RESEARCH ON LOW-TEMPERATURE FRACTURING OF ASPHALT PAVEMENT

Various failures occur in asphalt pavements, and researches on these f ailures were carried out. Most of them were on rutting or fracturing p henomenon, but research on low temperature fracturing, which is very i mportant in cold regions, have been insufficient, as of now. This is m ainly due to the fact that circumstances make it extremely difficult t o research, including factors, such as material properties, constructi on conditions, particular kind of structure involved in asphalt paveme nt, and the prevailing environment. Recently, the authors investigated the relation between low temperature cracking in asphalt pavement in cold regions, such as Hokkaido, and pavement structure with varying pr operties of asphalt mixture. These researches were carried out in cons truction fields, and the laboratory, performing simulation analysis of finite element method using visco-elastic program of hybrid type. The authors arrived at the following conclusions in this study: the low t emperature fractures in asphalt pavements in cold region depends mainl y upon the strain, more so than on the stress, in asphaltic mixture. T he low temperature fracture may occur when strain in the asphalt pavem ent reaches a critical value accompanying relaxation of stress in asph altic mixture.