Why the paint is peeling off the Lincoln Memorial Reflecting Pool--experts explain
The Lincoln Memorial Reflecting Pool's makeover was supposed to inspire patriotism, but chunks of material peeling off the pool's surface have instead garnered more puzzlement and speculation.
-snip-
When applying coats of polyurea, workers need to make sure they paint on a new coat within 24 hours, or less, of the last layer, depending on the specific type of the substance being used. That ensures the polyurea layers adhere to one another and form a solid mass, blocking water from seeping through. And different methods of application can result in stronger or weaker molecular bonds. Given the renovation's short timeline—around eight weeks—it's possible the material wasn't applied adequately to prevent damage. The bottom of the pool may also have been affected by the presence of heavy equipment and trucks—and a presidential motorcade that drove through at one point—while the coating was being prepared and applied.
The decision to use polyurea in the first place will also require investigation, Auerhahn notes. "The material that you're adhering that polyurea coating to is questionable," he says. "They were adhering it to granite."
The precise material in question, Rhino Linings' Pipeliner 5000, can bond to "virtually all substrates," according to the company's commercial data sheet, but granite is not specifically listed. Rhino Linings was not the contractor that applied the coating to the Reflecting Pool. The company did not immediately respond to a request for comment.
https://www.yahoo.com/news/science/articles/why-paint-peeling-off-lincoln-193000369.html
= new reply since forum marked as read
