Modelling of stress-strain state of asphalt concrete layers in pavements taking into account the results of laboratory four-point bending tests

Abstract

Introduction: Fatigue failure of asphalt concrete pavements is one of the most common causes of premature failure of pavements on operational motorways. Modern laboratory equipment and software tools make it possible to comprehensively consider the problem of fatigue failure both for laboratory deformation modes and for operational ones. The aim of the research: a comprehensive study of fatigue fracture of asphalt concretes used in the upper base layer (UBL), lower pavement layer (LPL), and upper pavement layer (UPL) in operational and laboratory deformation modes. Methods: Laboratory studies are carried out on a four-point bending unit in accordance with the methodology of GOST R 58401.11-19. The analysis of operational modes of deformation is carried out on the mathematical model of the stress-strain state of the layered medium. During the stress-strain state analysis, tensile and compressive radial strains at the lower boundary of each asphalt concrete layer were calculated and compared with the deformation modes modelled under operational conditions. Resistance to fatigue failure of asphalt concretes used for the top layer of base course (A32Ot), bottom layer of pavement (A22Nt), top layer of pavement (SMA-16) was investigated using laboratory equipment for four-point bending tests. Results and discussion:Asphalt concrete stiffness modulus reduction curves depending on the number of applied load cycles were obtained. Using the mathematical model, the operational modes of joint deformation of asphalt concrete layers under the load from the design vehicle are investigated.