In July, I traveled once more to Grand Cayman to help my student Terry Wilson with a cool project. This was a 190 sq ft concrete bartop for the new Georgetown Yacht Club. It incorporated recycled glass (beer bottles), sliced coral and conch shells and glow in the dark aggregate!
The owner wanted to use sustainable materials, and he had heard several years ago about concrete countertops and how recycled glass can be incorporated into them. For the past 2 years, he has been saving every beer bottle he and his friends drank. He built his own concrete countertops for his office reception area and the washrooms for the marina. They look really great for a do-it-yourselfer! He showed me the countertops as an example of the look he was going for.
He wanted to use glow in the dark aggregate to create a special effect and also to cut down on lighting energy. I advised using Glow Stone from Ambient Glow Technology, as it has the best luminosity and is available in a variety of colors and sizes. He had obtained some samples from another company (at exorbitant prices!); you will see later the clear difference in luminosity.
The owner decided on 3/4″ Glow Stone in all 3 colors. The next order of business was to slice the coral and conch shells (easily available on the island) and to break up the beer bottles. There were 27 cases! Breaking them was not as easy as you might think. We had to crush them in small batches in a box, using a cast iron tamper.
We used beach sand from nearby, and for the pozzolan used a recycled glass pozzolan similar to VCAS. We also used every bag of white cement on the island! When Terry told me about the project, I told him to buy up every bag of white cement he could find, because I know from last summer how long it can take to get supplies onto the island.
Pour day went great. The pour was about 3 yards. We used ice to retard the mix. It’s always about 88 degrees (31 C) in Grand Cayman.
After screeding, we seeded the top with all the decorative aggregate and accents and screeded it in. This was a harsh mix! In the photo below, the section in the back has been floated, and the section in the front has not yet been.
The next day, we started grinding the concrete countertops to expose the recycled glass aggregate and other decorative features. At 1 day, the compressive strength was already 2150 PSI. The 3-day strength tested at 3730 PSI, and at 7 days it was 6750 PSI. Not the strongest concrete I’ve ever made, but as you know from other blog entries, compressive strength is not the most important property.
All the grinding, honing and polishing was very hard work, but it paid off. The client was thrilled, and the details in that bartop are amazing!
The Glow Stones looked amazing too. In the photo below, you can see some smaller stones from the client’s sample of the other “glowing” aggregate. They are much dimmer than the stones from Ambient Glow Technology!
In all, the project took about a week. The forms were built ahead of time. We poured on a Tuesday, spent Wednesday through Friday grinding, honing, grouting and polishing, and then Terry applied a simple penetrating sealer that weekend.
I can’t wait to go back and see the finished yacht club and have a beer at this bartop!
For even more photos, see the album on the CCI Facebook page.