The Variation of Early Water Contents in Environment-Friendly 4S Pavement System Foundation

The need to develop a new environment-friendly pavement system of excellent structural performance as well as high user functionality resulted in the concept of 4S pavement, which stands for Safety, Silence, aeSthetics, and Satisfaction for the users. Unlike existing permeable/drainable pavement, 4S pavement uses a cement-treated base (CTB) of low shrinkage and permeability/impermeability to restrain the reflection crack while reinforcing the structural strength of the pavement. This study employed the experimental construction of environment-friendly 4S permeable/drainable pavement system in the field to investigate two properties: 1) the change in gravimetric water content of the subgrade in response to the rainfall, and 2) the permeability pattern pursuant to the rainfall treatment method for the cross sections. To examine the behavior of water contents of the pavement subgrade, this study compared and analyzed the changes in water content of the subgrade layer and the saturation rates obtained from a Time-Domain Reflectometer (TDR). The TDR measurement of the subgrade water content revealed that the water content of the cross section constructed of permeable asphalt pavement (AP) with permeable CTB responded sensitively to the rainfall, owing to voids in the surface and base, and that moisture evaporation progressed very rapidly in that section compared to the other cross sections. TDR measurement also revealed that the saturation reached 100% for the cross sections of regular asphalt and permeable AP/impermeable CTB after about 10 months. According to the comparison between deflections obtained from the Falling-Weight Deflectometer (FWD) test and saturation rates, more stable pavement systems can be developed using a high-stiffness layer, even though the subgrade loses stiffness with the increase of moisture contents.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; Photos; References; Tables;
  • Pagination: 26p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01046286
  • Record Type: Publication
  • Report/Paper Numbers: 07-2053
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 6:45PM