Written in Stone
- By Amy Milshtein
- February 1st, 2010
“I can’t think of a single downside to using precast concrete for any campus landscape project,” said Todd Ebbert, general manager, US Concrete Precast Group, Southern California Division. While Mr. Ebbert is undoubtedly biased, he has a point. Concrete is sustainable and durable, and precast offers some unique advantages. College Planning & Management takes a look at this product to see if it fits the mold of your next project.
Concrete — A Solid History
Concrete is used more than any other man-made material in the world. According to Wikipedia, as of 2006, about 7.5 cubic kilometers of concrete are made each year — more than one cubic meter for every person on Earth. The material has been used in some form since the Romans, and many of those early structures survive today. However, the secret to concrete was lost until 1756, when British engineer John Smeaton pioneered the use of hydraulic lime in concrete.
Portland cement was first used in concrete in the early 1840s. Considered to be the most common type of cement in use today, Portland cement is utilized for all sorts of building projects. The cement is used as an ingredient in materials used for sidewalks, buildings, and as a binder between other substances, such as stone or brick. The basic formula for Portland cement was first identified by that name in the early 19th century. Today concrete is used in a variety of infrastructure, from roads and buildings to decorative countertops and floors. It can be colored, molded, and stamped. It can also be polished and engraved. Existing concrete can be remolded to look like tile, flagstone, or cobblestone.
“Throw any idea at us and our design team can accommodate you,” said Ebbert. In fact, his team just won an award for creating the world’s longest stress ribbon bridge — the Lake Hodges Bicycle/Pedestrian Bridge in San Diego. Only the sixth such bridge to be built in the U.S., the design was chosen because it would have the least environmental impact.
Concrete — A Green Choice
While your college probably doesn’t need something as substantial as a stress ribbon bridge, you might use some of the same criteria for choosing the material. All concrete remains a sustainable choice. “We use fly ash, which is a byproduct of the coal industry,” reported Ebbert. “If we didn’t, it would end up in the landfill.” “Using fly ash earns your product LEED points,” continued Ken O’Neill, vice president of marketing, Oldcastle Architectural Products Group. Although, he cautions that the EPA is looking at fly ash as a possible hazardous waste because of a 2008 spill by the Tennessee Valley Authority.
While the fly ash issue remains unresolved, the end product continues to be solid — meaning it will stay out of the landfill longer. “We warrantee our products for at least 25 years,” said Ebbert. “Its structural integrity easily outlasts wood or fiberglass, and it is not susceptible to ultraviolet light.”
Precast pavers — like those found in a walkway, crosswalk, parking lot, or bus loading zone — can also help purify water. “Permeable pavers control storm water runoff by allowing water to pass through through base and sub-base materials,” said O’Neill. “This acts as a filter and keeps oil, fuels, heavy metals, and litter from running into the storm drain. In the next few years, legislation will demand that more projects are completed with permeable surfaces.”
While all concrete offers the same durability, precast lends another special environmental caché. Pouring and molding on site means roping off an area with safety fencing and bringing in excavators and pouring trucks, all of which impact the surroundings. This isn’t an option for many projects. The Lake Hodges project site, for instance, is home to endangered birds. Precasting meant the bridge could be installed with the least environmental impact. “It’s also a safety issue,” continued Ebbert. “Diverting traffic patterns, fencing off an area, and increasing traffic all add stress to a campus.”
Concrete — A Classical Choice
At University of California–Berkeley, precast concrete elements are an integral part of the institution’s Landscape Heritage Plan. This document exists to “guide campus planning and design for generations to come.” UC-Berkeley’s Landscape Heritage plan “lays out a comprehensive vision for campus buildings and open space,” and “examines the key characteristics of the historic Classical Core and provides guidance for its continued development in a manner that respects and builds upon its unique landscape legacy.”
UC–Berkeley’s plan includes specifications for modular pavements. According to the plan, “the use of modular pavers on walks and plazas is consistent with the historical character of the Classical Core. They permit water percolation and are reusable after trenching or repairs if constructed with un-mortared joints. Modular pavers set over a pervious material improves stormwater management, reduces long-term maintenance costs and repair time, and supports the sustainability goals of the campus.”
Other precast elements in UC–Berkeley’s Landscape Heritage Plan specifications include balustrades (“A custom designed element… Construct only of granite or precast concrete.”), bollards (“Resembling a stone bollard in general appearance, a precast concrete may be used adjacent to neoclassical buildings or in plazas. Precast concrete bollards are appropriate for use in the neoclassical and urban landscape types.”), and benches (“Benches constructed of precast concrete are specialized elements suited for entries and plazas around neoclassical buildings. Several varieties of precast concrete benches now exist in the Classical Core. The precast concrete bench is appropriate as the standard bench in hardscape areas throughout the neoclassical landscape type.”).
Concrete — A Lasting Choice
As evidenced from the Romans, concrete stands the test of time. It also stands the test of hardwearing college students. “You can’t carve your name in it or burn it or turn it over,” said Ebbert. He added that precast products could include a sacrificial coating so solvents are not required to clean any graffiti.
Precast concrete has the advantage of being made in a controlled environment, meaning the product can’t be affected by outside elements like bad weather. Companies producing precast can also work 24 hours a day, so they can turn a product around quicker if need be. Precast can also be color-matched perfectly.
Precast pavers can handle changes in temperature better than cast-in-place. “Each brick acts as its own unit and locks into the whole,” said O’Neill. “That means that the product can move with the ground, and not crack and cause tripping hazards.” Precast can be more expensive than cast-in-place, but the more intricate the project, the more competitive it is. “And precast doesn’t need the maintenance that cast-in-place does,” continued O’Neill. “If you need to get to utilities under a walkway, you just lift individual bricks and put them back when you’re done.”
Along with benches, signs, planters, walkways, parking lots, and walls, precast concrete can be formed into beautiful art installations. At the University of California San Diego, US Concrete helped artist Kiki Smith with a sculpture. “We precast a tree that was removed from the middle of campus, and Smith put a sculpture on top,” said Ebbert. “It’s really amazing.”
Think beyond the four walls of a new building when considering precast concrete. Today’s precast manufacturers can offer an endless variety of shapes, textures, styles, colors, and forms — from wood-look fencing to polished granite-style planters to brick-like pavers and so much more — in a sustainable, economical product that will enhance your campus landscape.