From the New York Times today by Danielle Ivory and Julie Creswell - Trump Sees a Wall, Contractors See Windfalls:
"An infrastructure build-out could also increase the cost of cement and other materials, say analysts. Currently, the United States is operating at 90 percent of its capacity levels, estimates Garik Shmois, an analyst at Longbow Research of Independence, Ohio. "We're going to be effectively sold out by 2018 based on current projects," Mr. Shmois said. "So any additional period of growth, such as an infrastructure cycle, will put upward pressure on prices.