Experimental evaluation and 3D finite element simulation of creep behaviour of SBS modified asphalt mixture

Abstract

The viscoelastic characteristics of asphalt pavements lead to the occurrence of plastic permanent deformation under repeated traffic loads, a phenomenon referred to as rutting. To address the issue of rutting, asphalt is often modified, with styrene-butadiene-styrene being the most prevalent additive utilized globally. This research involved the preparation of asphalt mixtures incorporating varying proportions of styrene-butadiene-styrene (1 %, 2 %, 3 %, and 4 %), which were then subjected to static creep tests to evaluate their rutting performance. Viscoelastic finite element models were developed based on the experimental creep data, allowing for a comparison between experimental results and simulation outcomes. Following validation, the viscoelastic properties of both control and modified asphalt mixtures were analyzed under various experimental conditions. The findings indicated that the inclusion of styrene-butadiene-styrene markedly enhanced the rutting resistance of the asphalt mixture by mitigating deformations. Furthermore, effective creep models were established using the finite element method, yielding results that closely aligned with the experimental data. Response surface methodology was employed to explore the relationship between varying stress levels and additive ratios, revealing that both factors significantly influence the outcomes, with stress levels exerting a greater impact on the final creep stiffness values than the additive ratio. The analysis also indicated that styrene-butadiene-styrene demonstrates greater efficacy at elevated stress levels, where stiffness values are comparatively low. This study showed that 4 % styrene-butadiene-styrene increased the creep resistance of asphalt mixtures up to 121 %. Moreover, the deformation values obtained by the finite element model agreed with the experimental results with an accuracy of more than 95 %. The response surface analysis revealed that the additive has a significant ameliorative effect on the creep behavior, especially at high stress levels.