Clean the hole with a stiff fiber or wire brush.
Concrete pop out repair.
Using a cold chisel and a 3 pound sledgehammer undercut the hole by making the pop out wider at the bottom than at the top.
Chisel the bottom of the hole where the pop out occurred to make it level.
They ve been tackling these issues for a while and have some good solutions for both resurfacing and patching concrete.
Small pop outs leave holes up to 0 4 in.
You can patch the small holes by cleaning out the loose material and filling each one with a concrete patching material.
See the short video below.
Also known as rock pops they are small cone shaped pieces of a concrete surface that separate due to focused internal pressure.
10 mm in diameter.
Tap the chisel into the bottom of the hole sides to make a small ridge or undercut around the perimeter of the hole.
Repairing seasonal pop outs in stamped and colored concrete is easy with matchcrete clear.
Repair for small popouts use a rotary hammer drill and drill out the remaining deleterious substance and unsound concrete to create a hole with a minimum depth of inch.
For medium and large popouts use a hammer and chisel small chipping hammer or core drill to remove all remnants of deleterious substances and unsound concrete.
Come back after 24 hours and give the repairs a light sanding to blend them in.
It s possible the concrete was weak at this location because the concrete finishers used extra water when they tooled the control joint with the steel tool.
50 mm in diameter.
And large pop outs leave holes greater than 2 in.
Just add some powered pigment or grout to the clear matchcrete aliphatic polyurethane and you can match most any color.
Medium pop outs leave holes 0 4 to 2 in.
I would take a look at some of the products from quikrete.