“Computational Civil Engineering - "Intersections" International Journal

“Computational Civil Engineering 2005”, International SymposiumIaşi, România, May 27, 2005The study of geocomposite influence on wearing course asphaltmixture behavior at permanent deformationElena Diaconu, Carmen Răcănel1 Prof., Ph.D., Road Department, Tehnical University of Civil Engineering, Bucharest, Romania2 Assoc.Prof., Ph.D., Road Department, Tehnical University of Civil Engineering, Bucharest, RomaniaSummaryFollowing the research, it was demonstrated that can be used the octahedral shearstress theory to analyze the premature deformation that appear in pavementasphalt layers.This paper has an intention to study the influence of the place of geocompositeunder the asphalt layer on the values of octahedral shear stress ratio.To solve this problem we use the material characteristics obtained in laboratorfrom triaxial test and an analyze of stresses and strains state in pavement structure,with and without geocomposite obtained using an elastic linear software.The conclusion that can de drawn is the following: the placement of geocompositelead to smaller octahedral shear stress ratio values in wearing course than in thecase of structure without geocomposite.KEYWORDS: geocomposite, asphalt mixture, permanent deformation1. INTRODUCTIONOne of the most important distresses that can appear in a flexible pavementstructure is the permanent deformation. This kind of distress has considerableeffects on circulation comfort and safety and for this reason the asphalt mixturethat can become deformed under traffic and temperature, must be taken intoaccount.During the time it was demonstrated that the octahedral shear stress ratio (OSSR) isa very important parameter from pavement deformation point of view and gives thepotential for rutting of mix. The OSSR (equation (1)) is the ratio of the criticalinduced octahedral shear stress in the pavement layer (τ oct ) to the octahedral shearstrength of the material (τ oct, strength ):