LAUSR

Abstract The blister test was aimed to develop and establish a simple, partial and reliable laboratory adhesion test method for direct measurement of the adhesive bond strength of bitumen and aggregate. Blister test was conducted by a device manufactured locally to measured bond strength of asphaltic material. Materials that used in this work were asphalt and aggregate. The local asphalt cement was obtained from Durah refinery, south–west of Baghdad .The aggregate used for comparison was limestone. This paper presents the development of pressure–loaded blister test and apparatus to measure the adhesion of asphaltic materials. The blister test provides the interfacial fracture energy, which is related to the adhesion strength. In this test air is injected at the interface between the substrate (aggregate disc) and adhesive layer (asphalt) to create blister. The air pressure and blister height were measured as function of time. By using two parameters, the interfacial fracture energy is calculated. In this paper was found that the energy required to displacement the asphalt binder increased with time until failure (adhesion failure) due to loss of adhesion between aggregate substrate and asphalt binder and also the required energy to failure decreased with increased binder thickness.