ASTM D2746 Test Method for Staining Tendency of Asphalt (Stain Index)
9. Report
9.1 Report the stain index value determined as in 8.1.
10. Precision and Bias
10.1 Results of two properly conducted tests by a single operator should not differ by more than two stain index numbers for asphalts with stain index of ten or less nor by more than three stain index numbers for asphalts with stain index greater than ten.
10.2 Results of two properly conducted tests on the same sample of asphalt between different laboratories should be considered suspect if they differ by more than four stain index numbers when one of the values is ten or less, or if they differ by more than six stain index numbers when both values are greater than ten.
10.3 A test should be considered suspect if the stain index obtained for the known material differs by more than two from the expected value for materials with stain index of ten or less, or by more than three for materials with stain index greater than 10.
NOTE 6 - The major cause of bias error in this test method has been found to be inadvertent changes in the temperature of the test oven. This is the primary reason for suggesting comparison to a material with known staining tendency in the performance of the test.
11. Keywords
11.1 asphalt; stain index; staining