Evaluation of Hydrated Lime Effect on the Performance of Rubber-Modified HMA Mixtures

The main objective of this research was to evaluate the effect of hydrated lime on the performance of rubber-modified hot mix asphalt (HMA) mixtures. The hydrated lime was incorporated into the mixtures using three different methods, namely, the dry method, the wet method, and the slurry method. The performance of the studied mixtures was evaluated based on their indirect tensile strength, resilient modulus, fracture resistance, fatigue life, and creep compliance. The fracture resistance and fatigue life of the studied mixtures were determined using the semi-circular bend test and the split tension controlled-stress fatigue test, respectively. A power law model was used to characterize the creep compliance behavior of the studied mixtures. Crumb rubber content of 15% by weight of the binder and hydrated lime content of 3% by weight of the total mix were incorporated for all the tested specimens. Testing temperature was kept constant at 35°C. The results indicated that the application of hydrated lime has enhanced the indirect tensile strength, stiffness, fatigue endurance, fracture resistance, and the permanent deformation characteristics of the rubber-modified HMA mixtures. Mixtures contain hydrated lime added using the wet method experienced the highest indirect tensile strength, resilient modulus, fracture resistance, and lowest creep compliance. Fatigue life of the tested mixtures has demonstrated less dependency on the hydrated lime application method.