During the preliminary stages of design for this runway pavement project, Benesch developed and evaluated seven different pavement section alternatives, ranging from a new minimal four-inch mill with new asphalt overlay to complete reconstructions starting from the subgrade up. The costs for each option were evaluated not only based on initial cost, but also on a 20-year life cycle accounting for the routine maintenance needed on asphalt and concrete surfaced pavements.
The final selected option was an economical—and green—solution formulated by Benesch which reutilized most of the existing pavement structure materials. From the pavement section selected, Benesch ultimately designed the project to first mill off the top eight inches of the existing pavement structure. The millings were then screened (to a required gradation) and stockpiled on-site for re-use during the project. Then the remaining existing PCC concrete was rubblized and seated in order to create a granular base course out of the existing PCC pavement. A test section was performed during the rubblization process to ensure the size of the rubblized material met the project specifications.
After the existing concrete was rubblized and seated, a two-inch thick leveling course of the screened millings was added on top of the rubblized base course. The millings leveling course was added as a layer that could be trimmed to grade by the contractor during preparation operations for concrete paving.