Dear colleague, there are tests that determine the penetration of some gases inside the pores of the concrete by mechanisms of visual observation. I recommend reading some texts on this topic, such as on carbonation fronts.

sulphate attack can be observed by cracks on concrete surface.

see https://theconstructor.org/concrete/in-situ-testing-of-concrete/15532/

Babar Ali yes, sulfate attack will leave a visible reaction front (for example, see attached from our lab). However, this will only give you a general idea of the depth of the sulfate front, and a more thorough characterization (e.g., using SEM-EDS, XRD, laser ablation with ICP-MS...) is usually important.