Comparative laboratory evaluation of macro texture depth of surface coatings with standard volumetric test methods

- Relative differences in MTDs of surface coatings for SP and OFM tests were determined as 21% in average.
- Each test method is able to specify the MTDs with increasing aggregate sizes.
- 6 mm MTD can be identified as a threshold for implementation of outflow meter test.

In this research, macro texture depth of surface coatings including chip seals and slurry seals were evaluated with two volumetric test methods. Chip seals and slurry seals, one hundred in total, were manufactured with different aggregate types and grading sizes. Mean texture depths (MTDs) of each sample were computed via sand patch and outflow meter tests according to ASTM E 965-12 and ASTM E 2380-12, respectively. Applicability of both test methods was examined and relative differences in MTDs for chip seal and slurry seal samples were determined as 21% in average. As a result, each test method is able to specify the MTDs with increasing aggregate sizes; whereas 6 mm MTD can be identified as a threshold for implementation of outflow meter test.