Revisiting Field Performance of Cold Central-Plant Recycled Test Sections at MnROAD Low-Volume Road

Abstract

In 2017 four test sections (test sections 133, 233, 135, and 235) containing a cold central-plant recycled (CCPR) layer underneath a surface treatment were constructed on the MnROAD low-volume road (LVR). Two types of CCPR mix designs were constructed: test sections 133 and 235 contained an emulsified asphalt; test sections 135 and 233 contained a foamed asphalt. Each CCPR mix design (foamed asphalt and emulsified asphalt) had two types of wearing surface layers (double chip seal and 1.5 in. HMA [hot-mix asphalt] overlay—thinlay) to create the four test sections. The rest of the pavement structure beneath the newly constructed CCPR was left in place and consistent throughout all four test sections with the remaining granular base over the existing clay subgrade. This paper presents a revisiting of the field performance of the CCPR test sections at the MnROAD LVR. To do this extensive field data was collected over approximately 3 years through visual distress surveys, and ride quality, rutting, and falling-weight deflectometer testing. Field study determined that both CCPR mix designs (foam and emulsion) performed similarly and the thinlay HMA layer outperformed the double chip seal in respect of rutting; but both surfaces are considered valid alternatives for future applications depending on the traffic volumes expected.