Which laboratory test is used to assess the moisture sensitivity of asphalt mixes?

The Tensile Strength Ratio test is the correct choice because it specifically evaluates the moisture sensitivity of asphalt mixes. This test measures the strength of an asphalt mixture when conditioned in the presence of moisture compared to its strength when dry. By assessing the tensile strength before and after moisture exposure, this test helps determine how well the asphalt mixture can resist stripping or weakening due to water infiltrating the mix.

This aspect of moisture sensitivity is critical for ensuring the durability and longevity of asphalt pavements, especially in climates where moisture intrusion is a concern. A high tensile strength ratio indicates good moisture resistance, while a low ratio suggests that the mix is prone to failure when exposed to moisture.

In contrast, the other laboratory tests mentioned serve different purposes. For instance, the Marshall Stability Test evaluates the load-bearing capacity of asphalt mixtures, while the Dynamic Modulus Test assesses the elastic properties and performance under various temperatures and loading conditions. The Superpave Gyratory Compactor test is primarily used for determining the compaction characteristics of asphalt mixtures but does not directly relate to moisture sensitivity. Thus, these tests do not focus on the specifics of moisture-related performance like the Tensile Strength Ratio test does.