A paper mill in coastal Maine made a decision in September, 2006, that a hard surface was necessary in a yard area where new process improvements were being installed. Like many newer industrial processes, it was important to keep the raw material feed areas as clean as possible and free from ground contamination. A hard surface would be necessary to keep the new equipment in a clean environment to improve the operating efficiency and lower maintenance costs. The resulting design called for construction of 75,000 square feet of pavement for this purpose; however, with winter approaching time was an important factor.
The contractor for the project (Lane Construction Corp.) approached the Project Engineer (Woodard and Curran, Bangor, Maine) to consider the idea of using Roller Compacted Concrete (RCC) for the pavement area. They knew they needed to build the largest pavement area possible for the lowest cost, and that it had to be constructed quickly. RCC has been used in many industrial applications, so the strength and durability of the concrete was well known, but for this project it had the additional advantage of allowing for rapid construction. And, given the lower cost of RCC, they would be able to pave 100,000 square feet instead of the original plan for 75,000 square feet.
The pavement was designed for heavy equipment and truck loading, resulting in a nine-inch thick concrete slab being specified. The site conditions consisted mostly of organic soils with some gravel and clay mixed in. This unsuitable material was removed and replaced with approximately two feet of well-draining gravel that served as an excellent base for the concrete pavement.
The concrete was mixed using an on-site ARAN pugmill and a blended cement furnished by Ciment Quebec Inc. that contained seven percent silica fume. This type of blended cement is popular in eastern Canada and Maine because of its high durability in freeze-thaw environments. The RCC mix consisted of:
- 1,771 lbs/cy of ½ in. NMSA crushed stone
- 1645 lbs/cy of sand
- 510 lbs/cy of blended cement
- 197 lbs/cy of water
- 20.3 oz/cy of Grace Daracem 65 water reducer
Paving was completed using a Vogele 2100 high-density paver that contained one tamping bar and two pressure bars in a variable-width screed. Excellent compaction was achieved by the paver, with very little subsequent rolling required. SEM, Quebec City, Quebec, performed the mix design and quality control. Field specimens were tested at seven days with an average flexural strength of 993 pounds per square inch (psi), and average compressive strength of 6,828 psi. Strengths of field specimens at 28 days were almost 30 percent higher than the results at seven days.
Vogele high-density paver and density testing with nuclear gauge
Pavement construction was in early November, right at the end of the construction season. Even though this was the first RCC paving project for Lane Construction, the 2,100-cubic-yard project was completed in two days.
Mike Atherton, Lane’s project engineer said, “We have been thoroughly impressed with the constructability, low cost, and high performance of RCC”.
Rolling and curing operations during construction
Adjacent to the end of the pavement area the contractor also placed an eight foot wide strip of pervious concrete, using conventional construction methods. This will capture the surface water draining off the RCC pavement in a trough area where equipment will operate. As an experiment, Lane Construction also placed some pervious concrete in a test area using the Vogele high-density paver, and found that the placement went very well. They were concerned that the paver may result in the pervious concrete being overly dense, but were pleasantly surprised when they measured 26 percent voids in the pervious material after the placement.
The engineer, owner, and contractor were all pleased with the results from their first-time experience with RCC pavement. The high-strength pavement will provide an operating platform with excellent durability under harsh conditions. In addition to the performance and cost benefits, the time savings resulting from the project was also impressive.
Travis Noyes, of Woodard and Curran, said, “The ability for the entire project team to develop a design, bid the project, and build it within budget using only two days of construction put the project literally months ahead of schedule.
RCC pavement after construction
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