18-mile cut-off

May 11, 2009

Maine, along with many other states, is facing the daunting task of dealing with an aging interstate system.

Built with concrete slabs in the early 1970s, I-295 from Gardiner to Topsham was suffering from accelerated deterioration caused by alkali-silica reactivity (ASR), a chemical reaction between the alkali in the cement and silica in certain aggregates. It results in cracks, disintegration and ultimately structural failure.

Maine, along with many other states, is facing the daunting task of dealing with an aging interstate system.

Built with concrete slabs in the early 1970s, I-295 from Gardiner to Topsham was suffering from accelerated deterioration caused by alkali-silica reactivity (ASR), a chemical reaction between the alkali in the cement and silica in certain aggregates. It results in cracks, disintegration and ultimately structural failure.

The Maine Department of Transportation (MaineDOT) had been evaluating the best way to approach concrete replacement, and in January 2008 charged its design team with recommending a plan. After three days behind closed doors, the design team emerged with a radical recommendation: Close the 18-mile stretch of southbound I-295 from Augusta to Topsham during the peak season of Maine’s $10 billion tourism industry.

The economic, political and community implications of this strategy were not lost on MaineDOT Commissioner David Cole. He assigned Joyce Taylor, assistant director of the Bureau of Project Development, with leading a team that would be responsible for getting buy-in from tourism, community and business leaders; designing safe alternative routes; and putting together the details of the $28 million project for bid, all in time for a June launch. The work was fast and furious during those months but resulted in a project that was hailed by Central Maine’s Kennebec Journal as “an example of how to do things right.”

Given Maine’s short construction season and the potential disruptions to its economy, a start date of June 16 and completion date of Aug. 30 were established. MaineDOT offered a $2 million incentive for early completion and a penalty for delays. The ambitious project included putting down 181,000 tons of asphalt, rebuilding five bridges and installing seven miles of guardrail. MaineDOT ensured this project was designed and implemented to conserve, recycle and reuse whenever it did not significantly reduce the quality of the final product. It also was the first large-scale concrete rubblization project in the state.

The general contract was awarded to Pike Industries Inc. of Westbrook, Maine, with corporate offices in Belmont, N.H.

The project was designed to be built in two phases with very tight work schedules. The first phase was constructed under traffic on the 4-mile southern section from Topsham to Brunswick. Six weeks were allotted with a completion deadline of June 15. The second phase was 18 miles long from Topsham to Gardiner. This section would be closed to traffic at 12:01 on June 16, and the required completion date was Aug. 31.

The scope of work included 245,000 sq yd of concrete milling; 27,500 sq yd of slab removal; 245,000 sq yd of concrete rubblizing; 165,000 sq yd of shoulder pavement removal; 243,000 linear feet of in-slope rehabilitation; 183,000 tons of hot-mix asphalt (HMA); 775 weep drains; five bridge deck rehabs; 43,000 linear feet of new guardrail; 227,000 linear feet of rumble strips; and 507,000 linear feet of striping.

Summer livin’ not easy

Pike Industries’ strategy from the start was to use high-quality subcontractors and take advantage of long summer days in order to complete the project on time.

During the first six-week phase of work, two decks were rehabbed by bridge-work subcontractor Cianbro Corp. of Pittsfield, Maine. Earthwork subcontractor Shaw Brothers of Gorham, Maine, removed concrete, which subcontractor RMI of Tulsa, Okla., had previously rubblized and used to regrade the base. Pike crews laid 25,000 tons of HMA and 500 tons of Rosphalt on bridge decks. Guardrail subcontractor Maine Line Fence of Cumberland, Maine, installed new rail. All work on the 4-mile section was completed, under traffic, in time for the full closure of the north section.

At midnight on June 15, Pike traffic crews closed the 18-mile section, and all southbound traffic was diverted to the detour routes: Rte. 201 (a rural highway that passes through small towns) and the Maine Turnpike (I-95).

Shaw Bros. crews installed the 775 weep drains adjacent to the concrete slabs prior to milling and rubblizing to ensure no water was trapped under the slabs. Cianbro crews made short work of the three bridge decks in the 18-mile closure, including replacement of approach slabs and end caps, as well as deck and expansion-joint rehabilitation.

