The New York State Department of Transportation (NYSDOT) is currently using Waterproofing Hot Mix Asphalt (HMA) to overlay their concrete bridge deck systems. The waterproofing characteristics of the mix provide a protective coating on the concrete bridge deck to protect it from future exposure to environmental conditions and de-icing chemicals. However, due to the movements associated with the bridge deck, this thin layer is highly susceptible to fatigue cracking.

In an effort to ensure the NYSDOT is “getting what they are paying for,” the NYSDOT’s Waterproof HMA specification includes performance testing to verify the HMA mixture is indeed fatigue cracking resistant and waterproof. To verify for fatigue cracking, the mixture is evaluated using the Flexural Beam Fatigue test (AASHTO T321). Meanwhile, waterproof verification is done by testing compacted samples in the flexible-wall permeameter (ASTM D5084).