Semi-circular notched beam testing procedure for hot mixture asphalt

Abstract

The purpose of this study was to facilitate and improve the methodology used for hot mixture asphalt fracture evaluation and to establish a procedure to overcome the difficulty of preparation of hot mixture asphalt beam samples for fracture testing. This research investigated and compared the stress intensity factor (KIC) determined by two test set-ups: the semi-circular notched beam and the single edge notched beam tests. In addition, the temperature effect was evaluated by the determination of KIC at different temperatures. Two Superpave mixtures were used for experimental verifications. Results illustrated that there was no significant difference between KIC determined by semi-circular notched beam and single edge notched beam tests within the acceptable statistical margin of error. Finite-element and discrete-element models were created to aid in the verification of the results from the laboratory tests. Further, the evaluation of KIC by semi-circular notched beam at different temperatures showed a similar pattern for all tested mixtures. It was observed that the linear elastic fracture mechanics theory restrictions were not violated when determining KIC for all testing conditions. Overall results suggested that the semi-circular notched beam test can be used for fracture evaluation of hot mixture asphalt, as a screening tool for weak mixtures due to its simplicity and repeatability.