Study of the behavior of reinforced concrete structures made from high-strength concrete during fire

Introduction. High-strength concrete has high mechanical strength and a number of other advantages, but is prone to explosive destruction during rapid high-temperature heating (in case of fire), which leads to a decrease in the cross-sections of reinforced concrete structures and premature occurrence of the fire resistance limit by loss of bearing capacity (R). The results of studies on the fire resistance of structures made of high-strength concrete are not available in the construction regulatory framework. The calculation method for assessing the fire resistance of structures made of high-strength concrete with fire testing has not been worked out too.Aim. Experimental study of fire resistance of reinforced concrete slab structures made of high-strength concrete of B60 and B100 classes, taking into account the influence of the process of explosive destruction of highstrength concrete in case of fire.Materials and methods. Concrete samples and full-scale slabs made of high-strength concrete with the addition of microsilica of B60 and B100 classes were subject to research. Full-scale solid-section slabs made of highstrength concrete of B60–B100 classes with steel reinforcement of A500C class were subject to fire tests. Based on the results of fire tests, the limits of fire resistance of full-scale slabs of high-strength concrete and the specifics of explosive destruction of high-strength concrete in a fire were determined.Results. The article presents the results of experimental studies and fire tests of the fire resistance of slab structures made of high-strength concrete.Conclusions. The effectiveness of research is determined by the development of a computational method for assessing fire resistance for structures made of highstrength concrete during design. Based on the results of the work, the need for further studies of the fire resistance of different types of structures made of high-strength concrete, with variations of high-strength concrete classes and types, depending on their material and quantitative composition, was revealed.