Concrete joint sealing ensures all of the joints in a concrete pavement are sealed to prevent water entering below the concrete slabs, into the substructure of the pavement. Water infiltration will dramatically shorten the durability of the concrete, allowing it to soften and become unstable.
Not only does joint sealing prevent this happening, it also prevents the joints from filling up with non-compressible matter which would otherwise prevent joints from moving, shifting stresses to other points in the slab, and leading to irregular cracking.
Unsealed concrete joints may allow a concrete slab to sink and crack. If utilised early enough, joint sealing can defer (and even eliminate) the need for more expensive maintenance such as Slab Jacking/Stabilising (Mud Jacking, Lifting, Pressure Grouting) or, in worst case, the much more expensive cost of the complete reconstruction of the concrete slabs.
Simply put, the use of joint sealing on a concrete pavement, prior to an asphalt overlay, slows and greatly reduces reflective cracking on the new pavement layer.