Material World: Unilock Eco-Optiloc

By October 27, 2015

When it came to the site design, the goals of the Aurora Police Headquarters in Aurora, Illinois were threefold: public safety, sustainability, and creativity. Because the project was attempting to meet LEED Gold certification, the need to obtain LEED points was also a major factor. For the parking lot of the headquarters, landscape architecture firm Schoppe Design Associates chose Unilock Eco-Optiloc permeable pavers as an environmentally friendly solution for drainage. “The major considerations when it came to pavement selection were that it needed to let rainwater pass through it while maintaining the structural integrity of the pavement,” says Schoppe Design Associates principal Mike Schoppe. “It also needed to be light in color in order to reflect as much light as possible.”

The Eco-Optiloc pavers are manufactured with a high-reflective value custom finish and an interlocking L-shape design that can easily handle heavier municipal vehicles, like police vehicles. A cobble-patterned surface allows rainwater to infiltrate and drain via a gently sloped subgrade to a bioswale and sedimentation basin at the south end of the property.

“Permeable paving is an efficient solution for stormwater runoff because it can reduce flooding, increase water infiltration, recharge groundwater, and improve water quality,” says MikeAnderson of Unilock. Not only is the use of permeable pavers a recommended Best Management Practice under the US Environmental Protection Agency’s National Pollutant Discharge Elimination System program requirements, but it is also a recommended construction practice under Low Impact Development and Leadership in Energy and Environment Design guidelines.

Able to withstand heavy loads, the specially designed L-shaped concrete pavers feature large spacer bars that create gaps or enlarged joints between the units, allowing for surface infiltration. Aggregate material within the joint filters rainwater flowing into the base. According to Anderson, the shape of the pavers prevents shifting or twisting due to vehicles breaking and turning, which increases the structural performance and reduces annual maintenance costs. “L-shaped pavers can also be mechanically installed, significantly reducing the initial installation cost when compared to manual installation,” Anderson says.

Utilizing tri-axis engineering first introduced to North America by Unilock, the pavers satisfy requirements for structural integrity, safety, cost, environmental impact, maintenance, and field-proven performance, and they also provide skid resistance and durability. The pavers are also a flexible system, so their surface area can move slightly without jeopardizing the structural integrity.

“At the grand opening when buckets of water were dumped onto the Eco-Optiloc pavement and it immediately disappeared to the applause of the crowd, we knew that we had made the right pavement choice,” Schoppe says.