Sometimes the key to success is putting in long hours. And sometimes, in order to be one of the best, you have to work around the clock. This year’s finalists for the Sheldon G. Hayes Award found the latter to be the key to their successes.
Both Scotty’s Contracting and Stone LLC of Bowling Green, Ky., and APAC-Missouri Inc. of Springfield, Mo., were faced with challenging road conditions to repair and tight time constraints to work with. In order to get the job done and get it done right, they had crews on the job 24 hours a day. In the end, both contractors were able to meet their deadlines and were honored as finalists for the Hayes Award for excellence in construction of an asphalt pavement.
Rough roads to smooth sailing
Scotty’s Contracting and Stone was recognized as finalist for the second year in a row for their overlay work on 17.6 miles of the Western Kentucky Parkway near Beaver Dam, Ky. The existing concrete pavement, previously overlaid nearly 20 years ago, was in extremely poor condition and made the job particularly challenging.
“We built off of the old layer of rough asphalt and we put a leveling course of about an inch back in to fill and level up the road, and then we put [down] 11?2 in. of asphalt Superpave surface,” Michael Law, operations manager, told Roads & Bridges magazine. “So we’re really only talking about 21?2 in. to take a very poor riding road and make it a lot smoother and a lot better.”
The $10.2 million job presented Scotty’s with several challenges, particularly the base failures during the prep work. “There were a lot of base failures where the old road had fallen through or the sub grade had failed, so we had to dig those out,” said Law.
After those spots where dug out and filled back in with a base asphalt, crews were able to mill about 21?2 in. and then lay the leveling course and the surface. According to Law, it was a challenge to take such a rough old road and use their equipment and electronics to create smooth pavement again.
With the base failures and leveling and surface courses, a total of 116,270 tons of asphalt were used on the job. When the time came for the fresh mix, Scotty’s used a Barber Greene 6,500-lb batch plant that produced 200 to 250 tons of asphalt per hour. The plant itself was located in Hartford, Ky., 15 miles from the jobsite.
The Barber Greene batch plant is one of Scotty’s older plants and doesn’t produce as much materials as their other plants. In order to compensate for this, and to ensure that the job was completed by the deadline issued by the state of Kentucky, an additional paving crew was brought in for about a month during the night and ran the plant 24 hours a day.
“Scotty’s Contracting has two paving divisions, and for this job both paving divisions came together and used one paving crew from each to attack the work,” said Law. “That’s something we don’t do too often, but in this case it worked very well for us.”
Work on the 17.6 miles of roadway began on July 1, 2003, and with the two crews working around the clock the project was finished by Nov. 1, 2003.
According to Law, there was a tremendous amount of testing done at the plant itself: The mix was sampled at least once every 1,000 tons and over 100 quality control samples taken at the plant.
Tests for air voids also were done at the plant, and a Pine gyratory compactor was used to create the lab samples. The surface mix itself had an average air void of 3.7% and was very consistent, with a range of 3.3% to 4.1% and a standard deviation of 0.38.
“Looking at the testing that was done, in my opinion it was probably one of the best or most consistent jobs or mixes we have ever produced,” said Law. “We hit our target air voids, and all of our control sieves we hit and kept very consistent.”
There was pulverized asphalt and a PG 76-22 binder in the surface mix itself, and the temperature of the asphalt leaving the plant was between 320° and 330°F.
The job consisted of a leveling course lift with a 11?2-in. course on top of that, which was a 1?2-in. maximum size Superpave surface with skid resistance used for safety and wear purposes over time. The surface course itself was the 1?2-in. maximum size and used non-skid sand hauled in from Springfield, Tenn., as well as some natural and locally manufactured sand. The liquid used for the mix was PG 76-22, and the temperature of the asphalt at lay down was approximately 310°F.
Forming the paving train were two pavers—a Blaw Knox PF5510 tracked paver and a Blaw Knox PF172B rubber-tire paver. A Roadtec SB2500 shuttle buggy was used as a transfer device. Bringing up the rear were two different kinds of vibratory rollers: a Cat 634C and an Ingersoll Rand DD90HF.
Testing performed at the jobsite itself consisted of density and smoothness testing. For density, a quality control person used a Troxler nuclear gauge to check behind each of the rollers. The pavement was then cored—four cores per 1,000 tons—and was turned over to the state of Kentucky for incentive/disincentive pay on the density portion. “In Kentucky, 45% of the pay is based on density,” said Law. “It’s a very large priority for us.”
The average percent of solid density was 93.8%, and in the state of Kentucky, they award a bonus for 94% to 96% maximum. Scotty’s Contracting met or exceeded the minimum quality level required and received a bonus for about half of the core density readings that were taken.
In terms of smoothness testing, the average ride quality of the job was 40.76 IRI (international roughness index). The Kentucky Transportation Cabinet performs their own smoothness testing, and every portion of the 17.6-mile road met the ride-quality standards set by the state. Scotty’s Contracting received a bonus award of $200,525 for the job.
With crews working around the clock for most of the job, the project was completed in four months time and several bonuses were achieved, leading Scotty’s Contracting to the second Hayes Finalist Award in two years. “We take a lot of pride in the work that we do and to be recognized for that is a great thing,” commented Law.
Also recognized as a finalist for the 2005 Hayes Award was APAC-Missouri of Springfield, Mo., for transforming the roughest and most deteriorated 6.7-mile portion of I-44 in Jasper County into an exceptionally smooth roadway.
The condition of the existing 8-in. concrete pavement was extremely poor and APAC was faced with several challenges in terms of pavement repair. The roadway was built in 1964 and had not had any major construction done before this job.
“The first thing we did was pavement repair where they cut out the joints in the concrete and poured concrete patches back,” said Project Engineer Doug Fronick. “[The road] was deteriorating faster than we could get the patches in there.”
APAC began the work in mid-March, and had anticipated to finish pavement repairs and begin paving by the end of April. However, with the poor condition of the existing road, APAC was still pavement patching in the beginning of July, which posed some scheduling problems.
Once the pavement patching was completed, APAC began to run two crews around the clock in order to get the job done faster. “We started Sunday at midnight and we did not stop, unless we had weather or equipment failures, until Friday at midnight,” said Fronick. “So you’d have one crew step off the paver and another step right on and keep on going right on down the road.”
Nearly 100,000 tons of asphalt were used for the 53?4-in. overlay project, which ended up costing $6 million with all of the overrun on the patches. A double-barrel Astec asphalt plant was used near Joplin, Mo., about 15 miles from the job site. Crews were able to lay 200 to 250 tons of asphalt an hour.
The pavement train consisted of a Roadtec SB2500 shuttle buggy, a Roadtec 185 paver, two Ingersoll Rand DD130 breakdown rollers, a Caterpillar 360 pneumatic roller and an Ingersoll Rand DD110 finish roller.
The project itself consisted of three lifts: two 2-in. lifts and a 13?4-in. lift. A PG 70-22 binder oil was used for all of the lifts, and Superpave 190 was used on the bottom two lifts, while Superpave 125 was used for the top lift.
Smoothness testing was performed at the jobsite, and the finished roadway had an impressive profile index of 11.83 in./mile, earning APAC-Missouri a 105% bonus for road smoothness.
Despite schedule setbacks at the beginning of the project, a grueling work schedule of 12 hours on and 12 hours off allowed APAC to finish the project on time. According to Fronick, winning this award said a lot about hard workmanship of the crews who were out there every day putting in the time and effort.