ABSTRACT

Prediction of solvent diffusion and evaporation rate in the initial days after construction of a sprayed seal is of special concern for pavement performance assessment. It is still a major challenge as solvent evaporation is a very complicated process. In this study, laboratory tests were conducted on bitumen-solvent binder films, under different experimental conditions and varying solvent properties. A solution of Fick’s diffusion equation was then used to calculate solvent diffusion coefficient (D) values for the initial 7 days. While a strong correlation was found between D and solvent viscosity as well as D and solvent distillation range, no relationship was found between D and solvent aniline point nor aromatic content. These findings were utilised in developing a multiple linear regression (MLR) diffusion model for the initial 7 days of evaporation. The evaluation of the model indicated close agreement between the predictions and experimental values (R²= 0.95). The model enables road agencies to predict solvent diffusion and residual solvent for the early life of a sprayed seal without needing to conduct extensive experiments thereby saving time and labour cost. Accurate prediction of residual solvent via the developed model will further ensure long-term performance of sprayed seals.

摘要

喷涂密封施工后最初几天的溶剂扩散和蒸发速率的预测是路面性能评估特别关注的问题。这仍然是一个重大挑战，因为溶剂蒸发是一个非常复杂的过程。在这项研究中，在不同的实验条件和不同的溶剂特性下，对沥青溶剂粘合剂薄膜进行了实验室测试。然后使用 Fick 扩散方程的解来计算最初 7 天的溶剂扩散系数 (D) 值。虽然在 D 和溶剂粘度以及 D 和溶剂蒸馏范围之间发现了强相关性，但在 D 和溶剂苯胺点或芳烃含量之间没有发现关系。这些发现被用于开发最初 7 天蒸发的多元线性回归 (MLR) 扩散模型。模型的评估表明预测值和实验值非常吻合（R ² = 0.95)。该模型使道路机构能够预测喷涂密封件早期寿命的溶剂扩散和残留溶剂，而无需进行大量实验，从而节省时间和劳动力成本。通过开发的模型准确预测残留溶剂将进一步确保喷涂密封件的长期性能。