Determination of the complete stress-strain response of concrete under uniaxial compression

Abstract

The characterization of the complete uniaxial compressive stress-strain curve of concrete is crucial for a more rational and reliable design of concrete structures. However, without intrinsic knowledge of the influence of different experimental control variables and the failure mechanisms of concrete, it is impossible to obtain a stable softening response in a test. This paper discusses the various aspects to be considered while performing the characterization, provides a comprehensive description of the different steps involved in the post-processing of the obtained experimental data. The influence of different test variables such as the type of contact, specimen size, rate of loading, the grade of concrete and fibre dosage on the compressive response is also elucidated. The complete stressstrain curves for different concretes have been obtained using the proposed procedure, which can serve as guidelines for such characterization. The brittleness of higher strength concrete is clearly manifested by a stress-strain curve that descends more sharply than those of conventional concretes. Further, it is seen that the incorporation of steel fibres mitigates the brittleness by improving the compressive toughness through bridging of the cracks and internal confinement.