When cantaloupe-sized chunks of concrete start falling down from bridge decks to the roadway below, it’s time to take action. The Kentucky Transportation Cabinet (KYTC) decided to fix the problems on the heavily trafficked I-64 highway through downtown Louisville and do it on an accelerated schedule.
“The rehabilitation we envisioned usually takes an entire construction season from May to November,” said Matt Bullock, chief district engineer. “Instead we decided to try to do it in one month, plus three weekends.”
The KYTC and contractors had done accelerated work on I-64 and I-65 in Louisville, but never on a project of this magnitude. The project covered 21 lane mi. and required the saw cutting of 132 joints. “With those joints removed, an asphalt surface would give motorists a smooth ride,” said Bullock. “We also didn’t want the motorists to put up with construction on that vital road for the whole summer. That wears on them.”
The project was completed a week ahead of the accelerated schedule and used an epoxy-like, highly polymerized asphalt on 13 bridge decks. Gohmann Asphalt & Construction of Clarksville, Ind., had used the mix before on another project and was selected to do this project, which was known as Restore 64.
Low Air Voids
One requirement of the mix for Restore 64 was highly impervious, an important factor for the numerous bridge decks that were paved.
“The mix had less than 1 percent air voids. That keeps the water out of the pavement and prevents it from corroding the bridge decks beneath,” said Tom Partipilo, vice president of Construction Materials Laboratory (CML). CML is a sister company of Gohmannn and handles many of the QC/QA tests for the firm. “This asphalt material is also very tough and rut resistant.”
The project required 78,000 tons of asphalt which included 22,000 tons of the epoxy-like polymer mix.
Cost was a factor as well for the mix.
“Although this was an expensive asphalt mix, it was still about one-half the cost of a latex overlay. And the latex overlay could not have been done in the accelerated time frame of this project,” said Partipilo.
The proprietary mixture required high temperatures for the polymers to achieve proper viscosity. It also required special handling for the paving process. The paving crew used smaller rollers and a different rolling pattern than usual to prevent surface cracking from occurring.
“Restore 64 has been a huge success,” said Bullock.
In addition to the road work, the project included constructing new barrier walls, repairing structural steel components, and replacing overhead signs.
“We are extremely happy with the timely progress construction crews made on this enormous project,” Bullock said.
This article was reprinted from HMAT magazine, November/December 2007, Volume 12, Number 6.