When traveling along the Illinois Tollway in the Chicago area, you will notice the 75,000 acres of the right-of-way is covered with grass, trees, flowers, and shrubs. The landscaping is not only pleasing to look at but serves to prevent erosion along the Illinois State Toll Highway, stretching 274 miles of roadways.

The Authority chose American Excelsior’s Curlex II Double-Sided Erosion Control Blanket for their widening project. Curlex’s product was the perfect choice for a strong ground cover that would protect the soil and germinate seeds on the Authority’s landscape program for this project.

Once construction of the stretch of the tollway was completed, steps were taken for the landscaping project. The slope was established, prepared, seeded, and then the blankets were installed. Where it was possible, the Authority tried to reduce cuts and very steep grades for more successful erosion control and safer maintenance procedures.

The Curlex blanket has performed very well for the Tollway Authority. It offers a nice environment for seeds to grow by maintaining moisture in the soil but also helps with weed control and prevents any excess soil and seed loss due to wind and water erosion. According to Bob Klatt, Landscaping Coordinator for the Tollway Authority, it allows seeds to settle and germinate. Once this has occurred, the blankets degrade, going back into the environment and the seeds can start developing.

The blankets combined with a mat of curled Great Lakes Aspen wood excelsior with a tough photodegradable plastic mesh will remain in place even on rough terrain. Curlex fibers expand when they are wet and when moisture is released, the fibers contract. This natural motion creates a digging effect that produces a superior soil adhesion.

The Illinois Tollway Authority installed approximately three million square feet of blankets on their project at a cost that’s less than 4% of the total landscape and restoration budget. According to Bob Klatt, it is a very cost-effective way for total erosion control.

The Illinois Tollway Authority has used other erosion control blankets in the past, even though they have a long history with American Excelsior. At one time, they used another Manufacturer’s straw blanket that seemed okay. The downside, the blankets curled because they were lighter than Curlex’s blankets. They also discovered the straw blankets would blow and rip from the wind caused by trucks passing along the roadway. Bob Klatt said that even though they want their highways to look attractive, the landscaping, green grass, and flowers, are only eye-appealing benefits. Their leading concern is the landscaping functioning properly. Trees block roadway noises and pollution, and their grassy areas will prevent erosion.

Going Green

Going green has become a popular phrase including on construction sites. Constructing a green building can decrease costs and provide good things for the environment. As an example:

There is a building in a car dealership located in Clermont, Florida. The building is the first LEED Platinum Certified dealership in the state. Installing a green roof was initially for getting their LEED Platinum Certification. If you don’t know, what a green roof is, it’s a roof on a building that is covered in vegetation. The vegetation is planted into the growing medium over the waterproofing membrane. A green roof offers many great benefits:

- Reduces heat island effects by absorbing solar radiation.

- Serves as storage for rainfall which is then released by plant transpiration and evaporation.

- Reduces the amount of storage water discharge into MS4s and the danger of flooding.

- Filters out airborne particles by trapping them on the greenery then washes them into the growing medium when it rains.

- Absorbs pollutants such as carbon dioxide and then releases oxygen into the environment.

- Offers additional insulation to lower heating and cooling costs.

- Offers great habitats for birds

- Provides aesthetically pleasing appearances for the building’s occupants

- It might qualify for tax benefits from cities.

This building was designed for keeping the environment at the top of the list and uses less energy. The idea of the project was to pass the savings onto customers.

Installing a green roof will meet the rules for stormwater that are in place for Florida and the EPA Turbidity Guidelines.

The Project Team

Tecta America is a contractor located in central Florida. They were contracted for the installation of the green roof for the dealership. The Director of the Water Research Center and Stormwater Management Academy at the University of Central Florida helped with the green roof installation as a consultant and designer.

John Slupecki is the Territory Manager for the American Excelsior Company. He supplied Curlex II QuickGRASS for the project to protect the growth media.

Preparing And Planning Before Starting The Project

Tecta America’s green roof system is multi-layered with several layers of the lightweight growing medium which reduces the building’s structural costs. The soil medium was devised through the University of Central Florida and consists of two material types:

• A lower layer for pollution control
• An upper layer for vegetation growth

Also, flowers were selected for the green roof application.

The Project

The irrigation system was placed over the soil media. Curlex II QuickGRASS was installed to protect the growth media until the native wildflowers are put into the layered system than allowing them to become established.

According to Marty Wanielista, bringing green roofs to life has been helped by American Excelsior and their blankets.

The professional crew did not run into any problems with the 4,800 ft building’s green room installation. It required a crew of four people and was finished in less than 8 hours. Note, a two-person crew can install approximately 800 ft in an hour.

In Summary

The use of Curlex II QuickGRASS to protect the soil until the vegetation is established was a great success. The features added to the building’s LEED Platinum Certified Rating and continue to reduce operating costs for the owner while increasing the benefits to the entire community.