Incompatibility between aggregate type and asphalt binder, presence of standing water or water under pressure in the pavement layers, and improper construction practices are some of the many factors that influence moisture susceptibility of flexible pavements.
The TRB National Cooperative Highway Research Program's NCHRP Synthesis 595: Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements documents practices used by state departments of transportation to prevent or to minimize moisture damage in hot-mix asphalt pavements.