I am writing in support of Derek Green's letter regarding pothole repairs ("Pothole Prevention," Feb. 19). As an engineer and former municipal manager, I can tell you from experience that it is possible to make long-lasting pothole repairs as set forth below.
The main culprit in the formation of potholes is water. Water enters the pavement through cracks, freezes, expands and, voila, a pothole is created. Every spring television newscasts show workers shoveling asphalt "cold patch" into potholes filled with standing water. Guess what happens the next time temperatures dip below freezing? The water at the bottom of the new asphalt freezes, expands and pops the newly placed asphalt, thereby recreating the pothole. There is a better, albeit more time-consuming, way to repair potholes:
1. Start by using a saw or pneumatic spade to square the edges of the pothole to form a rectangle. It also is very important that the sides of the pothole be made vertical to lessen the chances that the new asphalt will "slide" out when a tire rolls over it.
2. Remove all loose material from the pothole.
3. Use a propane torch to dry any water in the hole and to soften the remaining asphalt so that it will bond with the cold patch.
4. Place the cold patch in the hole and compact with a pneumatic compactor or roller, not by simply rolling it with a truck tire.
5. Seal the perimeter of the cold patch.
Cold patch is a material that is used in the winter when hot asphalt is unavailable. Usually it is considered a temporary repair until the asphalt plants open in the spring and the cold patch can be removed and replaced with hot asphalt. However, properly installed cold patch can last as long as hot asphalt, thereby offsetting the added time that it takes to install it and minimizing the inconvenience to the public.
WILLIAM B. GORDON