Cracks in concrete are not only unsightly, but they can also be susceptible to water ingress that can freeze and thaw, expand and contract repeatedly, making the crack worse. This type of water damage can destabilize the soil under the concrete, compounding the problem. Fortunately, in most cases, these are shrinkage cracks that formed when the concrete cured and are not indicative of a structural problem. In general, if the crack is stable and does not leak water, it does not indicate a structural problem.
However, if the crack is wider than a credit card and goes through the depth of concrete, it could be a sign of more serious issues. When concrete is still in its plastic state (before hardening), it is filled with water. As the water evaporates from the slab, it leaves large voids between the solid particles which make the concrete weaker and more prone to cracking. This type of cracking is known as “plastic shrinkage cracking” and occurs frequently.
As a general rule, any concrete slab longer than nine feet will crack. Tight cracks are common in concrete slabs and often go unnoticed until pointed out. In addition to traditional curing methods, concrete additives and curing compounds can help concrete cure faster and withstand the cold. If your concrete is a little older, a concrete repair professional can help you fix the cracks.
For a narrow crack like this, you can use a self-leveling concrete crack filler to seal the crack before painting or finishing the surface. Proper site preparation, quality mixing and good concrete finishing practices can go a long way in minimizing the occurrence of cracks and producing a more aesthetically pleasing concrete project. Read here about methods to cure concrete and understand how your contractor will cure concrete. A reputable local concrete driveway professional will know the best way to keep a concrete slab in good condition for optimal curing. In addition, concrete poured in mid-summer will have more cracks than concrete poured when it is colder. Since concrete cannot shrink around a corner, stress will cause the concrete to crack from the point of that corner.
Instead, cover the concrete with an insulating plastic sheet or even straw to trap moisture and help the concrete cure at an even rate. Yes, in about a month, fine cracks should disappear. While shrinkage cracks can appear on the surface within hours of pouring concrete, it takes a full month for new concrete to fully settle.
