Imagine walking up the front walkway to your house at night and seeing the path lit up, not due to flood lights, but because the concrete illuminates light. Or imagine getting out of bed during the night, headed for the bathroom, with enough light emitting from the concrete floor for you to safely find your way. That's a small part of what Peter Tomé had in mind when he started his company Ambient Glow Technology (AGT), Toronto, in 2008. After he started experimenting with this idea in 2004, he gradually developed a marketable product. He liked the idea of producing light without using energy and states that his product can glow as long as 10 hours after being exposed to light for as little as 10 minutes.
Q.C. Concrete cast glowing aggregate into a bathroom countertop. At night, the pattern casts a visible glow.
It's all about the aggregate
It isn't the concrete that glows, but the aggregate seeded into the surface. Tomé discovered a way to mix photo-luminescent material in synthetic resin to make fine and coarse aggregate with a luminescent life cycle of about 15 years. He says that in the daylight the aggregates have a pale yellow appearance that's hardly noticeable. However in the dark dramatic changes occur—the aggregates radiate yellowish green, aqua blue, or sky blue color.
How to install it
Unless you are installing an epoxy or a thin cement-based terrazzo process, these phosphorescent aggregates work best when broadcast onto the surface of freshly placed concrete and left exposed on the surface. Tomé says any decorative finishes are possible, including stamped patterned concrete, exposed aggregate, or diamond-polished surfaces. Andy Miller, the owner of Q.C. Concrete, Amsterdam, N.Y., says he started installing Tomé's aggregates this year and has incorporated them in diamond-polished countertops, stamped concrete, exposed aggregate finishes, and artistically engraved applications. “The glow aggregates must be exposed on the surface so when we do a stamped concrete job for instance, we strike off the concrete, bullfloat it, and then broadcast the aggregate without finishing it into the surface. When the slab stiffens enough to stamp impressions, we lightly pound the aggregate into the surface to embed them.”
In direct light, the aggregates have a pale yellow appearance. At night, the aggregates give off green and blue illumination.
Credit: JOE NASVIK
Miller says he often mixes gradations ranging from sand to ½-inch stones to achieve good effects. For exposed aggregate jobs, he seeds glowing aggregates with other decorative stone because these aggregates are expensive. But he says that as little as one glowing aggregate per square foot provides a significant decorative effect. On a recent front walkway project, Miller and his crew spaced ½-inch aggregates 1 linear foot apart along each side of the walkway. “It provided a stunning effect,” Miller says. “It looked like an airport runway, easily providing enough light for people to find their way.”
A final thought
Decorative concrete is about being creative. Artistic contractors continually look for new materials and find interesting ways to use them. Miller says his company has been busy this year, partly because he offers clients more decorative possibilities than his competition. He started a relationship with Tomé's company and learned how to use these aggregates in creative ways because his competition wasn't doing it. Offering more to customers has helped him stay productive during these economic times.