"The Addams Family" came to mind as workers used a nontraditional technology to pour the concrete slab for DP Partners' LogistiCourt at Silver Lake project in Stead
"The concrete comes out (of the chute) looking like Cousin It," says Patrick Rucker, development manager for the Reno-based company. "It is all shaggy."
DP Partners used macro polymeric fibers small plastic fibers between 1.5 and 2.25 inches in length in the 545,550-square-foot warehouse on Moya Boulevard. The technology has been available for about eight years, Rucker says, and DP tried it on its newest speculative building because it significantly reduced the number of saw-cut expansion joints throughout the building's floor space.
The use of the fibers reduced expansion joints in the building's floor by 75 percent from one every 12.5 feet to one every 50 feet. In addition, steel rebar was installed only at the expansion joints. Even so, the cost for macro-fiber concrete is about 8 to 10 percent higher than a regular mud-and-steel slab, Rucker says.
"What really made it worthwhile, why we would spend the extra dollars, is the reduced amount of maintenance our tenants would have," he says. "We felt it would be a great marketing tool our floors would be a lot cheaper to maintain and more durable."
Expansion joints limit widespread cracking from developing throughout a concrete slab. But they typically are the weakest point in a slab and absorb the most wear from forklift traffic. As forklifts travel across a slab, one edge of an expansion joint dips slightly and exposes the other. These joints break down over time and must be repaired an expense usually placed on the tenant.
While little-noticed, floors are critical to the operation of a warehouse.
"The slabs are our biggest investment," Rucker says. "The floor supports all the activity. All the product gets stored on it, all the racking is supported by it and all movement of product within the building is supported by the floor."
DP poured two sections totaling 34,000 square feet at its Silver Lake project with the new technology. Rucker says the company also will use macro-fiber technology for slabs in three buildings to be built in Las Vegas totaling 408,000 square feet. Slab maintenance and repair are two one of the biggest issues facing a
warehouse developer once a building is completed.
DP began using the fiber technology at the suggestion of its ready-mix supplier, CB Concrete, and on the advice of structural engineer Jerry Holland of Structural Services Inc. in Richardson, Texas.
Holland says the use of the fibers will eventually become widespread.
"The wheel turns so slowly in the U.S. with respect to significant technology changes like this," he says. "We are such a litigious society that people are reticent to try anything new. But this is a very significant thing that can really revolutionize the industry."
The fibrous material is shipped from a mill in Pennsylvania to the concrete plant, where 7.5 pounds of fibers are added to each yard of concrete. Steel rebar is not necessary because the reinforcing fibers permeate the slab.
"The bottom line for our tenants is that it is going to be less expensive for them to maintain and repair," Rucker says. "And when we get the building back, the floor is going to be in better shape and will hold its value longer and better."
