A home owner invests a lot in the concrete around their home, and when a concrete sidewalk or concrete driveway has been poured, the last thing you want to see is a newly formed crack. Improper construction of expansion joints and control joints, or a poorly compacted ground before the concrete is poured, can lead the concrete to eventually fail.
If the concrete develops a crack, even the smallest crack can continue grow until the concrete sidewalk or driveway is a broken and cracked up mess. This can make a home seem neglected and in disrepair. Over time cracks can lead concrete to eventually buckle and heave, making it a hazard for people to walk on.
If you hire a concrete contractor to repair your concrete, he'll probably take the following approaches. First off cracks in concrete cannot be made to disappear completely. Cracks can be repaired though, and made to look much more attractive.