Determination of stress–strain curves of concrete from flexure tests

A general procedure using a regression analysis approach has been developed to derive the stress–strain curves of concrete in the form of a polynomial expression from flexure tests. This procedure is applicable for different types of flexure test of concrete specimens, such as beams under pure flexure tests, columns under constant eccentric loading, and tests of C-shape specimens with neutral axis position controlled. In most cases, the derivation of the stress–strain curves of concrete using this procedure is simpler than others with the same approach. An experimental programme with different loading schemes was carried out. The stress–strain curves of concrete obtained from the test data using this procedure show good consistency. The results also show that it is possible to get the descending part of high-strength concrete further from the peak point using eccentric tests under normal testing conditions.