Why would you add hydrated lime to an asphalt mix?

Adding hydrated lime to an asphalt mix is primarily done to reduce moisture damage occurrence. This is important in asphalt pavement, where moisture can lead to stripping of the asphalt binder from the aggregates, ultimately compromising the integrity and lifespan of the pavement. Hydrated lime acts as a moisture scavenger, effectively improving the adhesion between the asphalt and the aggregates. This enhanced bonding reduces the potential for damage due to water infiltration, making the asphalt more durable under various environmental conditions.

While enhancing color, increasing flexibility, or decreasing density are potential factors to consider in asphalt mixes, they do not represent the primary benefit of using hydrated lime. The focus on moisture damage is critical in ensuring long-term performance and stability of asphalt pavements, which is why the addition of hydrated lime is a common practice in the industry.