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Moisture damage is one of the major factors that has been reported to affect the performance of asphalt pavements with asphalt mixture performance depending mainly on the bond strength between bitumen, aggregate and mineral filler. In the presence of moisture, this bond weakens and results in premature pavement failure due to cohesion or adhesion loss. One of the many ways of mitigating moisture damage effects is the use of anti-stripping agents like liquid polymers, Portland cement, hydrated lime, fly ash, flue dust, etc. Hydrated lime has been found to be one of the most efficient anti-stripping agents among the common additives used with asphalt mixtures. This study attempts to quantify the bond strength of hydrated lime modified mastics with different aggregates under moisture conditions using a combination of surface free energy techniques and conventional adhesion test methods. From the surface free energy (SFE) technique, the moisture susceptibility was studied in the form of dry work of adhesion, work of debonding and various energy parameters. Two conventional techniques, the PATTI test and the rolling bottle test were used to assess bond strength under wet conditions. The results of all three techniques lead to the same conclusion that there was a positive effect of HL addition observed in case of granite aggregates with the best performance being found in the mastic having 20% HL (equivalent to 2% HL in the total asphalt mixture). On the other hand, the mastic containing HL when used with limestone aggregates did not show any improvement of the adhesion properties under moisture conditions. It can be concluded that hydrated lime is an active filler that improves moisture damage resistance compared to the other natural fillers but that the improvement is highly dependent on aggregate minerology.

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