Crack growth behaviour in geosynthetic asphalt interlayer systems

Geosynthetic interlayers in asphalt systems have become a convenient technology for lifetime prolongation in road construction engineering. Durability and lifetime prediction analysis of such systems can be obtained by fatigue crack growth testing. In this paper, the fatigue crack growth properties of three different asphalt interlayer system groups with different interlayer functions: SAMI (=Stress Absorbing Membrane Interlayer), asphalt reinforcement and the combination of SAMI + asphalt reinforcement are reported. For comparison non-interlayer systems (reference) have also been tested. Instead of 3- or 4-point bending tests with beams, wedge splitting tests with drill cores from the field are used for analyzing the fatigue crack growth behaviour of these systems. Due to the temperature dependence of asphalt the tests have been performed in a climate chamber at -10 degrees C, 0 degrees C and + 10 degrees C. Crack growth propagation was determined visually. The results show that this new visual approach for evaluation of crack growth testing together with the wedge splitting test are practicable, reproducible and allow grading of geosynthetic asphalt interlayer systems.