AASHTO M 178M/M 178-20

AASHTO M 178M/M 178-20 covers concrete drain tile with internal diameters from 100 mm (4 in.) to 900 mm (36 in.) that is intended to be used for surface and subsurface drainage.This specification is a manufacturing and purchase specification only and does not include requirements for bedding, backfill or the relationship between field load condition and the strength classification of drain tile.This specification agrees with ASTM c 412M-05a and C 412-05a except that the absorption test is limited to the 5-h boil method and the manufacturer is not afforded the option to supply inch-pound sized pipe when the order is placed in SI units.