The application of high strength concrete to reinforced concrete structures is very popular nowadays. This paper presents two main topics. In the first part of this paper, it is presented elasto-plastic properties of normal and high strength compressive concrete. It is known that actual behaviour of concrete is nonlinear. Design standard EN 1992-1-1 provides nonlinear stress-strain relation of compressive concrete for structural analysis. Expression to calculate this relation is given in standard. In this article, there are suggested coefficients which evaluate elasto-plastic behaviour of normal and high strength compressive concrete. Good correlation can be observed between stress-strain relation of compressive concrete given in standard EC2 and calculated relation using suggested elasto-plastic coefficients. In the second part of the paper, it is presented an overview of cracking moment calculations of reinforced concrete composite flexural members made from normal and high strength concrete and normal cross-section beams. These calculations were performed using existing design standard, technical construction regulation, structural building code (EN 1992-1-1, STR 2.05.05:2005, ACI 318) and layer method. New approximate values of elasto-plastic coefficients were suggested for tension concrete.
