As with many other New England states, Maine 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 recently suffering from accelerated deterioration due to alkali silica reactivity (ASR).
ASR is a chemical reaction between the alkali in the cement and silica in certain aggregates. A gel is formed that attracts available water in the concrete, resulting in cracks in the aggregate and the concrete. This reaction can go on until the concrete disintegrates, causing structural failure.
After evaluating the best way to approach the issue, MaineDOT recommended closing the 18-mile stretch of southbound I-295 from Augusta to Topsham during the peak season of Maine's $10-billion tourism industry.
Given Maine's short construction season and the potential impacts on the economy, a project timeline of about 2-1/2 months was established. MaineDOT offered a $2-million incentive for early completion, a penalty for delays, and awarded the contract to Pike Industries, Inc. of Westbrook, ME.
The two-phase project included putting down 181,000 tons of asphalt, rebuilding five bridges and installing 7 miles of guardrail. The first phase was constructed under traffic on the 4-mile southern section from Topsham to Brunswick. The second phase was 18 miles long from Topsham to Gardiner.
The scope of work included 245,000 square yards of concrete milling; 27,500 square yards of slab removal; 245,000 square yards of concrete rubblizing; 165,000 square yards of shoulder pavement removal; 243,000 linear feet of inslope 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.
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 Corporation of Pittsfield, ME. Earthwork subcontractor Shaw Brothers of Gorham, ME, removed concrete that subcontractor RMI of Tulsa, OK, had previously rubblized and regarded 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, ME, installed new rail. All work on the 4-mile section was completed, under traffic, in time for the full closure of the north section.
The next step saw concrete milling contractor Swank of New Kensington, PA, removing 3 inches of concrete from the surface of the slabs. The waste concrete was either deposited directly onto the shoulder or trucked to an on-site recycling area where Pike Industries' portable crusher processed all removed concrete into sized shoulder aggregate. One hundred percent of the waste concrete was used as base material for the shoulders. Milling the 3 inches of concrete not only provided shoulder aggregate but also reduced the area of in-slope regrading required.
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 closely followed Swank's cold planers. RMI rubblized the remaining 6 to 7 inches of concrete to MaineDOT specifications of 6-inch maximum size. This entire process was completed in less than two weeks.
Shaw Bros crews installed 775 weep drains adjacent to the concrete slabs, prior to milling and rubblizing, to assure 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.
Within a week, Pike paving crews began echelon paving of the 3-inch layer of "rich" base. This mix was a standard 19-millimeter Superpave design with an additional 1-percent asphalt added to provide a superior bond to the rubblized concrete surface.
The 8-inch HMA buildup consisted of the rich base, another 3 inches of standard 19-millimeter base, and intermediate and final layers of 1.5 inches of 12.5-millimeter mix. The 12.5-millimeter mixes for mainline contained Polymer Modified (PMA) PG 70-28 liquid asphalt. The standard asphalt used in Maine is PG 64-28. Two 1.5-inch layers of 12.5-millimeter mix without PMA 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 1/4-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 rubberized asphalt joint sealer to longitudinal pavement joints. Surface Preparation Tech of Mechanicsburg, PA, installed rumble strips, and L&D Safety Markings, of Barre, applied striping.
MaineDOT adopted QC/QA specifications and the Superpave Mix Design and Testing system in the mid 1990s. Pike Industries utilized over 12 QC technicians in both the plants and the field to assure maximum performance. Pike produced their own PG 70-28 PMA 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.
Despite a very rainy summer, MaineDOT opened I-295 South to traffic approximately 20 days ahead of schedule, thanks to 16-hour workdays and a seven-days-a-week schedule, including holidays. Over 150,000 person-hours were spent on the project. The new pavement is expected to last more than 20 years.
The project was 90 percent funded by the Federal Highway Administration and impacted over 1,500 individuals in the form of employment, with over 90 percent of the work performed by Maine-based companies.
Some information for this article was supplied by Technical/Construction Report for Roads and Bridges Magazine.