Katie does highways
Last night's CBS-TV Evening News featured a powerful story about the deteriorating state of US highways and the simple solution of injecting new funding into their repair and maintenance. Anchor Katie Couric's part one of "The Road Ahead" series was helpful, but for one error that prompted me to comment:
Good article with one significant error. The careless attribution of a pothole to "salt damage" is unfounded.Salt has often been blamed for causing potholes. Potholes are caused by water entering the grade below the surface of the road and then freezing. This freezing cause the road surface to heave. Thawing leaves a cavity or weakened spot beneath the surface. Traffic then causes the surface to collapse into the cavity creating a pothole. Salt can cause surface spalling of poor concrete or scaling of non-air-entrained concrete. It has no bad effects on asphalt or the air-entrained concrete that is available today for road building.
For more see http://www.saltinstitute.org/30.html or "Deicing Salt Facts" at http://www.saltinstitute.org/34.html.
Even in its diminished current condition, once-proud CBS-TV still has the potential to misinform millions.
