WunderFixx is a one component concrete patching material used on til-up, precast and cast-in-place concrete. Formulated with Rapid Set non-shrink cement it is environmentally friendly and has the highest possible mold-resistance rating based on ASTM 3273. It also has excellent freeze/thaw performance, the company says. WunderFixx provides a low alkaline surface that reduces the susceptibility to color burnout and can be painted in three hours. WunderFixx sands to an ultra-smooth finish and uniform appearance.