New concrete slab system expands floor further with joints that are fewer and farther between
Pinpointing the negatives of conventionally designed concrete floor slabs is not difficult: Curling, cracking and too many joints can cause numerous challenges.
Curling occurs at the edges of concrete slabs when relative humidity between the top and bottom of the slab differs. Usually the top dehydrates faster than the bottom. As a result, the slabs lift up from the subbase at the edges.
"At that point, you're going to have 30-40 percent of the floor slab no longer in contact with the subbase," said Greg Scurto, founder of DUCTILCRETE® engineered systems. "Now you're relying on the tensile strength of the concrete to bear your loads."
This is not good. Especially when concrete floors in places like large warehouses endure continual wear and tear from heavy forklift traffic. The forklift drivers experience bumpier and bumpier rides. Worse yet, the rides are rougher on the floors, which succumb to chipping, cracking and other deterioration that requires maintenance over time.
Not so with the unique, patented technology called DUCTILCRETE® engineered systems.
Using a precise method of floor design and installation, fine-tuned over 16 years, DUCTILCRETE® engineered systems have revolutionized the concrete flooring game. The recipe includes specially formulated admixtures, fibers and a careful installation process—a patented layered system that only licensed contractors can implement. The result is more continuous, smooth concrete floors with far less joints and thus far less opportunity for damage.
"Conventionally designed slabs are really designed to fail," Scurto said. "Saw cuts every 12 to 15 feet are essentially pre-engineered cracks. The DUCTILCRETE® system eliminates 75% of those control joints."
The secret is in the "creep," or inelastic deformations that occur over time, as the concrete bears loads. Creep is a bad thing in concrete columns. In high rises for example, too much creep can cause the columns to compress. In a slab on-grade, however, creep is a good thing. Concrete with higher creep is more pliable and more ductile by nature.
"Without creep, concrete floors will eventually curl like a dried leaf," Scurto said.
The DUCTILCRETE® system achieves creep by lowering the differential shrinkage between the top and bottom of the floor slab. Not only does this reduce curling, it drastically reduces the number of joints across the entire floor. To date, 2,000+ miles of contraction joints have been eliminated with the use of the DUCTILCRETRE® system.
Every DUCTILCRETE® project is specifically designed to perform according to the client's load requirements, their traffic requirements and their soil issues. It's truly an engineered system for concrete slabs and not just a product we sell."
By designing to the client's specification and working with the structural engineer of record, as well as expanding into more advanced admixture technology, GCP Applied Technologies and its DUCTILCRETE® engineered systems line is stretching the limits of what the concrete floor can do.
The ultimate goal for everyone involved is a continuous, jointless concrete slab at costs comparable to a conventional concrete slab. If history is any indicator, the road ahead looks smooth.