Keeping water from entering below your concrete slab can be a big help in preventing cracking and or failure of the concrete system. Over time you may have noticed in your driveway that you have cracks in the joints of the concrete, these joints are called control joints, and they are installed in hopes that if the system does crack it will crack in that joint, thereby controlling the way they crack looks. If control joints did not exist you would possibly have cracks that would go in all sorts of directions.
Cracks in these control joints can allow water to enter below the concrete slab and could cause erosion of the sub grade, and or water can collect in the sub grade, and cause the slab to move during freeze and thaw cycles. This movement is what will in the long run cause additional uncontrolled cracking and or failure of the concrete due to its tendency to sink as the sub grade erodes.
This problem can be corrected by the installation of a good quality caulk designed to adhere to concrete. The installation process includes cleaning and grinding the joint to give the surface an adhesion profile, a primer is then applied as needed, and the caulk is tooled into place.
In the event that you do have cracking that occurs in an area other than within the control joint of a concrete surface the process of repair is similar. The crack in this situation is routed out with a 1/4” tuck pointing grinding wheel, the edges are primed as needed, and a caulk is tooled into the 1/4” joint and finished flush with the concrete. This process is called routing and sealing.
In parking ramps, elevated slab cracks are often times repaired using the routing and sealing method, the main focus here is to prevent water from seeping into the crack and finding its way to the rebar. The water will cause the rebar to rust. Once the rebar is rusted, it will expand and cause failure of the concrete.
All of the caulking is subject to review once a year and caulk should be replaced as needed.