"When you have to undercut a road by 16 inches to place new rock, you are going to have to get utility clearances and relocates," says Indrunas. "All this takes time, and we knew this project would take up to six months to perform. We were shocked when we rebid this same road as a reclamation project the following spring and the successful low bidder was awarded the work at just over $270,000."
While still skeptical of the process, Indrunas gleamed at the fact that his city was looking at a potential cost saving of over $1.2 million.
"In addition to the monetary savings, having a roadway open to traffic after seven or eight working days with reclamation versus six months with conventional construction is priceless," says Indrunas. "Rather than waiting for utilities to be relocated and adjusted as in conventional reconstruction, the Blount Construction crew simply pulverized and mixed the existing asphalt and base, trucked away surplus material to make room for curb reveal and injected lime and foamed asphalt into the ground up road mixture. We got the strength of a brand new road for a fifth of the cost and substantially less time than conventional reconstruction."
Though the project went well, there was still plenty to be learned in the developmental stages of this process. "There is a definite learning curve out here, but we work closely with the low bidders of these projects to achieve the desired results," says Indrunas. "We learned very quickly that there is a trade-off between following the old in-place curb with the new road and rideability. We soon found out that it is best to ignore the old curb profile and focus on the finished ride. With 15,000 cars a day on these roads, you only get one chance to get in and do the work, so we learned that it is imperative to get it right the first time."
With two successful foamed asphalt base stabilization projects, Roswell staff went to work on the budget for 2003. It was now a question of where to use full depth reclamation with foamed asphalt rather than should we use it. The cost savings alone was reason enough to plan on using it in following years. It looked as if the days of adding more and more layers of asphalt resurfacing, then raising the curbs were soon coming to an end in Roswell.
In 2003, Hardscrabble Road Reconstruction Project was let and the bids came in to do this reclamation project with a combination of 2.4 miles of foamed asphalt base stabilization and a half mile of milling and resurfacing. Mix designs were prepared and Blount Construction went to work as a sub to APAC Paving to prepare a 5-inch stabilized base under their 2 inches of asphalt overlay. With the road closed to local traffic only, reclamation crews were able to expedite the work in record time.
"Here is a road with 16,000 cars a day being completed in 10 days versus being done in six to seven months with conventional reconstruction," emphasizes Indrunas. "Even if we chose to do deep patching instead of conventional reconstruction to save time, unless you are going to go down 10 inches with your patches, the patch method cannot address the sub base failure problems the way full depth reclamation does. I have the reclamation crews go down as deep as 18 inches on occasion to inject extra quick lime to stabilize sub base problems prior to stabilizing the entire road."
Knowing that the sub base failures are properly addressed and that the foamed asphalt base has a long life cycle when properly performed gives Indrunas confidence when it comes time to tell his elected officials that their engineering staff can meet their 20-year lifecycle expectation. As Roswell experiences unprecedented growth, additional subdivisions have been added to the original road design.
"We can adjust and correct the resultant drainage deficiencies," says Indrunas. "Now with proper drainage, cross slope, width and uniformity, we are giving our taxpayers roads that are new for a third or more of the cost of conventional reconstruction. The fact that we can do this recycling reconstruction in record time under traffic is invaluable. On some occasions where it is feasible, road closures can expedite the construction time even further. Backing up 20,000 cars a day is not an option anymore in this just-in-time age."