If you’re going to be laying new concrete over existing concrete or filling a crack in concrete, you’re going to need to use a concrete bonding adhesive. There are certain things that you need to keep in mind when getting ready to undertake a project such as this. Some of these special consideration items are listed in the paragraphs below.
Step 1 - Read the Instructions
Before beginning your concrete bonding project, be sure that you read completely through the supplied instructions sheets and that you fully understand them. Failure in this regard can cause your project to be a complete failure, meaning that you’ll have to undertake it all over again.
Step 2 - Remove All Contaminates
Sweep the area to be worked on completely. If this doesn’t remove all of the contaminants from the surface(s) you will be working on, you will need to try other methods. You may need to use some strong cleaners to remove any grease or caked-on dirt. If there are chunks of gum and/or other sticky substances, you may need to use a media blaster and then pressure wash to remove any dust and grit left by the media blasting. Make absolutely sure that nothing like mold, mildew, dust, or other contaminants are left on the surface being bonded to.
Step 3 - Mix
If the bonding adhesive you use requires mixing, make sure that you mix it thoroughly. If the instructions dictate that it be mixed at specific speeds or for a specific amount of time, don’t skimp and try to cut the mixing time short. If the instructions specify mixing for a specific amount of time, there is a very good reason for it. Not mixing enough may cause the concrete bonding adhesive that you use to not work properly.
Step 4 - Remove Loose Material
Inspect the surface the bonding adhesive agent will be used on. If there are loose pieces of concrete or chips, use a chisel to remove them prior to the application of the concrete bonding adhesive.
Step 5 - Use Bonding Agents and Concrete Cracks
If you’re going to be sealing cracks in concrete and the cracks are only hairline fractures, use a grinder with a masonry grinding wheel to widen them enough that you’ll be able to force the agent all the way into the crack and completely seal it. If the bonding agent doesn’t completely fill the crack, the bond will be incomplete and the fracture will continue to grow.
If any grinding is required, use a shop vacuum to pick up all of the dust generated by the grinding. Very small cracks should also be widened at the bottom so they are narrower at the top than at the bottom. This will cause the crack itself to help keep the concrete bonding adhesive agent in the crack.
Step 6 - Large Bonding Needs
If you are going to be filling a large crack, then you should use a thick gel-type bonding agent. If the crack being filled is a smaller crack, you will need to use a much thinner bonding agent to allow it to flow properly and completely fill any fissures in the sides of the crack.