ABSTRACT
This paper describes a laboratory investigation into crack propagation in High Modulus Base (HMB) materials. The Compact Tension (CT) test has been adapted for use with bituminous materials. Particular attention is given to the development of a procedure to measure crack length using a remotely controlled digital camera. A standard fracture mechanics approach has been used to calculate the Mode I stress intensity factor and the Paris law has been used to describe the rate of crack growth. Results indicate the sensitivity to applied stress increases with decreasing binder penetration and decreasing temperatures (i.e. increasing binder stiffness modulus). Results also indicate that there were large differences between the performances of different mixtures. Differences in crack propagation rate of a factor of 10 or more were common, with nominally similar grade binders.
