AASHTO M 245-20

AASHTO M 245-20 covers polymer-precoated corrugated steel pipe intended for use for storm water drainage, underdrains, the construction of culverts, and similar uses. Pipe covered by this specification is not normally used for the conveyance of sanitary or industrial wastes. The steel sheet used in fabrication of the pipe has a polymer protective coating over a metallic coating of zinc (galvanizing), 55 aluminum-zinc alloy, or zinc-5 percent aluminum-Mischmetal alloy.The polymer coating provides a degree of extra protection for the pipe against abrasion and corrosion as compared to metallic-coated pipe without polymer coating. Some severe environments may cause corrosion problems to accessory items such as rivets or coupling band hardware that does not have a polymer coating. Additional protection for polymer-precoated corrugated steel pipe can be provided by use of coatings applied after fabrication of the pipe as described in M 190.This specification does not include requirements for bedding, backfill, or the relationship between earth cover load and sheet thickness of the pipe. Experience has shown that the successful performance of this product depends upon the proper selection of sheet thickness, type of bedding and backfill, controlled manufacture in the plant, and care in the installation. The installation procedure is described in AASHTO's Standard Specifications for Highway Bridges, Division II, Section 26.