Concrete Overlay

Quick Overview

• Surface preparation is critical to any type of concrete repair. Prepare surface in accordance with ICRI Technical Guide No. 03730. It is more important to spend more time on surface preparation than on application of the repair mortar. Any structurally unsound concrete must be removed from the area to be repaired. Prepared surface must be dust-free and have sufficient profile to ensure adequate mechanical bond.


• If the concrete base for the repair material is sound, then all oil, curing compound, dirt, coatings or any other surface contamination must be removed.


• Products being applied in thicknesses greater then one inch, or where significant contamination exists require edge conditioning. Square cutting of the edges using a concrete saw is the most typical method. The smooth edge created by the saw cut should be roughened to ensure a mechanical bond at the edges.


• Protect area to be repaired from conditions that may cause early water loss; wind, low humidity, high temperature and direct sunlight.


• Set times will decrease as the product, air, substrate, and mixing liquid temperature increases and will increase as the temperature decreases.


• Do not bridge moving cracks. Maintain all existing joints or saw cut joint after application.


• Substrate must be saturated surface dry (SSD) and free of standing water.


• A bond coat slurry is recommended for achieving better bond with all repair materials. To achieve, mix a small amount of each batch mixed to a wetter consistency. Thoroughly scrub bond coat into the substrate with a clean, wet, stiff broom or brush immediately ahead of mortar placement. Do not allow bond coat to dry prior to placement of repair mortar.


• Make sure to follow all mixing instructions of the repair mortar. These will differ from product to product. Deviating on water to cement mix ratios can cause repair to delaminate prematurely or not fully cure.


• It is good concrete practice to cure all cement-based repair materials. The application of an ASTM C-309 SpecChem curing compound is recommended.


• For additional information on successful concrete repairs, consult International Concrete Repair Institute (ICRI) or American Concrete Institute (ACI) standards and guidelines or call SpecChem at 866-791-8700.