There may be sites where the three coatings available (galvanized, ALT2 and polymer) on steel delivered to pipe fabrication facilities may not be the best match for the site conditions. Additional add-on service life can be provided by coating or paving the invert of CSP with asphalt either after fabrication or after installation.
Types of asphalt coated pipe:
| Service Life Ad-ons for Supplemental Paving and Coatings |
| Coatings Material |
FHWA Abrasion Level |
| 1 |
2 |
3 |
4 |
| Add-on Service Life (Years) |
| Asphalt Coated |
10 |
10 |
N/R |
N/R |
| Asphalt Coated and Paved |
30 |
30 |
20 |
N/R |
| NOTE: N/R = Not Recommended |
|