Effect of aggregate on the fire resistance of concrete

Abstract

A variety of aggregates is used for concrete production. This article provides the analysis of the most frequent types of concrete aggregates, which are: gravel, dolomite, granite, and expanded clay. The fire alters the main feature of concrete – to resist compressive strength. When concrete is heated, both physical and chemical processes take place, and their negative results depend on the temperature level, speed of change and exposure duration, moisture content in concrete, its composition and structure, aggregates and characteristics of the contact area, production technology of structures, its size, shape of the cross section, load type, etc. The research of the analysis involved one-sided heating and volumetric heating according to the standard fire curve. Temperature measurements were carried out in different layers of concrete. The ultrasonic change in concrete specimens with different aggregates was measured too. Compressive strength decrease after heating is determined.