A simplified thickness design procedure for pavement structures constructed with asphalt mixes, dense-graded emulsified asphalt mixes, or cement-modified emulsified asphalt mixes is described. Elastic layer principles are used in the development of the procedure. Two critical strains--the horizontal tensile strain at the bottom of the treated layer and the vertical compressive strain at the surface of the subgrade--are examined in determining the proper pavement thickness. Allowable values for tensile strain are based on laboratory fatigue tests, with consideration given to the slower crack propagation time encountered in the field. Vertical subgrade strain criteria developed from field observations of pavement behavior have been selected to minimize surface rutting caused by overstressing the subgrade. Environmental considerations, in particular, the effect of temperature, the curing effect of emulsified asphalt mixes and the effect of frost on subgrade strength, are considered in the design. A relationship is proposed showing the important effect of the volume of air voids and asphalt in a treated mix on its fatigue behavior and, hence, the thickness requirements for the pavement structure. The paper contains a step-by-step outline of the design procedure for the practicing engineer to follow in determining pavement thickness requirements. A design example is included with the necessary work sheets to show the proper use of design charts, graphs, and equations. The procedure does not require the use of computers. However, simple computer programs written in BASIC have been developed to eliminate the tedious hand calculations described in the paper. These programs cover the design of pavements made with asphalt, emulsified asphalt, or cement-modified emulsified asphalt mixes. /Author/

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: p. 424-456

Subject/Index Terms

Filing Info

  • Accession Number: 00170229
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM