Many Iowans enjoy a foamy cup of hot black gourmet coffee while traveling down the highway. Iowa’s Department of Transportation is testing a foamy black mixture of another sort to make sure they don’t spill their java. The D-O-T’s testing a new mixture of water and hot asphalt that’s called “foamed asphalt”. Mike Heitzman of the D-O-T’s materials lab says foamed asphalt was invented in the 1950’s, but is just now becoming practical.The D-O-T will demonstrate the new material next week. Heitzman says foamed asphalt doesn’t have the temperature restrictions of the traditional paving mixture — thereby extending the construction season. It also provides a quick way to recycle old asphalt. The old asphalt is ground up into the new mixture.Heitzman says the foamed asphalt could really help contractors make repairs and build new roads.Heitzman doesn’t know if there will be any cost advantages to the new foamed asphalt as it depends on how often the process is used.