LAS VEGAS — Fred Campbell plans to head here early next month with an ambitious goal: to build a flawless 26-foot wall, with 800 bricks, in an hour. That will be enough, he figures, to make him the world champion of bricklaying for a record fourth time and secure his reputation as a masonry superstar.

“It’s going to happen,” said Campbell, a mason from Greeneville, Tenn. “It’s set in stone.”

But a more critical test looms. World of Concrete — the convention that is staging the bricklaying competition — is the first large, in-person trade show scheduled in the United States since the coronavirus pandemic began. The stakes are high, even for a city accustomed to high stakes.