“We performed an in-place cement stabilization, mixing the cement with the pulverized asphalt and existing base materials at a 10-in. depth,” says Faust.
With any FDR job, soil conditions, moisture control and achieving good compaction are key components. Soil conditions in this particular region were sandy clay with some river rock.
“Based on the lab soil reports, we infused the pulverized materials with 56 lbs. of Portland cement per square yard of road,” says Anders. “The newly mixed material was graded, compacted and kept moist until the contractor was able to prime and sand the newly reclaimed section.”
“On this particular project, challenges included getting gradation with the constant changes in asphalt thickness and surface conditions present,” Faust comments. “Another challenge was paying close attention to the moisture content with the varying soils over the project.”
For the final overlay on the project, 66,569 sq. yds. of type “J” bituminous surface treatment was laid, with 1 1/2 in. of asphalt topping on most of the road. The section in front of the rock quarry received 9,570 sq. yds. of a type “L” treatment and 2-in. binder course. Charles E. Watts Inc. performed the surface treatment work, and APAC Midsouth handled the paving.
The outcome and cost savings
The potential benefits of using the FDR process include less maintenance, safer travel conditions and long-term stability of the base material, says Anders.
“On the Wire Road project, the outcome is yet to be seen,” Anders comments, noting the total project cost was $1,054,121.34. “Based on the best available information, we are anticipating a 15- to 20-year life span of the concrete reclaimed base. Our records show we have been averaging spending $75,000 per year on this portion of Wire Road, not counting resurfacing.”
At that rate, the savings mount up quickly. “Hopefully, it will take 15 to 20 years before we can calculate the total savings,” Anders states. ET