ROADS & BRIDGES/ARRA RECYCLING AWARDS: Open at 9
Contractor adjusts to multiple sections on Bumby Ave.
Stores want their aisles set up a certain way, even if they are not the ones showing any product.
So when the time finally came to reconstruct Bumby Ave. in Orlando, Fla., the city was careful not to stray from the original floor plan, which called for breaking up the 4,800-linear-foot project into nine sections—the closest resemblance to aisles at a road site.
“We actually gave them a value-engineering proposal to do it in effectively three phases, but [the city of Orlando] was very hesitant to do that because they felt like they had committed to a particular traffic-control plan in the original bid process, which they had sold to the local businesses,” Jeff Roberts, president, Roadway Management Inc., told Roads & Bridges. Roadway Management is part of Hubbard Construction Co., which was the prime contractor on the Bumby job. “They were afraid that any variation from that phasing plan was going to lead to some sort of legal action if they had been inconvenienced at all.”
Hubbard Construction Co. stayed between the lines, but simply could not contain success as the Bumby Avenue project won a 2011 Roads & Bridges/Asphalt Recycling and Reclaiming Association Recycling Award in the Full-Depth Reclamation category.
“I think if Bumby had not gone well, the city of Orlando would have seriously reconsidered doing any more [FDR] for a while,” remarked Roberts. “They have bought into it. They like it.”
“It was the first time that I had actually been involved with a reclamation project, but it went really well,” Paul Crouter, project manager for the city of Orlando, told Roads & Bridges. “Just being able to close connecting roads for brief amounts of time while they were doing the grading and reclamation was extremely beneficial. We did not have a lot of shutdown.”
Soil and lime
Bumby Avenue had been seriously on hold for quite some time. A victim of a lack of funding, the shopping route was having a hard time keeping it together. Block cracking and potholes were prevalent, and nothing was planned in the immediate future until the state of Florida stumbled across a bundle of cash for shovel-ready projects. The Bumby Avenue FDR project was funded entirely by American Recovery & Reinvestment Act money, and the full-depth reclamation process saved Orlando $800,000.
“The road was on the verge of really slipping away on them,” said Roberts.
“It was poor,” added Crouter. “It had been resurfaced many times with different sections of the road having different sub-bases.”
The road consisted of two sections: soil cement and lime rock. The soil cement sections consisted of six of the project’s nine phases, with the lime rock section taking up the other three. According to Roberts, the soil cement work was broken down even further (two three-phase portions) due to the location of major intersections and a dairy, which produces truck traffic at all hours of the day. The city of Orlando wanted all the work to be done during daylight hours, and that decision catered more toward an old historic district than the strip of businesses.
“They simply did not want the noise at night,” said Roberts.
However, effective phasing was especially beneficial for local businesses leading up to the holiday season when work concentrated on the residential side of the project.
A Wirtgen Reclaimer WR2500S was the first on the scene, pulverizing 11 in. of existing pavement and base. When pulverizing was complete, 3 in. of material was removed to match the level of existing curb and gutter, and the remaining 8 in. of pulverized material was stabilized with asphalt emulsion material. Mariani Asphalt, Tampa, supplied the SS 1h emulsion. A Hamm HD+ 120 VO handled compaction duties and helped establish the template that included a 2% cross slope.
Dealing with soil cement can be quite difficult in Florida. According to Roberts, soil cement tends to be extremely hard because the mix design usually calls for 7-8% cement, which causes a lot of block cracking.
“Sometimes when we get into these soil cement bases it is like concrete. It can be really rough on the teeth of the reclaimer,” said Roberts. “We have had experiences with soil cement where you had to go through the soil cement into the underlying subgrades just to get a product that would mix and work without basically melting down the drum head on that reclaimer.”
There were two mix designs (one with cement, one without) for the soil cement and lime rock sections, and the city of Orlando elected to go without the use of cement. For the soil cement section, the design without cement called for 2% of the SS-1h emulsion based on the calculated pounds per cubic foot, which amounted to 1.44 gal/sq yd of emulsion required for the section.
The lime base section was handled the same way, but called for a slight variation in the mix design. Without cement, the design called for 1.51 gal/sq yd of the SS-1h emulsion.
Quality-control testing produced the following results for phases 1 and 2: 111 field density, 4,500 Marshall Stability, 1,800 Marshall Wet Stability and 0-40% retained wet density. Phase 3 had a field density of 119, 5,500 Marshall Stability, 2,500 Marshall Wet Stability and 45% retained wet density.
Once the base was able to cure for 48 hours, crews came in to lay down a 3-in. Superpave hot-mix asphalt (HMA) overlay in two lifts (9.5 and 12.5 mm). A Gencor asphalt plant located 9.7 miles from the jobsite supplied the material. A Volvo PF6110 tracked asphalt paver placed both mats at 300ºF. A RA 1000 asphalt binder was used for the 12.5-mm lift and a RA 1100 asphalt binder for the 9.5-mm lift. The mix contained 30% reclaimed asphalt pavement (RAP). For the larger sections of work, the roller pattern consisted of a Hypac BW9AS static roller serving as the breakdown roller, a Hypac C530A serving as the intermediate roller and a Hamm HD+ 120 VO (articulated tandem roller with oscillation) handling the back roller duties. The Hamm HD+ 120 VO served as both the breakdown and back roller in the smaller sections. Due to the sensitive environment, rollers were not allowed to operate in the vibratory mode.
Hubbard maintained 94% density throughout the project, and recorded zero deficiencies with a rolling straight edge.
An abandoned gas line was discovered during construction. According to Roberts, the city of Orlando quickly came in, removed a portion of it and encapsulated the rest. Crouter said once Hubbard started its base, mixing it revealed voids in a sanitary line.
“It was probably the vibration from the reclamation that might have had a little bit to do with the collapsing, but this was a pipe that needed to be repaired anyways,” he said.
Hubbard also updated sidewalks to meet ADA standards, added pedestrian poles and signals at various crosswalks, replaced signalization loops and added a bike lane. R&B
I-81 in Va. claims CIR award
The I-81 pavement-recycling project in August County, Va., also claimed a Roads & Bridges/ARRA Recycling Award in the Cold In-Place category. The work was featured in the September issue (see Everything in green, p 48).
It is the first project in the U.S., and second in the world, to utilize full-depth reclamation, cold in-place recycling and cold central-plant recycling. Roanoke, Va.,-based Lanford Brothers Co. was the prime contractor, and after it was revealed that the existing subgrade had deteriorated to the point of causing damage to the friction course, subcontractor Slurry Pavers Inc. stabilized it with 5% lime kiln dust to a depth of 12 in. Lanford milled the top 10 in. of asphalt from the right-hand truck lane and transported the material to a cold-mix plant just off the interstate, where it was foam-recycled for immediate placement as a flexible base course.
In the second phase of the project, subcontractor Reclamation Inc. performed in-place foam recycling in the left-hand passing lane. For this work, the top 2 in. of pavement was milled off, followed by cold in-place recycling of the next 5 in.
“This project saved Virginia DOT and taxpayers millions of dollars by reusing existing resources,” said Ken Lanford, president of Lanford Brothers
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