Abstract
The rheological behaviour of asphalt concrete is mostly stipulated by the time-temperature (frequency) peculiarities of the mechanical behaviour of bitumen binder. Bitumen is among the first item of research in rheological science. One criteria of the objective evaluation of the rheological properties of bitumen is realised in the condition of its deformation in the linearity region.
In relation to asphalt concrete, this criterion allows the applicability of the method of time-temperature superposition according Williams-Landel-Ferry model for complex moduli and their dependence on the composition of asphalt concrete and type of bitumen (sol, gel, or sol-gel) to be proven. Also, it can show the direct relation between complex moduli of asphalt concrete and the complex shear modulus of bitumen binder, providing a method of calculation of the complex modulus of asphalt concrete with the complex shear modulus of bitumen. However, it is not clear on which parameters of bitumen and bituminous binder properties the asphalt concrete linear viscoelastic LVE behaviour depends directly.
This paper aims to illustrate that this parameter is the maximal shear stress in bitumen binder, which is obtained with the same asphalt concrete temperatures and frequencies or equal deformation rates. Considering this, maximal shear stress can be obtained with monoplanar or rotational shear, as with the calculation method.
This research uses a monoplanar cohesion meter, a rotational viscometer, and test equipment to determine the complex moduli of asphalt concrete by means of harmonic oscillation, corresponding to EN 12697-26:2012.
Keywords
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