Methodology of Studying Mechanical Properties of Reinforced Concrete

Abstract

In this paper, we study the mechanical properties of a complex composite material formed by steel and hardened concrete. A methodology of operative quality control of new credible concrete and reinforcement under both laboratory and field conditions, including determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load, is developed. A design of a mobile unit in which by means of reversal it is possible to change the load direction and to test the reinforced element of the established form under both tension and compression is presented. This reduces the nomenclature of test equipment and the number of forms for the manufacture of concrete samples. The values ​​of intrinsic stresses and the magnitude of deformations due to concrete shrinkage are determined by the forces of the crack formation in concrete when the joint operation of concrete and reinforcement is broken. An analytical dependence of the forces and deformations of a reinforced concrete sample with central reinforcement upon axial tension and compression taking into account deformations and stresses in the reinforcement and concrete on the concrete shrinkage is established. The results of experimental studies including concrete tensile diagrams and diagrams of the development of axial deformations with increasing load under central loading of reinforced elements are presented. A methodology of accounting for account stresses and strains due to concrete shrinkage in calculations of reinforced concrete structures is developed. The effectiveness of analytical expressions that establish a relationship between stresses and strains in material diagrams for calculations of reinforced concrete structures using a deformation model is estimated.