The question arises again and again whether a not entirely successful fair-faced concrete cannot simply be improved a little with a concrete filler. You can read briefly and clearly here whether this is possible, which problems arise and what you should think about.
Optical effect when filling
Fair-faced concrete surfaces are intentionally not completely homogeneous, not completely even and in most cases do not have a completely uniform color. This is what defines the "concrete look ".
If you can see "pores" or craters in the exposed concrete, you can work with a concrete filler, but you shouldn't expect too much from the result. Punctual "corrections" to fair-faced concrete surfaces almost always remain conspicuous and visible and can ultimately make the appearance even worse than it was before.Tips & Tricks If you really want a completely uniform surface with a concrete look, simply consider doing without the exposed concrete wall and painting the concrete look. You can do this on any conventional wall. The result is impressive and you save the expensive exposed concrete.