross section was measured by installing thermocouples at strategic points. All materials used in this study were analyzed for their physical and chemical properties. Four concrete beam samples were examined in three phases (baseline “control,” fire test, and SIFCON reinforcing). Several parameters, including maximum load capacity and corresponding displacement “deflection,” ductility index, cracking load, initial and secant stiffness, and energy absorption, served as a basis for comparison between the samples. Compared to the damaged samples, the reinforced beams showed significant improvement in the experimental test results conducted in this study. Furthermore, they are as good as or better than the undamaged (reference) T-beams in all parameters except energy absorption. Further research and efforts are needed to resolve this problem.