Experts often use epoxy for concrete repairs, especially if the repair needs to fix the concrete's structural integrity. For non-structural repairs, experts sometimes use polyurethane foams.
Concrete is useful largely due to its compressive strength, and epoxy used to repair concrete often has even greater compressive strength than the concrete itself. However, epoxy cures slowly, and it can be difficult to use if it can leak all the way through a crack. Polyurethane foams expand to fill cracks and begin to dry in minutes, so they're a popular option for restoring the look of concrete or for repairing concrete that is sufficiently strong even with a crack.