When precast concrete began gaining popularity in the years following World War II, septic tanks and a few other mainstay products dominated the industry. Mix designs and forms were rudimentary compared with those used today, so early experimentation with new products was limited by the available technology.
Since then, major advances such as self-consolidating concrete (SCC), a wide range of admixtures, and batching equipment that can control mix designs with incredible precision have revolutionized the industry. In addition, cranes and trucks have gotten larger, enabling plants to manufacture larger and heavier products, and custom forms have evolved to the point where an endless array of shapes, textures and aesthetics are possible.
All of these developments have led to a precast concrete industry that can manufacture virtually any structure an architect or engineer can design. Products that would have been unimaginable or simply unprofitable in the past – such as one-off pieces, custom changes to a standard product, elaborate and precise shapes, or architectural colors and textures – are now everyday realities.
For above-ground precast, this means products that belie the public perception of concrete as a gray, mundane building material. In the Winter 2011 issue of Precast Solutions,1 the “Precast by Design” article showcases custom veneers, finishes, colors, shapes and textures. Versatile form liners enable precast plants to mimic virtually any look from natural stone to wood grain. Add to that today’s advanced surface options and coloring systems, and almost any artistic aim is achievable.
Even underground products that spend their service life out of the public eye have changed dramatically. In the Fall 2011 issue of Precast Solutions, the three underground projects that won NPCA’s Creative Use of Precast (CUP) Awards perfectly illustrate this point.
Oldcastle Precast – San Diego manufactured massive caissons for a sensitive military project. Each base weighed in at a whopping 279,600 lbs, and all pieces were cast to exacting specifications. In New York, Garden State Precast’s Bronx River Combined Sewer Overflow project included three specially designed chambers that remove solids from the sewer’s outfall. And in Ohio, Norwalk Concrete Industries worked with Delta Engineers, located in Endwell, N.Y., to design a space- and time-saving precast concrete sluiceway that was originally slated to be cast-in-place concrete. This precast solution won over the project engineers. The sluiceway was part of Indianapolis’ reinvention of a three-block stretch of road into a pedestrian promenade, which became the hub of all street-level activity during Super Bowl XLVI.
While standard precast concrete is still the go-to solution for many construction projects, unique and innovative products have become more customary than custom for today’s advanced precast concrete industry.
1 Previous issues of Precast Solutions can be viewed online at http://precast.org/dev/magazines
Kirk Stelsel is NPCA’s director of Communication and associate editor for Precast Solutions magazine.