In the 1990s, asphalt durability problems due to the use of new deicing chemicals were observed at some Nordic airports. Degradation and disintegration of asphalt pavements occurred and there were also softening and stripping effects on bitumen and asphalt concrete together with loose stones onthe runways. The problems occurred when many airports in Norway and Sweden changed from urea to potassium acetate and potassium formate. Requirements from environmental authorities come because of nitrogen problems and over-fertilisation of soil and watercourses around airports caused by urea. For this reason, a method for determining adhesion of asphalt concrete after storage in deicing agent was developed. This method is named LFV Method2-98 (see enclosure). The storage time in the method is 70 days at a temperature of 40degreesC. Comparison with adhesion value of specimen not stored in deicing agent is then done. The project to develop LFV Method 2-98 carried out by Norwegian and Swedish Civil Aviation Administrations (CAA). Later on, the Finnish Civil Aviation Administration joined the project. Toget a resistant asphalt pavement as possible on runways LFV Method 2-98 is used as a technical criteria in connection with purchasing of runway andaircraft deicers, asphalt pavements and bitumen. Swedish CAA has general agreements for runway and aircraft deicers together with bitumen. In connection with purchasing of asphalt pavement and bitumen the actual deicers at the airports are used in the tests. The CAA in Norway, Sweden and Finland use the same technical requirement specification including LFV Method 2-98 in purchasing runway deicers. The major airports in Denmark are also interested in using the same technical requirement specification. LFV Method2-98 is also a European standard method within CEN (European Committee for standardization) named EN 12697-43. Likewise there is standardization work going on in the SAE G-12 Fluids Subcommittee to get LFV Method 2-98 as standard method within the international requirement specifications for deicers. The aim is to introduce requirements of the runway deicing agent effect on asphalt and bitumen in the SAE AMS specifications 1431 and 1435. In the long run it is also planned to introduce the same requirements for aircraft deicing agents in SAE AMS 1424 and 1428. A round robin test has been carried through to have the repeatability (within a laboratory) and thereproducibility (between participating laboratories) of the method well defined. The precision data are according to ISO 5725. For the covering abstract see ITRD E139491.
Abstract