Effects Analysis of Fatigue Cracking and Permanent Deformation Models on Pavement Mechanistic Design

Fatigue cracking and permanent deformation are two important criteria for pavement mechanistic design. In pavement mechanistic design assumes tensile strain for fatigue cracking at the bottom of the asphalt layer but for overlay mechanistic design it assumes either at the bottom of the asphalt or overlay layer. This paper determines pavement fatigue life using tensile strain at the bottom of the asphalt layer and permanent deformation life with pressure strain under subgrade layer. KenLayer software is used for analysis of pavements with different thicknesses (thin, mid and thick) on three types of subgrades (strong, moderate and weak). The results of analyses and comparisons determine critical criteria in different types of pavements permanent deflection and fatigue cracking graphs for pavement design, are also presented here.