Crack injection is a process of pumping slurry or resin into a vacuum to fill the cavities of a concrete slab. This is usually done to aid waterproofing or to prevent corrosion of concrete structures. Epoxy resins for crack injection come in a range of viscosities, from ultrafine to pasty, that are used to adapt to cracks of different widths. The main advantage of epoxy resins over other repair products is their high compressive strength, making them the only option for cracks that require structural repair.
Foundation Crack Expert Group offers two techniques that allow for fast and lasting repair of foundations. This reduces the chances of material coming out of an injected crack while it is still in liquid form, and even if something leaks out, the foam will fill the void. Epoxy injection resin is essentially a glue that, once cured, has a bonding strength that exceeds the strength of concrete; this makes epoxy ideal for repairing structural cracks. If the crack needs to be repaired only to prevent water leakage or if the crack is actively leaking, a polyurethane is usually the best choice.
These can also be purchased as crack repair kits that come with all the tools and supplies needed for the project. These fast-setting elastomeric foams are effective alternatives for applications involving only crack sealing (waterproofing) and no structural repair. It should be noted that the Province of Ontario Standard Specification OPSS 932 requires the use of high pressure for polyurethane crack injection at government construction sites. Injection is typically used in horizontal, vertical and aerial crevices where conventional repair methods are cost prohibitive.
Polyurethane crack injection kits are recommended for non-structural leaky cracks resulting from concrete shrinkage or minor settling, while epoxy injection kits are designed to treat more serious cracks that compromise the structural integrity of the wall. These products are ideal for repairing holes, chips and cracks in concrete, in both internal and external situations where heavy vehicle traffic is anticipated. At higher pressures, the liquid has enough force to overcome gravity and climb up the crack without filling the back, which is normally narrower than the front of the crack. When it comes to choosing between epoxy and polyurethane injection kits for crack repair, it's important to consider the characteristics of each product. Epoxy and polyurethane resins have different properties; accordingly, their use will vary depending on the characteristics of the crack of the base to be repaired.
The ARDEX injection range for concrete crack repair & uses a high-strength, fast-setting two-part system to repair concrete damage from fine cracks to structural repairs.