If there's a sidewalk or walkway on your property that has an uneven crack, it could be a serious tripping hazard. You wouldn't want someone to fall on the concrete and break a bone. Cracks that are level can be filled with patch material, but when one side of a crack is higher than the other, a different method is required. A concrete contractor can usually fix the problem without having to tear up the walkway. Here's one solution that might help when part of the concrete has heaved out of place:
Make Sure The Problem Isn't A Sunken Section
Uneven cracks are caused by one side sinking or the other side rising. The fixes are different, so the contractor has to assess the situation to make sure a heave is the problem. Heaving can be caused by frost or a tree limb; the result is one side that's too high so it has to be reduced. Filling it with patch fills the crack, but it doesn't eliminate the tripping hazard.
Saw Off Part Of The Elevated Concrete
The contractor may opt to saw off part of the heaved concrete so it doesn't stick up as high; this is done with a concrete saw. It's messy and noisy, but the work goes fairly fast. While the saw removes most of the elevated concrete, it doesn't make the surface nice and smooth so the trip hazard is completely gone -- that requires concrete grinding. If the crack elevation is small, the contractor may bypass using the saw and use a grinder to do the whole job.
Grind The Concrete To Make It Level
A concrete grinder is similar to a sander, except it's able to grind away thin layers of concrete as it's passed over the walkway. The grinder is moved over the entire crack to make the surface completely level and smooth. Once this is done, the concrete dust and rubble is removed and the walkway is safe once again. This process might be followed with filling the crack with patch material to close it.
If the concrete heaved due to a tree root, you might have ongoing problems. If so, talk to an arborist about ways to stop the root without harming the tree, if it's possible. It's always a good idea to have concrete problems repaired. Your city might give you a code violation for a crack in a driveway or sidewalk that poses a tripping hazard -- you might even be sued if someone trips and gets hurt. Avoid those unpleasant problems by having concrete repairs done when they're needed. For more information, you can contact companies like B M H Concrete Inc.