Influence of ageing on viscoelastic properties of PMMA/ATH modified bitumen

This article deals with the influence of the ageing treatment on the viscoelastic behavior of PMMA/ATH modified paving bitumen. Waste composite powder (polymethyl methacrylate filled with aluminium trihydrate)—PMMA/ATH and Fischer–Tropsch wax were used as modifying agents for 70/100 paving grade bitumen. Measurements in intermediate temperature range were carried out under oscillatory shear conditions on a dynamic shear rheometer (DSR). Creep testing in low temperature range was conducted on a bending beam rheometer (BBR). The time‐dependent behavior of investigated samples was presented in a form of relaxation moduli G(t) and E(t). Dynamic moduli, i.e., G′(ω) and G″(ω), were converted to relaxation modulus G(t) using the Schwarzl method. The interconversion between tensile creep compliance D(t), and tensile relaxation modulus E(t) was performed using the Hopkins and Hamming approach. It was found that modified binders are less susceptible to the oxidation process during bitumen ageing, since the viscoelastic properties changed less than for the base bitumen. Our results indicate that the use of waste PMMA/ATH in the selected bitumen altered the time‐dependent deformation behavior of asphalt binder. The effect of ageing treatment on material functions was particularly manifested at longer times. Different stress relaxation behavior of modified binders could result in higher deformation resistance of asphalt mixture. POLYM. COMPOS., 36:1738–1747, 2015. © 2014 Society of Plastics Engineers