Environmentally friendly pavement design integrating multilayer thermo-viscoelasticity into an optimization framework for balancing global warming indicator and economic costs

This study presents an advanced Multi-Objective Optimization (MOO) framework for flexible pavement design that integrates multilayer thermo-viscoelastic material behavior. The framework automatically optimizes key pavement layer properties, specifically the material type, layer thickness, and number of layers, with respect to two conflicting and weighted objectives: economic costs and Global Warming Indicator (GWI). Pavement performance is assessed during the optimization process, considering the temperature- and time-dependent behavior of the materials. The developed framework is applied to five scenarios, four of them being synthetic, differentiating themselves by their climatic conditions, and the fifth representing a real-life project. Results demonstrate a strong influence of temperature on optimal pavement layer properties, with maximum differences in total thickness of up to 0.39 m and service life deviations of up to 7.48 years depending on climatic assumptions. Compared to a conventional pavement layer configuration chosen manually by a pavement designer, the MOO framework achieved reductions of up to 18.45 % in costs and up to 11.09 % in GWI, depending on the weight values used to aggregate the objective functions. These findings highlight the importance of accounting for thermo-viscoelastic effects in the simultaneous optimization of both GWI and costs.