Moisture susceptibility of hydrated lime modified mastics using adhesion test methods and surface free energy techniques

Moisture damage is one of the major factors that has been reported to affect the performance of asphalt pavements which depends mainly on the bond strength between bitumen, aggregates and mineral filler. In the presence of moisture, this bond weakens and results in premature pavement failure. One of the many ways of mitigating moisture damage effects is the use of anti-stripping agents. 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 (granite and limestone) under moisture conditions using a combination of surface free energy techniques and conventional adhesion test methods. From the surface free energy 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 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 mineralogy.

Automated summary

The study confirms that hydrated lime is an effective anti-stripping agent that improves moisture damage resistance of pavements, but its effectiveness is highly dependent on aggregate mineralogy.