63.51.3mm. According to Marshall test, measure the diameter and height of the specimen with vernier caliper. If the height of the specimen does not meet the requirement of 63.5 1.3 mm or the height difference between the two sides is greater than 2mm, the specimen is invalid, so the Marshall specimen height is 63.5 1.3 mm, and Marshall test is a test to determine the best asphalt-aggregate ratio of asphalt mixture.