Structural health monitoring of pavement assets through acoustic signature

The assessment of the structural and functional pavement condition is nowadays fully machine based and non-destructive equipment does cover all the data input required for a modern PMS approach. A Multi-Laser Vehicle is capable of real time continuous traffic-speed measurements of condition data regarding cracking, ravelling, rutting, roughness, macro texture and road geometrics in a single run using high-speed line-scan cameras for an automated assessment. The system of the Multi-Laser Vehicle equipped with a Laser Crack Measuring System (LCMS) is the most promising development in 3D camera technology with a progressive improvement of capabilities and quality. This paper discusses the results of the equipment used as well as the accuracy and repeatability achieved. Shown is as well the continuous measured macro texture based on the Mean Texture Depth (MTD) as index using the LCMS device in addition to the automated crack detection. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the Sand Patch. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in comparison to the non-consistent wind-screen surveys and manual rating of collected images. In addition to the MTD the sampling of rutting has been validated against the multi-laser profiler approach as well as the International Roughness Index (IRI) based on Inertial Motion Units (IMU’s) attached to the LCMS sensors.