Derivation of the complete stress – strain curves for concrete in compression

A closed-loop servo-controlled hydraulic testing machine can be used to generate experimentally the complete stress–strain curves for concrete in compression. However, the deformation readings obtained from the built-in low-voltage displacement transducers or other transducers placed between the machine platens include not only deformations of the concrete but also those due to machine flexibility and end-restraint of the specimen. In this paper, a correction factor is proposed to account for these effects. This requires the use of a compressometer fixed directly to the test specimen and transducers placed between the machine platens. More realistic stress–strain curves for concrete with cylinder (100 × 200mm) compressive strengths of up to 130 MPa have thus been obtained for the entire loading range.