This post is second in a series about how research supports innovation at UDOT. Many in the transportation community and the general public are familiar with UDOT’s method of building bridges off-site and then moving them into place. Other important innovations garner less attention. See the first post here.
UDOT’s innovative pre-cast pavement panels speed up concrete road repair.
Precast concrete elements are often used for bridge girders, decks or MSE walls. But using pre-cast panel systems to repair or build pavement is not yet common. UDOT Research Division has partnered with FHWA Highways for Life to develop and demonstrate a design for a precast pavement panels, and so far, “they seem to be working very well,” says UDOT Research Project Manager Daniel Hsiao who oversaw panel testing and design.
The innovation is in the speed of construction, and the non-proprietary design. Using a cast-in-place method involves closing lanes and waiting for concrete to cure before traffic can travel on the pavement. With pre-cast pavement panels the cure time takes place off site, so traffic lanes can be reopened soon after installation.
The unique design specifies leveling bolts that are commonly used in bridge deck construction. After placement, the bolts are turned against steel panels on the sub-base to achieve correct elevation. Four bolts are placed in each panel during the casting process. Six grout ports are also included in each panel. Using the bolts also means that traffic lanes can be open before the grout is fully cured.
The panels are also designed to be a standard size, 12 by 12 feet square and 9 inches thick. A standard panel size helps minimize construction costs and simplify installation. The panels are reinforced with steel rebar to support lifting the 17,000 pound panels.
Because the design is non-proprietary, “anybody can use it,” says Hsiao. The non-proprietary aspect helps support a competitive bidding environment, which conserves limited funding.