Fashions are cyclical. What was considered out of date a few years ago is now popular again. Just like clothing or music, trends in concrete are recurring. Exposed aggregate finishes are regaining popularity again, and for good reason. Here are a few reasons exposed aggregate concrete has seen this renewed interest.
The advent of retarding agents make exposed aggregate a more attractive design option. In the past, exposed aggregate finishes were achieved by broadcasting stone over wet concrete and pressing it in or by removing (mechanically or with acid) the surface of cured concrete. These were labor intensive and/or yielded inconsistent results. Chemical retarders eliminated these concerns. They prevented the cement reaction at the top of the slab and making it easier to remove the paste. This process was further simplified by retarders with set depths, such as Surface Deactivator.
Exposed aggregate is streamlined compared to other decorative finishes. But not just anyone can grab some cement and gravel at the local home improvement store and make a good looking exposed aggregate patio. Well-constructed exposed aggregate still requires an experienced concrete contractor. Expertise, experience, knowledge, and specialized tools are vital. When contrasted with stamped concrete and other finishes, exposed aggregate typically demands less time and labor. That brings a variety of benefits to both the contractor and the client.
Exposed aggregate upkeep is exceptionally simple. It just needs periodic cleaning and resealing as dictated by wear. That’s it. Over time, exposed aggregate shows less deterioration, too. The surface of concrete – often called the paste or cream – wears comparatively quickly which can lead to a ragged or dingy appearance. This is because the cream contains mostly fine sands and cement, and it lacks the structural integrity of the rest of the slab. By removing this cream ahead of time, and exposing aggregate, this wear is minimized and the concrete retains its original appearance longer.
The design variety for exposed aggregate finishes is surprisingly great. Appearance can be significantly varied just by choosing different exposure depths. Slight “acid wash” or “light sandblast” depths of 2 millimeters (or less) expose sands and small aggregates. This sleek, modern look that is very much en vogue. Heavier exposures of 3 millimeters or more that expose large aggregate and give the classic exposed aggregate look. At higher exposure levels, different color, shape, and types of aggregates also lend a unique appearance. Integral colors and stains can also be used to add more color or highlight, creating different effects.
One of the most attractive features of decorative concrete in general is its utility. This is especially true with exposed aggregate concrete. Concrete with an exposed aggregate finish can withstand high foot and vehicle traffic. It can also handle freeze-thaw climates, moisture, and other environmental threats just as well as regular concrete. Exposed aggregate is one of the best ways to add beauty without subtracting usability or functionality.
Exposed aggregate brings beauty and utility to a variety of situations. Perhaps one of the best and most common uses of exposed aggregate are pool decks and other anti-slip applications. Even at light exposure, these finishes help improve traction and reduce slip and fall hazards. Pretty much anywhere you can use concrete, an exposed aggregate finish is an option. Decorative bands and borders, precast panels, stencils, and even color hardeners can be used in conjunction with exposed aggregate.
Exposed aggregate is a classic finish with modern appeal. With the advent of modern chemical retarders, it is easier and more consistent than it ever has been. With a plethora of applications, exposed aggregate represents the past and future of decorative concrete.
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