Based on the Burgers model, by adding a damper unit, this paper proposes a new viscoelastic model with five units and eight parameters to characterize the viscoelastic deformation of fiber reinforced asphalt concrete (FRAC). According to the creep tests of FRAC beams, this paper studies both the parameters in the model and the viscoelastic behaviour of FRAC with different fiber volume fraction and aspect ratio. In this model, this paper establishes the viscoelastic constitutive equation of asphalt concrete, which takes into account the impacts of fiber content characteristic parameter. Both the experimental study and theoretical analysis show that the new model has a high correlation with the results of creep experiment and plays a key role in describing the whole creep process of FRAC. The fiber content characteristic parameter can comprehensively reflect the effects of the fiber volume fraction and aspect ratio on the viscoelastic behaviour of FRAC. Within the range of this test, the optimum fiber volume fraction, fiber aspect ratio and fiber content characteristic parameter are 0.35%, 324 and 1.13, respectively.
Taking the AC-13F mixture as the matrix, this paper carries out beam bending tests on fiber asphalt concrete, using the optimal asphalt content (OAC) determined by Marshall test. The test parameters include temperature, fiber volume ratio and fiber aspect ratio. Based on the test results, the author systematically explored how the three parameters affect the flexural performance of asphalt concrete. In addition, the fiber content feature parameter (FCFP) was introduced to describe the combined effect of fiber volume ratio and fiber aspect ratio on the flexural performance of asphalt concrete, and an FCFP-based model was set up to calculate the flexural performance of polyester fiber reinforced concrete beams at different temperatures. The results show that the flexural-tensile strength of fiber asphalt concrete increases first and then decreases with the rising temperature; the failure strain of fiber asphalt concrete increases with temperature; under different temperatures, the flexural-tensile strength of polyester fiber asphalt concrete increases first and then decreases with the growth in fiber volume ratio or fiber aspect ratio; the optimal FCFP of polyester fibers is 1.13. The research findings shed important new light on flexural-tensile performance of polyester fiber asphalt concrete.
This paper aims to accurately measure the fatigue performance and calculate the fatigue life of fiber-reinforced asphalt concrete (FRAC). Firstly, splitting fatigue tests were conducted under the stress control mode. Through the tests, the attenuation features of the FRAC stiffness modulus were analyzed with different fiber contents and length-todiameter ratios. Drawing on damage mechanics theory, a fatigue failure criterion was put forward for the FRAC. Based on stress ratio-fatigue life (S-N) equation, the authors established a calculation model for fatigue life of the FRAC, in the light of the characteristic parameter of fiber content (FCCP). The results show that, the FCCP can reflect the combined effect of fiber content and length-to-diameter ratio on the fatigue performance of the FRAC; With the growth of the FCCP, the FRAC fatigue life always increased first and then decreased; The FRAC realized the longest fatigue life, and achieved the best fatigue performance at the FCCP of 1.13; For AC-13 polyester FRAC (PFAC), the fiber content, length-to-diameter ratio, and the FCCP were optimized as 0.35%, 324, and 1.13, respectively. The research results provide new insights to the fatigue performance of the FRAC.
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