Abstract
Rutting potential in asphalt concrete pavements (ACP) over both flexible (granular), and rigid portland cement concrete (PCC) pavements is investigated. A detailed analysis of the influence of ACP mixture stiffness, stiffness ratios between the ACP surface and the supporting base, ACP layer thicknesses, surface shear, realistic tire contact stresses, and degree of interlayer bonding is presented. The result of the analysis is presented in terms of octahedral shear stress contours. Over 250 plots of octahedral shear stress contours for a wide variety of structural conditions are presented in Appendix C of the Ameri-Gaznon and Little 1988. The triaxial shear strength test and the octahedral shear strength calculated from the parameters of Φ' and C' derived from the triaxial test are used, in concert with the maximum octahedral shear stress within a selected pavement structure and for selected conditions of interlayer bonding and surface shear, to develop a ratio of induced octahedral shear stress to octahedral shear strength. This ratio is used to evaluate deformation potential for a wide variety of mixtures under a wide variety of conditions. More traditional creep testing and cyclic permanent deformation testing are also presented and the modified ILLIPAVE finite element computer model is used to predict permanent deformation in these mixtures under specified pavement structural, climatic, and traffic conditions. Four ACP overlays over PCC bases were evaluated and the data were used as a link between the field and theory to develop a first approximation of critical octahedral shear stress ratios. A long-term creep test, performed at a higher level of stress than is normally used in the more traditional creep test, is presented as a potential laboratory test procedure to differentiate among the permanent deformation potentials of asphalt concrete mixtures. The combination of high stress level and long-term loading (eight hours) may be necessary to adequately differentiate among mixtures as to rutting potential. This technique, together with triaxial testing (octahedral stress ratio approach), is presented as the preferred analysis technique.
Ameri-Gaznon, Mahmoud (1989). Permanent deformation potential in asphalt concrete overlays over portland cement concrete pavements. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -991972.