Soil Stabilization in Site Development

by Diana Barnum
Making a profit through asphalt recycling while at the same time extending pavement life and stabilizing soil beds is the bread-and-butter of Kelchner Excavating’s growing business.

The Dayton, Ohio-based company utilizes a proven method of extending pavement life while reducing maintenance costs through soil stabilization.
In a nutshell, stabilization is the mixing of lime or cement with subgrade soils so that a chemical reaction results in a more durable, stable subgrade.
“We also do full-depth, in-place recycling of asphalt. The beauty of it is that we use mobile equipment,” said Todd Kelchner, owner of Kelchner Excavating.
His company specializes in excavation, utilities, stabilization and landfill construction. With approximately 90-100 employees, the goal is $17.5 million in annual sales, a figure they are right on target to hit. And asphalt recycling and stabilization is generally targeted at 8% to 10% of the company sales, notes Kelchner.
When asphalt surfacing shows that “alligatoring” effect with cracks in the surface or potholes, a couple of options are available. A new layer of asphalt can be applied inexpensively. However, just as repainting over chipped paint would eventually reshow the chips and at best is only a temporary fix, the same holds true for asphalt recovering. A different alternative is to take out the asphalt and gravel base and replace it with all new material, correcting the main problem: a weak subgrade.
Kelchner’s steps in soil stabilization:
1. Go in and grind up to about 18-inches deep. Pulverize asphalt and mix gravel and dirt base.
2. Introduce precise measurements of lime dust or cement material over the top, add water and mix. The result is firm subgrade, like concrete, in 24 hours or less.
3. After drying, add new surface of traditional asphalt, about 2-inches thick.
Equipment for the soil stabilization process includes a standard paver and a CMI RS650 grinder. Kelchner also uses a homemade truck for lime dust, created out of an articulated haul truck. In place of the removed truck bed, he placed a tank outfitted with an agricultural application for computerized controls to effectively handle dust emissions and to measure lime by dialing in precise rate per square yard.
In a white paper called, “Benefits of Soil Stabilization in Site Preparation for Parking Lots, Roadways and Building Pads”, Kelchner Excavating points out the primary economic and structural benefits as:
• Reduction of surface maintenance costs by at least 50%.
• Extension of pavement life by as much as twice that of non-stabilized surfaces or 100%.
• Improvement in materials’ resistance to moisture, thawing and freezing conditions. And resistance to expansion, swelling, cracking and buckling like unstabilized clay.
• Reduction in pavement thickness requirements - resulting in lower costs.
• Improvement of construction site conditions and scheduling with decreased downtime even in bad weather.
Savings? Let’s look at some projects and see.
On a project in Dayton, Ohio, Kelchner Excavating contracted to develop a 225,000-square-foot shopping center. They used the CMI RS 650 to grind 70,000 square yards of asphalt parking lot and crushed concrete for base under the Wal-Mart. Then they pulverized the asphalt and mixed it in with gravel materials from underneath to create gravel backfill and a gravel road-base for their parking lot. The grinder operated at a rate of about 10,000 square yards per 10-hour shift.
“We probably saved them $100,000,” said Kelchner.
At a site in Beavercreek, Ohio, Oberer Development was working on 6,000 square yards at the 30-lot Kables Mill Subdivision in Green County. When the site contractor began street work, he could not pass a proof-roll inspection, even after trying for a couple of weeks. Kelchner was called. In less than three days, they had the project stabilized and passing the proof inspection even with heavy rains ongoing.
At another site, a distribution center in Cleveland, Ohio, Kelchner worked with a general contractor on a 100,000-square-foot warehouse and parking lot. These results were reported:
“... a longer lasting parking lot, that will have less than half the normal maintenance cost over time, and the owner paid nothing extra for the stabilization. By properly assessing the increased strength gain by stabilizing the sub-grade, the originally designed base and asphalt thickness was reduced, saving enough money to pay for the total cost of the stabilization.”
On another project, a retail Store in Saginaw, Michigan, Kelchner was a sub-contractor for a 150,000-square-foot building. The soils were wet and soft, slowing down work. An estimated entire summer — or three months — would have been needed to conventionally dry out the area using disking and aerating. However, Kelchner’s soil stabilization with lime speeded up the process in one week.
For more information about soil stabilization, contact Kelchner Excavating at 6834 Loop Road, Centerville, OH 45459. Call toll free: (800) 229-1334, or fax inquiries to: (937) 434-3807.