In mechanics of materials it is important to know the stress-strain relation of each material in order to understand their behaviour under different loads. Concrete is one of the most used materials in structural mechanics and they are always under axial loads. This work is implemented using one beam and the speckles created by its reflection. Strain field measurement with noninvasive techniques is needed in order to sense rough-like materials. We present an experimental approach that describes the mechanical behavior of structural materials under compression tests, which are done in a universal testing machine. In this work we show an evaluation of the in-field measurements obtained by digital image correlation allowing us to evaluate the heterogeneous strain evolution observed during these test.