Some of the earliest uses of Asphalt-Rubber chip seals and Hot Mix Asphalt-Rubber occurred on airport runways across the U. S. By 1984 over half of the states had A-R on a municipal airport or a military airfield runway. Over 150 projects had proven it to be flexible and durable. One of the pioneer runways was Sky Harbor International Airport in Phoenix. The first A-R test section was placed in 1964. By l973, six test sections had been placed and were performing so well that city engineers decided to rehabilitate the entire runway with an A-R seal coat. The result is seen above in a view of the main runway on April 12, 1973. In 1977, comparative viscosity of asphalt extractions from the airport mixes showed that the mixes without an A-R seal had an average viscosity of 18,430 poises at 140 F while the mixes with an A-R seal coat had an average viscosity of 1,980 poises at 140 F. This confirmed that A-R seals provided better protection against hardening and oxidation of the asphalt in the underlying bituminous mix. Charles McDonald, A-R inventor, detailed the findings in a letter to Doug Bemard at the Federal Highway Administration. A recent example of an airport A-R hot mix application can be seen at the Oakland, California airport. Granite Construction placed an open-graded friction course there in 1999. Mark Chalfa was the A-R project engineer. Lord joins TAB Byron Lord, senior pavement technology engineer, Office of Pavement Technology, Federal Highway Administration, has joined RPA's Technical Advisory Board. Lord, a graduate Civil Engineer with a Bachelor's Degree from the Citadel and a Master's Degree from West Virginia University, directs FHWA's pavement technology programs. He is a member of the advisory boards of the Pennsylvania Transportation Institute and the National Highway and Transportation Management Institute. He is also on the Board of Directors of the National Center for Asphalt Technology and the Steering Committee for the National Quality Initiative. Lord served as a National Science and Technology Fellow from 1988 to 1989 assigned to the Executive Office of the President. Home | Contents & Calendar | Page 2 | Page 3 | Page 4 | Page 5 | Page 6 | Page 7 | Page 8 | Contacts and Credits