Effectiveness of two reflection crack attenuation techniques.

PDFTech ReportCDOT-2015-10CDOT-DTD-R-2015-10Reflection crackingBituminous overlaysPavement interlayersAsphalt pavementsConcrete pavementsPavement distressSubbase (Pavements)Subgrade (Pavements)Service lifeColoradoColorado. Dept. of Transportation. Applied Research and Innovation BranchShuler, ScottColorado State UniversityUnited States. Federal Highway AdministrationUS Transportation CollectionAsphalt overlays are one of the most common tools for rehabilitating existing asphalt and concrete pavements.However, the performance of new overlays is often jeopardized by the cracking distress in the existingpavement. This existing cracking propagates, or reflects, through the new overlay to the surface of the newoverlay. The rate at which this reflection cracking propagates to the surface is a function of overlay thickness,crack severity, traffic loading and subgrade or subbase support. Once reflection cracks appear on the surfaceof the new pavement, water and debris can enter the subbase and subgrade which can affect pavement strengthand reduce the life of the overlay. Therefore, reducing the rate at which these reflection cracks propagate tothe surface of the pavement is desirable in order to lengthen the time between rehabilitation projects or cracksealing operations.Various methods have been used in past decades in an attempt to reduce the rate of reflection crackpropagation. These include geosynthetic membranes and asphalt stress absorbing interlayers.This study compares performance of a grid reinforcing system, a polymer modified asphalt-rich interlayersystem and control pavement test sections.After five years of performance monitoring differences between the attenuation systems and the controls haveappeared