Deformation and failure of asphalt-concrete mixtures under dynamic loadsThe project is implemented jointly with "ABZ-1" Company in St. Petersburg and the Research Institute of Mechanics (Lobachevsky State University of Nizhni Novgorod) .
The work is aimed at improving the quality, durability and safety of urban and suburban highways with intensive high-speed traffic. The aim of the project is to assess the effect of speed dependences of ultimate stresses arising in asphalt concrete under the influence of moving transport on operational reliability and safety of road surfaces on highway sections with high speed.
Fig. 1. Strain rate dependences of ultimate failure stresses under compression of samples of various binders for asphalt mixtures at temperatures of 20 and -10 °C.
As a result of the project, new data on dynamic deformation and failure of asphalt concrete mixtures and their components - bituminous binders (BND60/90, PBB60, rubber bitumen) and fillers from rocks were obtained. A сomputational scheme for determining the velocity dependence of the bearing capacity of mixtures and bituminous binders was developed. This scheme can be applied to refine design and predict the life of asphalt concrete pavements.
Fig. 2. Finite-element modeling of stress evolution in asphalt concrete from the moment of contact of a stud with a roadway (a) until fulfillment of the failure criterion (b) and an initiation of failure (c).
Table 1. Estimated critical vehicle speeds for the studied binders and stud mass.
|stud mass||1.6 gram||2.4 gram|
|PBB||95 km/h||74 km/h|
|RBB||71 km/h||56 km/h|
The applied new technology of testing of mixtures and the developed mathematical model open the possibility for optimizing the choice of the composition of asphalt mixtures and their components, taking into account the high-speed modes of transport motion.