PREDICTION OF RUTTING FORMATION IN ASPHALT CONCRETE PAVEMENT

Asphalt pavement in actual circumstances is subjected to the repetitive and changing transport load. As a result of the repetitive load impact, both elastic and plastic deformations occur to the pavement. Accumulation of plastic deformations in one or several layers leads to appearance of permanent deformations or rutting. This type of deformations reduces safety and convenience of traffic. Aim of the research is investigation of the rutting dynamics on the dense graded asphalt concrete (AC) and stone mastic asphalt (SMA) mixtures. The research has been made by using the standard performance test method - wheel tracking test (WTT). Five compositions of the dense graded AC mixture and two compositions of the SMA with the conventional aggregate and one reference mixture AC 11 with the Martin steel slag aggregate have been used in the experiment. The B70/100 unmodified bitumen and SBS modified ModBit 80B has been used for the investigated mixtures. The results have shown poor strain stability of the conventional mixtures with unmodified bitumen under the heavy transport load, in comparison with the reference mixture AC 11 and SMA with modified bitumen. The results of investigating the rutting dynamics under the intensive heavy transport load have shown that the allowed rut depth 25 mm is reached already during the first year of the asphalt pavement exploitation.