Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/86539
suited for network-level pavement structure evaluation. Network-level GPR pavement structure assessments have been carried out at the statewide level, as well as by various local agencies and municipalities. At the network level, GPR is now being used for network segmentation into relatively uniform pavement structures, for data inventory input into a pavement management system (PMS) database, and for layer thickness detail for use with network level FWD evaluations. GPR won't replace the FWD. For example, Oklahoma DOT has been implementing GPR measurements as part of its ongoing efforts in pavement management to improve its decision making process through enhanced knowledge of its pavements' structural capacities. Previously, Oklahoma's PMS utilized only surface distress data to identify deficiencies at the network level and recom- mend appropriate treatments. More recently, the state has been acquiring pavement structural condition data using a combination of FWD and GPR measurements on its 2,765 centerline-mile, non-toll NHS system. Oklahoma DOT uses GPR to reduce the number of cores required, to identify changes in the pavement structure, and to provide informa- tion for overlay design, says Maser. "The combination of GPR and FWD data is being exploited by other agencies to identify underlying conditions and to support pavement rehabilitation design," he adds. "In 2006, Montana DOT acquired a combined GPR/FWD system, and since then has been using the system at a network level to obtain more accurate characterization of pavement structural properties by combining GPR layer thickness data with FWD data. UST [is] ... engineered to detect and evaluate internal reinforced concrete defects New on the horizon is ultrasonic testing, the MIRA process. Using ultrasonic shear-wave tomography (UST) technology, it's a low-frequency (20 to 100 kHz) phased array ultrasonic system engineered to detect and evaluate internal reinforced concrete defects such as honeycombs or voids, and is useful for large concrete structures like bridge components. Write 147 on Reader Service Card or visit www.betterroads.com/info Better Roads October 2012 25