CONSTITUTIVE AND STRUCTURAL BEHAVIOR OF SILICEOUS HIGH-STRENGTH CONCRETES AFTER A THERMAL CYCLE AT HIGH TEMPERATURE

摘要

The fast-growing use of high-strength concretes in a variety of structures requires knowledge of their behavior in extreme environmental conditions, such as after a sufficiently long period at high temperatures (steady state). Thinking of increasing temperature levels, one of the open questions is to what extent the increasing concrete toughness offsets its decreasing strength and stiffness in ensuring a ductile structural behavior. Within this context, some results of a research project regarding the residual mechanical behavior of deep beams and circular slabs (after a single cycle at 105, 250 and 400 deg C) are presented. As a preliminary, the behavior in compression and tension of two siliceous high-strength concretes (f_c = 72 and 95 MPa) is recalled.