Asphalt pavements are constructed with a mixture of materials that are continuously paved for a smooth surface and without the need for transverse expansion joints every few yards, which disrupt the ride. But it goes further than that. Because of how asphalt pavements are designed and constructed, as well as their intrinsically flexible nature, they can provide and maintain a greater level of smoothness than other paving options over time.1 Asphalt engineers are constantly innovating to ensure roads perform for the driving public today and into the future.
Asphalt pavements are built in layers, adding strength and increasing the road’s carrying capacity as each layer is placed. These are just a few examples of asphalt pavement technologies that ensure safety, performance, cost-effectiveness, durability, and sustainability:
- Asphalt overlays, which can range from a fraction of an inch to several inches thick, provide an economical solution to aging roads in need of preservation and updates.
- The asphalt industry uses Perpetual Pavement designs to build long-life asphalt pavements that never require major structural repairs. Instead, they require minor surface rehabilitation about every 12 to 15 years.
- Stone-matrix asphalt, open-graded friction courses, fine-graded surfaces and rubberized asphalt can help reduce highway noise by as much as 7 decibels.1
Asphalt pavement companies are constantly innovating within their operations. Finding ways to streamline operations, automate tasks and increase operating efficiency. These advances are ultimately used to reduce the bids on project contracts – when the competitive lettings take place.
- Fleet management systems with GPS track trucks ensure high-quality products and efficient operations.
- Intelligent construction technologies use GPS for grade control, infrared systems to aid compaction, and more.
- App-based technologies and artificial intelligence technologies improve operations and saving money.
Road Built for Super-Heavy Hauls to Louisiana Chemical Plant
International engineering and construction firm, Fluor, called on Barriere Construction to build an asphalt pavement that could handle transports weighing 25 times as much as a traditional semi.
By Chuck MacDonald
Most people who understand road-building know that a fully loaded tractor trailer can stress roads not constructed to sustain that weight. A recent project led by Fluor, an international engineering and construction firm, supervised the delivery of gigantic modules weighing 25 times as much as a traditional semi and four times as long. Some of the special transportation vehicles had 80 axles to support the weight for these massive loads.
To prepare the road for heavy hauls to the Sasol petrochemical complex in Lake Charles, La., Fluor turned to Barriere Construction, based in Metairie, La. This project, which represented the largest foreign investment in Louisiana history, provided many opportunities for Barriere to tackle new challenges while showcasing the innovative qualities of asphalt.
Westlake, La., is home to various refineries and chemical plants. Nearby access to the Gulf of Mexico for water transport and availability of cheap natural gas for plant operations make this area a no-brainer for these industries. Still, huge pieces of equipment, like the ethylene oxide wash tower and the ethylene cracker, needed to be transported a short distance by road, as Sasol had determined it safer and more economical to manufacture such equipment off site.
Jeanne Hornsbey of C.H. Fenstermaker & Associates in Lafayette, La. provided the engineering design, which called for the innovative use of asphalt to ensure the road would sustain atypical strain.
“I have been working on projects like these for 13 years, but never one of this magnitude,” she said.
“Sasol has done at least 1,500 of these massive shipments along the redesigned road, sometimes doing two or three a night. Some of the other large companies in the area are now using the heavy haul road as well.”
The 2.5-mile road was widened up to 62 feet to allow the modules (up to 317 feet long) to navigate a right-hand turn in the road. Barriere used 30,000 tons of asphalt for the road, with an additional 20,000 tons for paving inside the company gates. The project called for a foot of treated subgrade (combination of lime and cement), then 4 inches of asphalt base course. The next layer was 7 inches of level two asphalt binder topped by a 1.5-inch level 2F asphalt wearing course.
“We used a standard DOTD mix with a grey stone limestone aggregate that included some recycled asphalt,” said Tristan Wilson, Barriere senior project manager/estimator. Once each layer of the paving was complete, the road had to quickly be turned back to daily traffic, as approximately 8,000 workers at the Sasol plant use the road to commute; an elementary school is on the route as well.
According to Wilson, one of the biggest challenges was relocating 32 utility lines and providing for proper drainage. “It seems that every time we started the excavation, we would discover another utility line that we didn’t know about,” he added. Water issues demanded special care, especially since the road needed to be open for traffic during construction. “We used a 120-inch jack and bore to install the culvert while the paving was happening above. It took us several weeks to install and is 5 feet below the roadway.”
In addition to paving duties, moving utility lines, and handling water issues, the Barriere team moved traffic signals to accommodate the modules, some of which were 50 feet tall. “We installed rotating signal mast arms that held the traffic lights,” said Wilson. “By removing just a few bolts, we were able to move the signals out of the way, then reattached them after the modules had moved through the intersection.”
Working with stakeholders like Sasol, Fluor, the Louisiana DOTD, and local government required a lot of coordination from Barriere. But it was well worth the effort, as 200,000-man hours on the project were completed without a single recordable injury or lost-time incident. “We learned a great deal from the people with these large companies who manage projects all over the world,” said Wilson, adding that Barriere has incorporated some of the stakeholders’ practices into their own safety program.
Writer bio: Chuck MacDonald is a writer living in Annapolis, Md. He has been a frequent contributor to projects for NAPA and other organizations.
WSDOT (2012). “WSDOT Pavement Roughness (IRI) Report: 2010” in WSDOT Pavement Notebook. Washington State Department of Transportation, Olympia, Washington.