In this investigation samples of steel plate surfaced with mastic asphalt were subjected to repeated dynamic loading, in 3 point bending, until fatigue cracking occurred. The force/time variation was chosen to simulate the effects of real traffic. Single load applications were used to assess the stiffness of the samples. All tests were conducted at controlled temperatures. The principal results were that: (i) Fatigue cracking initiates in the mortar and is unaffected by variations in coarse aggregate content between 30% and 50%; (ii) The stiffness of composite steel/ashpalt plates is very sensitive to the thickness of the adhesive layer; (iii) Increasing the pause between successive cycles was found to improve the fatigue life by a factor of up to 4 or 5; (iv) Fatigue performance under variable amplitude loading is satisfactorily predictable using the Palmgren-Miner rule.

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