Sensor Technology for Decision Support of Spring Load Restrictions

Abstract

Spring load restrictions (SLR) are commonly used as a pavement preservation strategy in cold regions. Implementation of SLR has been found to bring about significant economic benefits by extending the pavement service life. Monitoring the degree of soil freeze-thaw status is crucial for making sound decisions on SLR implementation. Current tools to assist this decision are limited; they are unreliable and unable to provide timely data. As a result, the decisions on starting and ending of SLR, as well as the magnitude of load restrictions, are highly subjective. There remains room to optimize the benefits of this important transportation policy. A sensor and analysis method based on the time domain reflectometry (TDR) principle was developed that can accurately measure the degree of soil freeze-thaw status. Interesting results were obtained by using this technology to study the effects of freeze-thaw on soil mechanical behaviors. This sensor technology can assist in the implementation of SLR by (a) helping set the duration of SLR from accurately determining the degree of soil freeze-thaw status and (b) optimizing the level of road restrictions to optimize the cost and benefit between pavement preservation and freight industry. A field implementation of this technology is being conducted at Mn/Road, the world's largest and most comprehensive outdoor roadway laboratory.