Moisture characteristics of mixtures with warm mix asphalt technologies - A review

- Warm mix asphalt has been widely used as an environmentally friendly technology.
- Moisture damage is considered as one of the main concerns for WMA mixtures.
- The commonly used test methods are tensile strength ratio (TSR) test.
- Materials, aggregate and asphalt played important roles in moisture characteristics.
- Compacting temperature and warm mix technologies influence the moisture behavior.

Warm mix asphalt (WMA) has been widely used as an environmentally friendly technology. Due to the lower temperature than hot mix asphalt (HMA) and some influences of warm mix technologies, moisture damage is considered as one of the main concerns for WMA mixtures. This review focuses on the influences of various factors on the moisture susceptibility of WMA mixtures. The commonly used test methods are briefly introduced, while tensile strength ratio (TSR) test is the most commonly used method to evaluate the moisture susceptibility. Then the influence of materials and technologies are illustrated. Materials, aggregate and asphalt, play important roles in the moisture characteristics of mixtures. Compacting temperature and other warm mix technologies also significantly influence the moisture characteristics. The purpose of this review is to provide assistance to the project engineer when WMA technologies are employed.