When it comes to structural projects which require the bonding of concrete to concrete, easy and reliable adhesion is paramount. In this article, we’ll guide you through the step-by-step process of adhering one layer of concrete to another, ensuring a long-lasting bond between the two surfaces.

Materials and Tools You’ll Need:

1. New concrete mix

2. Concrete bonding adhesive

3. Wire brush or broom

4. Paintbrush or roller

5. Trowel

6. Water hose or bucket

Step 1: Clean the Original Concrete Surface

Before starting, ensure that the existing concrete surface is clean and free of any dirt, debris, oil, or grease to ensure proper adhesion of the new layer. You can use a wire brush or broom to remove loose particles from the surface. If necessary, use water and a mild detergent for stubborn stains.

Step 2: Pre-wet the Surface

Next, wet the original concrete surface with water using a hose or a bucket. This step is essential because dry concrete has a tendency to absorb moisture from fresh layers which could result in weak adhesion between both layers.

Step 3: Apply the Concrete Bonding Adhesive

Once the original surface is clean and wet, apply a layer of concrete bonding adhesive using a paintbrush or roller evenly on the entire surface you want to bond with new concrete. This adhesive acts as an intermediary in forming a strong bond between old and new layers.

Step 4: Prepare New Concrete Mix

While allowing enough time for your bonding adhesive to become tacky (follow manufacturer’s instructions), prepare your new concrete mix according to your project’s requirements.

Step 5: Pour and Spread the New Concrete

With your adhesive tacky and ready, pour a well-prepared fresh layer of concrete over it using appropriate safety measures. Ensure adequate coverage by spreading the new layer with the trowel or other recommended equipment in an even manner. It is essential to maintain consistency throughout this process, and do not leave large gaps or over-pour.

Step 6: Allow Time for Curing

Finally, give both concrete layers enough time to cure. Curing duration typically depends on factors like your concrete mix, environmental conditions, among other factors. However, it generally takes around 24 hours for initial curing and about 28 days for the concrete to reach its full strength.

Always remember to follow the manufacturer’s guidelines when using bonding adhesives and allow proper drying time for a strong and durable bond. With these steps, you’ll have a solid foundation upon which you can build the rest of your project with confidence.