At dawn on June 16, concrete milling contractor Swank of New Kensington, Pa., began removing 3 in. of concrete from the surface of the slabs. The waste concrete was either deposited directly onto the shoulder or trucked to an onsite recycling area where Pike Industries’ portable crusher processed all the removed concrete into sized shoulder aggregate. All of the waste concrete was used as base material for the shoulders.

Two cold planers removed the shoulder pavement from the 18-mile stretch in less than four days. RMI Worldwide mobilized three Resonant pavement breakers and followed the cold planers. RMI rubblized the remaining 6-7 in. of concrete to MaineDOT specifications of a maximum size of 6 in. This entire process was completed in less than two weeks.

Bottomless quality

On June 23, Pike paving crews began echelon paving of the 3-in. layer of rich base. This mix was a standard 19-mm Superpave design with an additional 1% asphalt added to provide a superior bond to the rubblized concrete surface. The 8-in. HMA pavement consisted of the rich base, another 3 in. of standard 19-mm base, an intermediate 1.5-in. layer of 12.5-mm mix and a final 1.5-in. layer of a 12.5-mm mix. The 12.5-mm mixes for mainline paving contained PG 70-28 liquid asphalt. The standard asphalt used in Maine is PG 64-28. Two 1.5-in. layers of 12.5-mm mix without a binder were placed on the shoulders.

The filling of the “Big Dip” at Brown’s Bog in West Gardiner presented a potential for delays. The approximately ¼-mile-long stretch of highway passes over a “bottomless” bog and has experienced slow but constant settlement since the road was originally built.

Earlier attempts to shore up the section have had limited success. Shaw Bros. crews installed heavy gravel and geotextile fabric in the area and completed the process just a few hours before the base paving crews approached.

Crews from Nicom Coatings of Barre, Vt., applied a rubberized asphalt joint sealer to longitudinal pavement joints. Surface Preparation Tech of Mechanicsburg, Pa., installed rumble strips, and L&D Safety Markings of Barre, Vt., applied striping.

MaineDOT adopted QC/QA specifications and the Superpave Mix Design and Testing system in the mid-1990s. Pike Industries utilized more than 12 quality-control technicians in both the plants and the field to assure maximum performance. Pike produced its own PG 70-28 liquid, which also required two Pike binder technicians. This was a very complex task, with 28 mix designs coming out of four different asphalt plants to as many as five paving crews on any given day. Daily mix production peaked at 6,850 tons, and 6,600 tons were laid on the July 4 holiday.

Specification allowed for up to 5% incentive pay for smoothness, measured by a profilometer and calculated by the IRI system. Pike achieved a 2.8% bonus for smoothness. Incentive pay for density, voids, VMA and asphalt content are calculated separately. There is a 50% weighting factor for density, 20% for voids, 20% for VMA and 10% for asphalt content. The maximum incentive for all these items also is 5%. Pike achieved a 2.2% bonus for HMA properties.

Despite a very rainy summer, MaineDOT opened I-295 south to traffic on June 10, approximately 20 days ahead of schedule, thanks to 16-hour workdays and a seven-day-a-week schedule, including holidays. Over 150,000 work hours were spent on this project.

MaineDOT’s highest priority was to ensure the safety of motorists, residents of alternative Rte. 201 and work crews. The decision to completely close the highway helped to achieve safety by allowing multiple crews to work without traffic at multiple locations along the 18-mile stretch. It also was a safer option for motorists, since they would not be distracted by multiple work zones along a major highway.

During the project there were no injuries on the jobsite, and traffic remained smooth on the designated alternative routes throughout the summer. Historically, Rte. 201 averages about five reportable crashes from June 15 through Aug. 31. During the project, there were no reported crashes.

MaineDOT Commissioner David Cole said the project “was a great success and underscored the reasoning to completely close the road to safely, quickly and effectively complete the work. We are extremely pleased with the quality, the teamwork and the early opening of this challenging project.”

About The Author: Hanley and Lane are with the Maine DOT, Augusta, Maine.

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