Concrete is hard to beat as a basic material for all kinds of load-bearing surfaces, from driveways and sidewalks to floors, roads and airport runways. But concrete has two characteristics that can cause problems: It’s heavy and it can’t stretch.
The weight of a concrete slab can sometimes cause the soil beneath the slab to compress. When this happens, all or part of the concrete slab will sink down under its own weight, sometimes cracking in the process.
The cracking occurs because concrete isn’t a resilient material. If a slab is unevenly supported, it’s likely to crack because it can’t stretch or bend.
Instead of demolishing a sidewalk, roadway, or other concrete element that has settled, engineers can use different techniques to raise sunken concrete, while also strengthening and stabilizing the soil in the process.
These proven concrete lifting techniques are more affordable and less disruptive than total replacement, and can be used in the following applications:
By pumping a special mortar or an expanding foam beneath the slab, enough pressure is created to force the slab upwards. Once the mortar or polymer hardens, the repair is complete.
The PolyLEVEL™ System utilizes a high-strength polyurethane mixture to fill voids under concrete. With multiple formulas available, PolyLEVEL™ is able to fit the needs of any job, large or small.
PolyLEVEL™ is made up of a two-part urethane that expands into rigid foam that is used to fill voids, stabilize concrete, and lift concrete. The PolyLEVEL™ system has distinct advantages over other concrete remediation methods including: Light Weight - Material weighs approximately 4 pounds per cubic foot, which is significantly less than the 120 pounds per cubic foot of typical fill material. Since PolyLEVEL™ weighs as little as it does, there is almost no additional load added to the soil that is supporting the slab.
Many concrete lifting techniques involve pumping either expanding foam (known as polymer, urethane, or polyurethane) or a Portland cement-based mortar beneath the settled concrete until enough pressure is created to lift the concrete back to its proper orientation. Mud jacking or grout pumping is the older technique. Its main disadvantage is that the injected mortar must be allowed to cure before the repaired concrete can be used – a process that often takes several days. Polyurethane lifting, on the other hand, has no such lag time, since the injected polyurethane foam typically expands and hardens to its final form within a matter of hours.