To keep pace with continued growth and expanding market opportunities in 2017 and beyond, APM Terminals needed to expedite the expansion of its container facility at the Port of Mobile by 20 acres to boost its annual throughput capacity by nearly 50%.
Increased cargo volume at the port is being driven by larger vessels from East Asia transiting the widened Panama Canal, as well as the addition of new weekly container shipments from North Europe. New Walmart and Amazon import distribution centers currently under construction in Mobile will bring additional new business.
With the growing trend toward higher throughput volumes and heavier loads at the port, accelerated construction of a new 900,000 square-foot concrete pad was of paramount importance to provide more storage for the offloading of cargo and ensure goods were transferred through the terminal efficiently.
Based on speed of construction requirements, economic considerations, and need for long-term durability, the project team selected roller-compacted concrete (RCC) as the paving material for the new container storage yard.
The rigid monolithic paving plan called for 18-inch dual-lift construction (10-inch bottom layer and 8-inch top layer) placed on an 18- inch base of cement-treated soil.
The 5,000-psi strength RCC—a mix containing Type I/II Portland cement, river sand and limestone rock —was produced using an on-site continuous-mixing pugmill, which had the mixing efficiency needed to evenly disperse the relatively small amount of water used. The pugmill produced more than 300 cubic yards of RCC per hour, which was unloaded directly into dump trucks for delivery to nearby Volvo ABG high-density pavers on the job site.
“With RCC production volumes requiring 500 tons of cement per day, logistics planning and coordination were critical to ensuring a smooth paving operation,” said Don Carlisle, market manager for Holcim US, a subsidiary of LafargeHolcim Ltd. “To meet daily supply demands, Holcim US delivered three truckloads of cement per hour for seven straight paving hours with minimal delays.” Approximately 12,000 tons of cement for the RCC mix was sourced from Holcim US’ manufacturing plant in Theodore, Alabama, which is strategically located within 15 miles from the APM Terminal job site.
Paving the new container storage pad at the Port of Mobile was completed in only 26 working days. With cargo volumes rapidly increasing, there was not a lot of available container storage space to work with so portions of the new pavement were turned over to APM terminals as the job progressed and the specifications allowed. Paving width was 30 to 35 feet and RCC production rates were 1,500 to 2,000 cubic yards per 8-hour paving day. Daily on-site quality-control testing included casting cylinders for compressive strength and taking pavement cores to validate RCC depth and bond. Feedback from the owners and general contractor who have viewed the RCC has been overwhelmingly
positive. “Everyone was impressed with the speed of construction and high-quality pavement surface,” said TJ Peltz. “For the Port of Mobile and APM Terminals, the economic benefits of completing this fast-track project as quickly as possible were significant, which speaks volumes to the quality of the RCC pavement and planning by all people on the team.