When the Michigan Department of Transportation decided a road-widening project along a 6.75-mile stretch of Lake Michigan Drive (or M45) through the town of Allendale would be necessary, that meant leveling several hills and valleys along the two-lane rural road to create a divided four-lane boulevard.

But there was a challenge, and one that more and more engineers are facing on highway construction projects as the supply of suitable acreage for transportation infrastructure diminishes.

An expansion of the busy rural artery could not happen until the load on another nearby lifeline — a buried water main that supplies up to 45 million gallons per day of the vital resource to the greater Grand Rapids area — was also lessened. In some places, the road-widening project would cover the existing road level with up to 20 feet of fill.

A traditional sand fill would exert a 2,000-pound-per-square-foot load on the waterline, which was built in 1939, and that would present too much of a rupture risk to the 46” diameter, wire wound reinforced concrete waterline.
Motorists who use the 25 miles of road to commute between Grand Rapids and the shore of Lake Michigan and the metropolitan area’s water customers both relied on a solution. So, road engineers turned to a less traditional, more innovative fill for the job.

The engineering firm of Wilcox and Associates of Caledonia, Michigan, specified Geofoam, the generic name for large blocks of expanded polystyrene, manufactured by Falcon Foam, for the project. Falcon Foam is a division of Atlas Roofing Corporation that specializes in the development and manufacture of quality HCFC-Free Expanded Polystyrene insulation products.

Geofoam is an environmentally responsible fill option that does not contaminate ground water or soil, according to Scott Miller, Engineering Manager for Falcon Foam in Byron Center, Michigan.

This was not the first time Geofoam has been used in Michigan, Miller said. The transportation department has found many applications for Geofoam on its road building projects.

“They have put a lot of foam in the ground for a lot of reasons,” Miller said. The transportation department also specifies Geofoam in road projects involving construction over underlying soft soils unable to carry designed loads and alongside bridge and foundation walls as a soil substitute to reduce horizontal loading.

In some cases, the foam can reduce the amount of steel reinforcement and concrete needed to build bridges because of a reduction in the lateral load, Miller noted.
In the case of the M45 project, the foam greatly reduced the weight over the waterline. As an example, a 20-foot by 1-square-foot column of Geofoam weighs just 31 pounds, Miller explained. Over the entire project, the foam blocks weighed a combined 533,000 pounds and represented just 1.5 percent of the nearly 36 million pounds of sand fill that the Geofoam blocks replaced. That’s just over a 1 percent strain level.

To gain perspective on how much foam was placed under Lake Michigan Drive, Miller offered a useful sports analogy: “The 4,100 blocks of Geofoam used in the project would cover a football field stacked over 87 feet tall.”

The foam blocks can carry the enormous weight of a four-lane boulevard and the traffic it carries because over the surface of the blocks they can withstand a tremendous amount of pressure, Miller explained. The blocks for the M45 project were at 1.54 pcf density EPS. But Falcon Foam can adjust the density to the specifications of most projects. Each block is molded at Falcon’s Byron Center manufacturing plant and then the blocks are cut to size before they are delivered to the job site.

Field cutting can be easily achieved at the job site, especially in cases of road building around existing manholes.

The individual block on the M45 project weighed 130 pounds and was 32” x 48” x 96” in size, making installation of the blocks easily accomplished by two workers.

Before the road could be surfaced, the sides and tops of the blocks were wrapped in a PVC liner to prevent degradation of the foam in the event of a petroleum spill on the highway. Dirt was moved to road level to secure the blocks from any side-to-side movement. On top of the blocks, a minimum 3-foot layer of sand and gravel kept the foam below the frost line and at a constant 50 to 55 degrees Fahrenheit to further prevent degradation of the Geofoam. The road was surfaced with bituminous asphalt.

Bruce Morren was project manager with the project’s general contractor, Nagel Construction Inc. of Grand Rapids, Michigan. He saw the project to completion in November 2002. The project had begun in April 2001.

The foam blocks left the factory and arrived by flatbed truck—each carried 36 blocks—and were unloaded at the road work site with a front-end loader.

Morren said he enjoyed working with Falcon Foam, which delivered enough Geofoam to cover a nearby 10,000 square yard area with the product.

“They made it faster than anybody else could in the area,” Morren said.

On site, the product had to be covered to prevent UV light degradation to the Geofoam. The tarp was weighted to prevent it and the foam from blowing away in the wind and possibly damaging the blocks.

The advantage to using Geofoam over sand as fill for the project was safety, according to Morren. “The labor cost is probably about the same but the safety factor is key,” Morren said.

During July and August as the Geofoam was being laid, about 40 to 45 million gallons of water per day flowed through the line serving the City of Grand Rapids, Morren noted. If a heavier fill was used or the equipment moving the dirt for the foam fill punctured the line, it would have taken two to three hours to shut off the water flow. A ruptured line on this job would have been fatal to those people installing the fill.

“When you put the foam over the line you know you are not going to disturb it,” Morren said.

Miller noted safety is one of several advantages to foam fill. Geofoam is the more cost effective choice of fill when sand fill requires long-distance transportation.

“That’s one of the most tremendous savings,” Miller said.

Other benefits include a reduction of labor costs and project schedules, according to Federal Highway Administration officials. Geofoam also can be constructed easily in limited right-of-way areas and in adverse weather conditions, officials said.

Installation of the Geofoam was a snap, according to Morren. Each foam block was fastened into place with 4” by 4” galvanized steel connector plates. The blocks were laid perpendicular to the previous layer with the vertical joints offset to the greatest extent practical. Morren compared it to building a brick wall.

The multi-layered foam blocks were placed in trenches that had been cleared of vegetation and any large sharp-edged soil particles prior to placing a geotextile and/or sand-bedding layer. The plastic liner was installed in 20-foot lengths and overlapped by 18 inches. The foam was then covered by 5 feet of sand and gravel. The road was surfaced with bituminous asphalt.

This was the second road project incorporating Geofoam that was successfully completed by Nagel Construction. The firm has been in the road, water and sewer excavation business since 1958.

The first Geofoam application by Falcon Foam was in 1996 for a bridge approach in northern Michigan. Since then, Falcon has provided Geofoam blocks, technical assistance and engineering for road and underground construction projects throughout the United States and Puerto Rico.

The first application of foam in highway construction dates back more than 40 years ago and was installed in Finland. Styrofoam was first use in road building in the United States more than 20 years ago.

According to the U.S. Department of Transportation’s Federal Highway Administration, the foam has been used on higher profile jobs in the United States by comparison to the Lake Michigan Drive project. The larger ones include the Interstate 15 project in Utah and the Big Dig in Massachusetts.

Both projects turned to EPS Geofoam to complete large embankment sections under extremely tight construction schedules that would not have allowed enough time for conventional embankment construction, according to the federal agency.

Geofoam embankments can be covered to look like normal sloped embankments or finished to look like a wall. Geofoam can be used to repair landslides and to lighten loads over culverts or other structures.

“We’re up to about a dozen states that have used Geofoam with success,” said Silas Nichols, a geotechnical engineer for the Federal Highway Administration. SLDT