A Study of Relationship Between Residual Asphalt in Aggregate Surface and Aging Degree of its Asphalt

Abstract

Abstract. Laying the road, a lot of asphalt mixing plants use recycled asphalt concrete instead of fresh asphalt concrete. The main reason is that the plants don’t need to provide the viscosity inspection when testing because it is not mentioned in the contract. Even if the value of bitumen viscosity is high in the test report, it is difficult to prove effectively whether to join the asphalt recycled materials or not. This study is to explore the relationship between their extraction of bitumen and coarse aggregate cleanliness by Soxhlet extraction from asphalt recycled materials and fresh asphalt concrete. Besides, we look for the differences after washing asphalt. The research focuses on the method to view the number of the cleanliness on the coarse aggregate surface. The coarse aggregates will be divided into four kinds of sieve (3/4 ", 1/2", 3/8 ", # 4) in process. The selected range is by the built-in program of Photoshop_CS3. We determined the percentage of asphalt area on the aggregates in line with the RGB values. We further used the image processing techniques (Matlab program of image analysis) to assess the relationship of the above mention and compared the basic properties of the asphalt.