This EN 12697-12 method test is conducted on cylindrical specimens prepared in a laboratory (in a gyratory compactor, using a Marshall hammer) or cored from a slab cut out of a pavement. Specimens of 100 ± 3 mm, 150 ± 3 mm, or 160 ± 3 mm in diameter may be tested. When testing specimens 100 mm in diameter (compacted using a Marshall hammer, for instance), only mixtures with a gradation not larger than 0/22 mm can be tested. The set of specimens (minimum of six) of an asphalt mixture is divided into two groups. Both groups should be prepared at approximately the same time (within 1 week or less of each other). Half of the specimens are stored without conditioning, while the other half are subjected to conditioning in water. Specimens are compressed in an indirect tensile test using EN 12697-23. The compression test may be conducted at a selected temperature within a range from 5-25°C.
The standard introduced an index called the indirect tensile strength ratio (ITSR) as a measure of the water resistance of an asphalt mixture, expressed in percent. Apart from the ITSR index, the type of failure, the degree of coating of an aggregate with a binder in a brittle fracture, and the type of aggregate breakage should be given in a test report.
