Experimental study of possible ways to increase cohesion strength in the 'steel-concrete' contact zone under displacement conditions

摘要

Traditionally, to increase bond strength between steel reinforcement and concrete, flexible fluted reinforcement are used. In modern tower buildings, to increase load-carrying power high-loaded columns of lower floors, rigid reinforcement (I-shaped, U- beam or another) without roughening is used along with flexible reinforcement. The problem which arises is that of reliable cohesion between rigid reinforcement and concrete to ensure their collaboration in the structure. The state of stress in the contact "steel-concrete" zones is highly diverse. It depends on a number of factors and varies a lot in the course of loading. Analytical solutions may be obtained just for a very limited class of contact problems. To apply numerical methods and state-of-the-art software packages, it is necessary to know the parameters of the initial bonds' default (separation) - loading and displacement, which depend on both mechanical adhesion and chemical interaction of materials in the contact zone. For this purpose, three classes of concrete and two kinds of fibrous concrete have been subjected to experimental testing. Under consideration were the ways of increasing cohesion strength in the contact "steel-concrete" zone in case of displacement by introducing additional coupling elements onto rigid reinforcement and applying epoxy resin coating onto metal.