Evaluation of Lightweight Non-Contact Profilers

摘要

Pavement smoothness was recently identified as the most significant factor the motoring public uses to judge the quality of our Nations roadways. A new generation of lightweight profilers has recently been developed, which have the potential of providing nearly instantaneous smoothness measurements, providing contractors with a tool to identify and address process control issues promptly and cost effectively. The new technology was co-operatively evaluated by a team of Purdue University and Indiana Department of Transportation (INDOT) researchers to assess the repeatability and reproducibility of the devices, as well as the potential for their use in Indiana. A successful field test was conducted, with four ASTM Class I lightweight profilers performing five replicate measurements at each of six sites; three hot mix asphalt (HMA) and three portland cement concrete (PCC) sites. Smoothness data was reported in terms of International Roughness Index (IRI), PI-0.0” blanking band and PI- 0.2” blanking in inches/mile. The field test data showed good repeatability and poor reproducibility in terms of the smoothness indices reported, the profiles generated and the identification of must-grind locations. The performance of the lightweight profilers was adversely affected by extreme geometric conditions at some sites. The precision of the devices was determined in accordance with ASTM standards and also revealed good repeatability but poor reproducibility. The reproducibility of the devices was so poor that it was recommended that INDOT retain its current smoothness specification which relies on the California Profilograph until the lightweight profiler technology is refined. Smoothness specifications of other states were reviewed in light of their application to lightweight profilers and a draft smoothness specification based on lightweight profilers was developed for INDOT. It was further recommended that the draft specification not be implemented until the profiler refinements are achieved, but rather the proposed pay adjustment factors be evaluated over the coming construction season on a trial basis, such that when the lightweight profilers are refined an implementable specification will be available.