Regardless of trade, preparation is often the single-most important step to ensure a professional installation. This is especially true when contractors are looking to install cement toppings. CTS Rapid Set concrete is specifically designed to harden and set within minutes of mixing, which can drastically increase contractor productivity. By setting rapidly, contractors can avoid the typical 30 day cure time many other concrete mixes require. Most CTS products allow contractors to return the next day to begin polishing or coating the placed slab. Preparation for CTS Rapid Set Products can be broken down into two steps: Surface Preparation and Priming the Surface.
Prepping the Substrate: The substrate should be clean, have an absorptive surface, be free of oil, curing compound, sealers, hardeners, or any other material that would inhibit adhesion. The surface should be mechanically prepped, with the preferred method being shot blasting or grinding. The surface of the concrete can be measured using the ICRI Concrete Surface Profile (CSP) of between 3-5. Shot Blasting is typically the easiest method for achieving this profile. See this chart below, which overviews surface profiles.
Priming the Substrate: Once shot blasting and/or grinding is complete, the substrate should be primed to allow for maximum adhesion when the CTS Rapid Set is placed. CTS Rapid Set offers both an acrylic primer, as well as a 2-part epoxy primer. The acrylic primer is mixed 1:1 with water and applied to the floor using a soft bristle broom at between 400-600 sq. ft. per gallon. A second coat of acrylic primer might be necessary depending on porosity of the slab.
The second option for priming the surface, is CTS TXP 2-part epoxy primer. TXP offers superior bond strength, one coat application, can withstand interior and exterior applications, and allows for placement of Rapid Set products in as little as 12 hours. The surface is prepared the same way, achieving a CSP of between 3-5. The floor is then cleaned using an auto scrubber. The TXP is mixed at 2 parts A to 1 Part B (2:1) using a slow speed drill mixer. The material is poured onto the substrate and applied using a notched squeegee and back-rolled using a 3/8″ nap roller at around 12 mils thick (0.3mm). After the coating is placed and still tacky, clean, dry silica sand should be broadcast to rejection using mesh #20-#30 sand. Once dry, the excess sand can be removed from the floor.
Once preparation and priming is complete, the floor is now ready for placement of CTS Rapid Set products. Runyon Surface Prep Carries a wide range of CTS products, as well as the tools used to install the products. Click here for our “Build Fast, Build to Last with Rapid Set Cement Products” article, outlining the process and products needed for TRU self-leveling projects.