부산대학교 도서관

SM-4.75 asphalt mixtures incorporate a 4.75-mm nominal maximum aggregate size along with a corresponding fine gradation that accommodates higher liquid asphalt contents, which promotes durability. The SM-4.75 materials are suited to take advantage of the lower cost finer fractions of the stone-crushing process. The fine gradation also permits very thin applications (19 mm to 25 mm), thereby reducing the quantity and cost of materials, as well as construction time. Mixtures with 4.75-mm nominal maximum aggregate size have the potential to improve riding quality, extend pavement life, increase durability, and reduce permeability and road-tire noise. This study evaluated the laboratory cracking performance of SM-4.75 mixtures. It was done through sampling and testing of plant-produced mixtures that were placed on low volume traffic routes. Several tests were used to characterize the mixtures including the simplified viscoelastic continuum damage test, indirect tensile asphalt cracking tests, the semi-circular bend test, and the overlay test. Laboratory cracking tests indicated that SM-4.75 mixtures are crack susceptible and would benefit from higher binder contents. However, field performance data for the tested mixtures are needed to validate the crack susceptibility of the mixtures. In general, laboratory performance ranking order among different tests is not consistent for different mixtures. Binder testing results indicated that the majority of the mixtures should be resistant to non-load related cracking, even though the mixtures contained 20% and 30% recycled asphalt pavement. [ABSTRACT FROM AUTHOR]