Comparison of Test Sections of Low-Volume Roadways Reconstructed with Conventional Techniques and Full-Depth Reclamation

Abstract

Three test sections were established in 2005 along a portion of the Kancamagus Highway in New Hampshire, where different reconstruction techniques were used: conventional (box-cut) reconstruction, full-depth reclamation (FDR), and FDR with cement-treated base. During the 2005–2006 winter and spring, elevation surveys were conducted to examine frost heave behavior. In 2006, those three test sections were folded into a larger research project sponsored by the New Hampshire Department of Transportation and the U.S. Department of Agriculture's Forest Service. For that project, extensive falling weight deflectometer (FWD) testing was conducted during the 2008 spring-thaw period to investigate variations in pavement stiffness that result from seasonal changes in temperature and moisture. An additional elevation survey was conducted in July 2009 to check for rutting in the wheelpaths. Results of this research suggest that FDR provides an economical and environmentally friendly alternative for reconstruction of low-volume roads. The 2005–2006 data show that the two FDR test sections exhibited more frost heave than the box-cut section, presumably due to frost-susceptible subgrade soils that remained in place in those sections. However, the 2008 FWD data suggest that the overall stiffness of all three test sections was similar. Five years after initial reconstruction, survey data indicate that little to no rutting has occurred. Visual inspection revealed some cracking, with most of the observed distress attributed to thermal cracking on all three test sections.