AASHTO is the American Association of State Highway and Transportation Officials. This organization sets standards for highway design and construction.
As it relates to bolts, often times, bolts and other materials will be shown on plans for state transportation projects as having an AASHTO designation. These AASHTO numbers typically will correlate directly to a particular ASTM specification, with the verbiage actually coming directly from the associated ASTM designation.
AASHTO to ASTM Conversion Table
| AASHTO Grade | ASTM Equivalent | Description |
|---|---|---|
| M-111 | A123 | Hot-dip galvanizing of iron and steel products |
| M-164 | A325 | Structural bolt |
| M-183 | A36 | Raw material, low carbon steel |
| M-222 | A588 | Raw material, weathering steel |
| M-223 | A572 | Raw material, high strength low alloy |
| M-232 | A153 | Hot-dip galvanizing of fasteners |
| M-253 | A490 | Structural bolt |
| M-291 | A563 | Nut specification possessing many grades |
| M-292 | A194 | High strength, heavy hex nut |
| M-293 | F436 | Hardened washer |
| M-314 | F1554 | Anchor bolt specification with 3 grades |