Slurry Pavers: A Soil Stabilization Success Story

Things weren't looking so good for the Road Reclamation division of Slurry Pavers. Just three years after they started doing road reclamation, Slurry was considering selling its equipment and getting out of the business. The company planned on dumping the division that was losing some $300,000 a year and focusing on its established, profitable divisions.

As a last-ditch attempt to salvage what they thought could be a profitable line of work, Slurry Pavers moved Larry Roberts into the manager's position of the Reclamation division in August, 2001. Within two years the division turned a profit. In October 2006 Slurry started work on its biggest job to date, the new 4th Runway construction project at Washington Dulles International Airport in Washington, D.C. The expanded Road Reclamation and Soil Stabilization division now accounts for 14 percent of Slurry's revenue.

Secrets to Success
The keys to this amazing turn-around? Roberts cites three. First, Slurry had to expand its vision. "We were doing only full-depth reclamation." With FDR a machine passes over a pavement section, pulverizing the existing asphalt and underlying materials in place. This material is then mixed together in place with cement, lime, or asphalt emulsion to form a stabilized base material for pavement. It's a quick, cost-effective way of rebuilding a pavement section by using the in-place materials, which reduces the impact on our environment and eliminates the damage to existing roads due to the hauling of materials

"But there wasn't enough FDR work to keep our crews busy consistently. With low utilization rates for our equipment, we weren't getting an acceptable return on investment." The solution was to move into soil stabilization, where cement (or lime, in wet conditions) is mixed with soil to form a solid base for roads.

Second, Slurry had to get inventive when they couldn't find the equipment they needed. Roberts designed a spreader that lays down cement for soil stabilization because nothing on the market did a satisfactory job. The cement must be laid down evenly and at a specific rate. On the Dulles project, for example, the rate is 45 pounds per square yard. Tolerance is +6 pounds, -0.

Roberts retrofitted a couple of WWII-vintage military 6x6 trucks with his spreader. The system has worked so well it's now installed on all seven of the company's spreader trucks.

Third, Slurry had to adopt technology that allowed for high-speed, high-capacity, high-precision work. As it has for so many contractors, the technology solution came down to lasers and GPS. Slurry had frustrating results with systems from other manufacturers before finally settling on Topcon products provided by Atlantic Laser Supply. Among the Topcon pieces Slurry is using at Dulles are two PZL-1 lasers, a hiper + rover, and mmGPS units on two motor graders. The general contractor, Lane Construction, has a GPS reference station set up at their job trailer.

Adapting to the technology wasn't hard. Roberts says he had about a two-week learning curve where he worked with the equipment a little bit each day. "The most important thing for me was learning to trust the equipment," he said. John McCormick, their rep from Atlantic Laser, put on a demonstration that helped build the trust factor. "With all the data loaded into one of our graders, John laid a quarter on top of one of our hubs. Using the Topcon millimeter GPS the grader operator swept the quarter off the hub and never disturbed the hub itself."

Big, But Exact
Slurry's task at Dulles is to provide a stable base for the runway and associated taxiways. They're working some 639,000 square yards (132 acres), stabilizing it by mixing cement into the soil. The work is not only high-volume, it's also highly technical. There's little room for error in any task related to the airline industry.