Friction on road surfaces contaminated by fine particles: Some new experimental evidences

Abstract

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Observations of dry particles behaviour at the tyre/road interface

“…During friction tests, carbon adhesive discs were placed 50 mm away from the slab to capture particles ejected from it at passages 1,2,3,5 and 12. In accordance with Y. Hichri et al [13], the passages 1,2 and 3 correspond with the fastest variation of the friction. Passage 5 corresponds with the slow increase of the friction and it is the passage at the half of the test.…”

“…The same testing procedure as the one of Y. Hichri et al [14] was followed. Friction was measured on a clean and dry aluminium slab, as indeed Y. Hichri et al [13] showed, roughness parameters of the aluminium slab are similar to road aggregates polished by the traffic. The friction was measured after the deposit of particles, then the measurement of friction was repeated until stabilisation of the friction coefficient.…”

“…Lastly, Y. Hichri et al [13,14] demonstrated that the finest fraction (i.e.0-40 μm induces a lower friction value after one measure with particles (step 1), then the increase of the friction value with the number of steps is the slowest. Friction values measured with the fraction 80-100 μm increase rapidly after step 1.…”

“…As explained in the introduction, several authors have shown that friction values depend on the size of particles. More specifically Y. Hichri et al [13,14] noticed that the presence of particles smaller than 40 μm has a huge and lasting influence on friction. They measured a lower friction coefficient for the first passage with the fraction 80-100 μm than with the fraction 0-40 μm.…”

“…Nevertheless, Mills et al [12] and more recently Y. Hichri et al [13,14] have observed that friction is already reduced on dry contaminated roads. These authors measured the friction by means of a Skid Resistance Tester (SRT) Pendulum which is widely used on roads field as a reference.…”