Three-point bending test on prismatic-shaped specimens

Three-point bending test on prismatic-shaped specimens 

This test method determines the behaviour of the asphalts under repetitive fatigue loading with controlled displacement by three-point bending, using prismatic beam-shaped specimens of equal width and height. The test can be used for asphalts with maximum aggregate size D up to 22 mm. 

The prismatic beam-shaped specimens are obtained from samples manufactured in the laboratory using a roller compactor according to CEN EN 12697-33 (2007) or from samples cored from road layers with thickness 50 mm. In any case, the specimens are cut in the desired dimensions, 50 mm x 50 mm x 300 mm, and are tested after ageing (stored at 20 C for 14 to 42 days). 

At least 10 element tests are required in order to characterise the asphalt s behaviour through the determination of the fatigue law in terms of strain (relation between strain and number of load cycles at failure) and the associated energy law. Element tests are tests carried out at different displacement amplitudes. 

The prismatic beam is clamped in both edges and a constant amplitude sinusoidal displacement is applied to the mid-span point of the beam by a piston rod, with a wave frequency of 10 Hz. 

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