Assessment of Asphalt Concrete Reinforcement Grid in Flexible Pavements

This report investigated the application of accepted methods of pavement structural evaluation to independently assess the potential structural benefit of asphalt geogrid reinforcement of an operational flexible highway pavement. The asphalt interlayer consisted of an elastomeric polymer coated fiberglass grid with an open configuration. The reinforcing grid was installed in the asphalt layer during construction of a maintenance overlay and has been subjected to trafficking for several years. The structural evaluation included a geotechnical investigation and nondestructive testing using a falling weight deflectometer. Field testing was conducted when both air temperatures were above 50°F and no recent precipitation events had occurred. Standard testing methods were applied during the field data collection and back-calculation procedure. The back-calculation results showed no clear quantifiable benefit from including the reinforcing grid in the asphalt layer, but this study developed a methodology to test and evaluate in situ flexible pavements with asphalt grid reinforcement. The authors recommend that a future structural evaluation be completed to monitor any changes in the pavement’s performance.