How to Make Exposed Aggregate Concrete
Exposed aggregate concrete is not only great to look at and use as a design tool it also is great for walking on as it has a non slip aspect to it. If you are attempting to make exposed aggregate concrete, here are a few steps that can help you through the process with ease.
Step 1 - Pick Colors and Mix Concrete
The first thing that you will need to do is decide on a color or many colors that you want to use and then pick up the right mix for the color scheme that you want. Many times you can get a mix of colors or you have to take different colors and mix them together. In a wheel barrow or a bucket you can mix the concrete together based off of the instructions given with it. You want to make a similar consistency to cake batter. Continue to stir and mix the concrete until you have the right consistency and it is thick, but not too much that you can't easily pour it. Make sure to keep stirring so it does not start to harden on you.
Step 2 - Mold
Now you can spray the mold with non stick cooking spray. Then, you can pour the wet concrete slowly and evenly into the mold. It is important to make sure that you are tapping the mold on the side and bottom and even dropping it a few times to make sure that you are eliminating any air pockets that may have formed inside. If you do not do this you will wind up with unstable concrete as well as possibly uneven. Use the 2x4 to level the concrete on top and then use a putty knife to straighten out or shape any edges that may need to be molded or changed. You can start to do this right away or wait for it to harden a little and then shape it so that it holds. Now, let this sit for about seven hours. You will want to let it sit longer if the humidity is high. Up to a day is a good way to play it safe.
Step 3 - Scrub and Cover
Now that it is dry you can scrub the surface of it with a brush and then mist it and continue to do so. Then let this surface dry. You can cover it with a polyurethane sheet and then leave it to cure. This process should take about 3 days or so to complete. Then you can take the tile out of the mold carefully and let it sit for about 20 days before you actually put any pressure on it.
Now you can lay out and combine with others.