Over 90% of Australia's surfaced roads are unbound pavements with sprayed seals. However, achieving complete impermeability with these seals is challenging, leading to some moisture exchange between pavement layers and the environment. As moisture fluctuations influenced by climatic factors significantly affect the structural performance of particularly unbound granular layers, there is a pressing need to enhance Australian pavement design by incorporating climatic effects to meet better pavement performance. Hence, the current study numerically evaluates the degree of moisture saturation (\({S}_{r})\) variations of pavement layers under different Australian climates. This paper reveals how ambient climate impacts the moisture variations of pavement layers based on the results of 126 numerical simulations performed. Results indicated that the annual rainfall is not an appropriate parameter to decide the service moisture condition of the UGM layer, but the ratio between annual rainfall and annual pan evaporation (\(\frac{P}{{\text{PE}}}\)) combined with the saturated permeability of the seal (\({K}_{{\text{s}}})\) is found to be a better indicator. More importantly, this study develops a novel empirical model to predict the service moisture condition of the UGM layers aiming to advance the current Australian pavement design guide. Furthermore, a correlation between pavement moisture and a widely used climatic index, Thornthwaite Moisture Index (\({\text{TMI}}\)) is presented in this study. Furthermore, this paper proposes a novel approach to integrating climatic factors into the current Australian pavement design of unbound pavements with thin seals. This study enhances understanding of the complex relationship between climate and pavement moisture by taking a multi-dimensional approach.

澳大利亚 90% 以上的路面都是喷洒密封层的无粘结路面。然而，用这些密封件实现完全的不渗透性具有挑战性，导致路面层和环境之间发生一些水分交换。由于受气候因素影响的湿度波动会显着影响特别是未粘合颗粒层的结构性能，因此迫切需要通过纳入气候影响来增强澳大利亚路面设计，以满足更好的路面性能。因此，当前的研究数值评估了澳大利亚不同气候下路面层的湿度饱和度（\({S}_{r})\）变化。本文基于 126 次数值模拟的结果揭示了环境气候如何影响路面层的湿度变化。结果表明，年降雨量并不是决定UGM层使用水分条件的合适参数，而是年降雨量与年蒸发皿蒸发量的比值（\(\frac{P}{{\text{PE}}}\ ) ) 与密封件的饱和渗透率 ( \({K}_{{\text{s}}})\)相结合是一个更好的指标。更重要的是，本研究开发了一种新颖的经验模型来预测 UGM 层的使用湿度条件，旨在推进当前的澳大利亚路面设计指南。此外，本研究还提出了路面湿度与广泛使用的气候指数 Thornthwaite 湿度指数 ( \({\text{TMI}}\) )之间的相关性。此外，本文提出了一种新颖的方法，将气候因素纳入澳大利亚当前薄密封非粘合路面的路面设计中。这项研究通过采用多维方法增强了对气候与路面湿度之间复杂关系的理解。