How Fluid Concrete Works

Using Fluid Concrete in Your Home

When most people think of projects involving concrete, they picture a parking lot -- perhaps one that stretches for what seems like miles outside a big box store. But fluid concrete is finding its way into some unexpected and less drab places -- specifically people's homes.

Given the self-leveling ability of fluid concrete, it would probably make a pretty good floor or patio slab in and around the home. However, given the added expense of the superplasticizers that thin the concrete, such a use probably wouldn't be cost effective. So, the most common use of fluid concrete in the home is for kitchen countertops.

That's right, kitchen countertops. You've probably seen them made from formica, tile and granite, but concrete countertops are becoming increasingly popular; they're ultra-durable and have a contemporary look. Concrete countertops are made with either fluid or stiff concrete. Stiff concrete has a very thick consistency -- almost like clay -- and typically its aggregate is sand. This means that it's very easy to apply to forms, but will wind up having little craters on the surface where air bubbles became trapped against the mold and couldn't escape through the thick puttylike concrete. Some people prefer this look -- which is reminiscent of stone -- but a smoother surface can be achieved by using fluid concrete.

When fluid concrete is used to make countertops, the aggregate is usually a bit coarser -- gravel or crushed stone -- and as with the mixes used in construction, it includes superplasticizers. The superplasticizers mean the countertop will have a smooth finish and it'll be strong and not as susceptible to shrinking and cracking. Still, this thin consistency means that forms must be more watertight than those used with stiff concrete. The fancier your kitchen is the more complicated things get. If you wanted, say, an integrated sink in your countertop, a stiff mixture could be pressed around a simple form because it holds itself in place, but a soupy fluid mixture requires a more complex form to support the concrete on all sides.

Concrete countertops can be installed in a couple of different ways. Craftsmen can fabricate them in a workshop then install them in your home, or they can be poured in place, right in your kitchen. Either way, the concrete will have to be reinforced with rebar or a wire mesh. You might assume that the final product will look grey and industrial, but that's not always true: Various pigments can be added during the mixing process to give the concrete a custom color to fit your specific tastes. When completed, these countertops can be a beautiful and long-lasting addition to your home.

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