Will concrete sealer fill hairline cracks?
Ideally, the sealer has a low surface tension so it wets the concrete easily and a low viscosity. These two characteristics allow the liquid sealant to penetrate deep into the crack. Common topical concrete countertop sealers can be used, but getting them to penetrate and fill a hairline crack can be tricky.
What causes hairline cracks in concrete?
Probably the most common reason for early cracks in concrete is plastic shrinkage. When concrete is still in its plastic state (before hardening), it is full of water. This water takes up space and gives the slab a certain size. As the slab loses moisture during curing, it becomes a little smaller.
What to use to repair hairline cracks in concrete?
You can repair hairline cracks in concrete with a Portland cement and water-based grout. Add just enough water to the cement to form a thick paste. Dampen the old concrete along the hairline crack with water for several hours before adding grout.
Is it possible to repair a hairline crack?
Repairing hairline cracks can be tricky because making the cracks go away takes skill, patience, practice, and a good eye for color matching. One definition of a hairline crack is a crack that has not opened. This means that there is very little room to fill it with anything other than a very low viscosity liquid.
What’s the best way to seal a crack in concrete?
Add just enough water to the cement to form a thick paste. Dampen the old concrete along the hairline crack with water for several hours before adding grout. Wetting the concrete prevents it from drawing water from the grout, which will dry out the mix.
What causes hairline cracks in concrete in cantilever beams?
Multiple bending cracks in an overloaded cantilever beam. Hairline cracks often occur due to shrinkage, either from drying or heat. These types of cracks are more difficult to control. Because they usually occur near the surface, reinforcement does not help prevent them.
