Introduction. Fatigue strength is the most important criterion for the asphalt concrete quality evaluation, namely its ability to resist the destructive action of vehicles. The number of cycles that can withstand asphalt concrete during bending with constant amplitudes of load or deformation to failure is used as such a criterion.
The issue statement. Under current conditions of increasing traffic volume, in order to obtain reliable results of fatigue life evaluation of asphalt concrete pavements, it is necessary to switch to new methods of testing the asphalt concrete during repeated impact of vehicle loads. Until recently, the existing regulatory framework allowed testing asphalt pavements only under a single static load, which made it impossible to assess their resistance to long-term repeated cyclic loads. In the absence of well-founded and documented testing methods, it was impossible to determine the regularities of fatigue failure which is often established under visual inspection of roads in Ukraine. Upon entry into force of DSTU EN 12697‑24: 2018 (EN 12697-24: 2012, IDT) "Bituminous mixtures. Test methods for hot mix asphalt. Part 24. Resistance to fatigue." It is become possible to carry out such assessment and obtaining the information about the operating modes of the load of asphalt concrete in the road pavement the result of which is to determine a pattern of material fatigue life changes depending on the characteristics of the load and temperature impacts. Thus, it will make possibility to carry out asphalt concrete mix design taking into account the predicted number of load cycles, thereby determining the ways to improve the fatigue life of asphalt concrete pavements and ensure their reliable operation in road structures during the design service life.
Purpose. Experimental study of the fatigue life of asphalt concrete the result of which is to determine a pattern of material fatigue life changes depending on the characteristics of the load and temperature impacts and development of the ways to improve it based on the results obtained.
Materials and methods. For the experimental study samples-beams from hot asphalt concrete mixtures of different types were produced and tested for four-point bending.
The results. The analysis of information sources on the existing experience of multiple cyclic loading test was carried out. The device for determination of fatigue resistance of asphalt concrete on four-point bending was developed. Samples-beams from different types of asphalt concrete were tested and regularities of fatigue life changes were established.
Conclusions. Impact of load frequency on fracture processes is experimentally confirmed. The results obtained make it possible to establish the predicted service life and estimate the residual life of the road structure.
