Development of an accelerated pavement test reproducing the effect of natural ageing on skid resistance

This study deals with the development of a new test method simulating the effect of ageing on skid resistance. This test is applied to bituminous mixes in this study, but can also be applied to concrete. This test relies on two machines, the Wehner–Schulze machine, to measure the friction, and the Weatherometer sunset machine, to simulate weather effects (rain, wind, sunlight, etc.). The relevance of this test is evaluated from comparisons between changes in friction and a chemical function linked to bitumen ageing: the carbonyl index. Validation is performed on bituminous mixture samples exposed to natural and accelerated ageing modes. Three very thin asphalt concrete (VTAC) slabs are manufactured in the laboratory with three different types of bitumens. Two specimens are extracted from each slab: one for natural ageing and the other for accelerated ageing. The evolutions of friction and carbonyl index measured on these samples submitted to the two ageing modes exhibit similar tendencies for all three bitumen types, thus confirming the relevance of the test. A conversion factor describing the correspondence between the durations of accelerated ageing and those of natural ageing is proposed for each type of bitumen