Fatigue crack growth in asphalt and asphalt-interfaces

Fatigue cracking due to traffic load is a major factor in road damage. Therefore, durability and lifetime prediction of roads plays a substantial role for road maintenance and cost planning. This paper reports a study of fatigue crack performance of solid asphalt and asphalt–asphalt interfaces by means of the wedge-splitting test. Instead of beams and the three- or four-point bending test, the wedge splitting method was used for the first time to observe crack growth on bituminous drilling cores. Samples of solid asphalt and samples with asphalt-interfaces were tested. One group of asphalt interfaces was untreated and the other was sandblasted before spreading the top layer during manufacturing. Due to the temperature dependency of material properties of asphalt, the tests were performed in a compact climate chamber at −10°, 0° and +10 °C. The challenge of determining the crack length and the crack tip were detected with an optical measurement system and picture analysis after testing. The results prove that the wedge splitting method is a highly practicable and repeatable method for crack growth testing of bituminous materials.