Sometimes science is truly sublime.
Most of Houston’s freeways are now made of concrete, which is more durable than asphalt. But as anyone who has driven on a freeway knows, it’s by no means perfect.
Concrete is, by definition, a porous material. The problem comes when water seeps into concrete and then contracts and expands with changing temperatures. Water also corrodes the reinforcing steel bars inside the concrete.
So you get cracks. Lots of them. And eventually some lucky contractor, typically a large campaign donor, gets a nice fat contract to come in and resurface or even rebuild the freeways.
But what if there were a way to effectively seal off concrete roads and other structures cheaply? A new study from Jordanian researchers suggests there just may be, and the answer lies in a salt & vinegar potato chip ingredient that provides a tangy snap: sodium acetate
Available sealants, such as silicate solutions, are less than ideal. Sodium acetate has more promise, and it’s environmentally friendly. In lab studies using freshly made concrete, the researchers showed that sodium acetate seeps into the concrete, hardens and then crystallizes upon exposure to water. This swelling blocks the entry of additional moisture.
Below is a picture of six concrete cylinders, five of which were treated with solutions of varying concentration with sodium acetate, and then subjected to severe freeze-thaw-freeze conditions. The optimum sodium acetate concentration for the solution was 20 percent:
Industrial & Engineering Chemistry Research
Did I mention that fewer cracks and longer-lasting concrete would translate into fewer road construction delays?