• Soenen, Hilde
• Porot, Laurent
• Blom, Johan

Abstract

Pavement durability is often linked with water damage either through ravelling or loss of integrity. A large number of tests exists to address experimentally the water sensitivity and affinity between aggregates and asphalt binders. For example, EN 12697-11 combines three standard methods to determine the affinity between aggregates and bituminous binders. This paper focuses on the analysis of bitumen coverage after the rolling bottle test. The aim of this paper is to propose an alternative method to measure the bitumen coverage based on digital image processing techniques. These tests should result in a lower variability between samples, and also ensure a more objective and reproducible test method. In a first part, a number of rolling bottle tests were conducted, using two aggregates and one bitumen. These aggregate-bitumen combinations have been used before in a Rilem round robin test. After these tests, the coverage was measured by a visual inspection as stated in the corresponding norm, and also by a newly developed method, based on digital image processing (DIP). In a second part, photographs obtained from this Rilem SIB TG1 round robin test were used and analysed by DIP. In this part, all the samples from the round robin test were considered, three asphalt binders, two unmodified and a polymer modified binder and four aggregate types with different mineralogy. In the outcome of the round robin test, a large scatter in the absolute results was observed, which could be attributed partly to the visual inspection method. Therefore, digital image processing could provide a better solution in reading the results. In this paper the method is explained and some results obtained from rolling bottle tests are presented. These results look promising, the data show a low variability in the degree of coverage compared to the visual determination.

Topics

• impedance spectroscopy
• polymer
• durability