Thursday, Jan. 26, 2012 | 11:59 p.m.
True or false: Concrete can float.
The answer: True, if formed properly.
A concrete canoe — one that will stay afloat unless it's tipped — was among the items on display this year at the World of Concrete trade show at the Las Vegas Convention Center.
One of the largest conventions to visit Las Vegas this year, the World of Concrete is expected to draw about 50,000 people from the construction industry.
Exhibits sprawled across all three halls of the convention center and spilled into the parking lot.
Exhibitors big and small trotted out a range of products, ranging from large heavy-duty vehicles like backhoes or skid loaders to chemical sealants to safety gloves and glasses. Tools of all types, including hammers, saws, jackhammers and floor polishers could also be found on display throughout the trade show floor.
And while the focus was on doing business, attendees also made time to watch their colleagues compete in brick-laying contests and truck obstacle courses.
With thousands of attendees and hundreds of exhibits, innovative tools and surprising uses of concrete lay hidden around every corner.
Here are five unexpected things you might run into at the World of Concrete:
Typically known more for its functional qualities than its decorative ones, several artists set up shop at the World of Concrete on Wednesday to show off the creative ways concrete can be used.
Desert landscapes, abstract images and other designs featuring splashes of color and three dimensional elements were stamped, carved, painted and sealed into bricks of concrete in the parking lot outside the Las Vegas Convention Center.
Nick Vinson, a decorative concrete specialist, said concrete designs blend artistic elements with the practicality of concrete. The decorated pieces are often installed in outdoor patios, on benches, by pools or around fireplaces, he said.
“You’re really only limited by your imagination,” he said. “What we’re doing is giving the look of another material, but with the durability and integrity of concrete. This is going to keep its color and not fade for much longer.”
Concrete, which is about three times as dense as water, normally doesn’t float. But for teams of engineering students at universities across the country, subverting this law of material science has become an annual challenge.
At the World of Concrete Wednesday, two senior civil engineering students from California Polytechnic State University stood proudly by a fully functioning canoe made of concrete.
The two students were representing their teammates, whose project was judged the best in the nation this year based on its design and performance by the American Society of Civil Engineers.
Artfully inlaid with a painted seascape featuring orca whales, clown fish and turtles, the canoe’s fanciful aesthetic belies the engineering acuity it takes to make it float.
The trick, Gary Gasperi said, is to use a combination of concrete mixtures packed with other materials that help lower the canoe’s overall density.
“We used six mixtures to change the properties of the concrete and packed it with lightweight aggregates like hollow spheres and recycled glass,” he said. “The reason it floats is that it’s less dense than water.”
The canoe can comfortably seat six people, and took about 8,000 total man-hours to construct, Gasperi said.
Concrete made from paper
Next to a box containing shredded phone books, lottery tickets and recycled cellulose at the World of Concrete convention sat a pile of ordinary-looking bricks.
But lifting one of the bricks reveals its secret. Lighter than typical bricks, Greenstar Blox are manufactured using recycled materials — like the paper and shredded phone books on display at the Mason Greenstar booth.
The paper is mixed with additives and cement, and then cast into bricks, which retain the durability and integrity of regular bricks while providing enhanced insulation and energy efficiency.
“Papercrete,” as the product is generically known, has been around since the 1960s, Mason Greenstar spokesman Matt Hargrove said. But the material was mostly used for the construction of small, noncommercial products.
But waste in the construction industry drove the company’s founder to look for more environmentally friendly materials to build with.
“It’s been a backyard movement for decades,” Hargrove said. “We took it, started refining it and are trying to make it a commercially viable product.”
Heavy-duty vehicles weighing thousands of pounds and providing cutting edge construction technology dominated much of the convention floor at the World of Concrete. But at the Stiletto tool booth, the company looked to bring 21st century engineering to a time-tested piece of construction equipment.
The Tibone hammer is a single cast titanium tool that more efficiently distributes the force of impact than other hammers, Stiletto director of innovation Joel Allen said.
“Titanium has a more efficient transfer of your swing into the nail,” reducing recoil by up to 90 percent, Allen said. “They’re lighter, but do the work of a heavier hammer. It’s like a retirement plan for your elbow.”
The gunmetal gray hammers reduce wear on the elbow and weigh less, cutting down on lower back strain, he said.
They also feature magnetic heads for holding nails and a patented pry mechanism that allows workers to pull nails more easily.
The world's fastest brick layers
In a parking lot outside the Las Vegas Convention Center, large crowds packed bleachers and gathered around a makeshift arena to watch more than 40 competitors show off their mighty masonry skills Wednesday afternoon.
A feature event at the World of Concrete, the Spec Mix Bricklayer 500 pitted 21 teams of two against each other in a contest to see who could build a wall from scratch the fastest.
As one team member wheeled bricks and mortar along the assembly line, the other deftly worked a trowel, quickly laying the adhesive, slotting a brick into place and then repeating the process hundreds of times.
Competitors were allotted an hour to build a wall two bricks wide and 26 feet 8 inches long according to strict quality standards, with the fastest time taking first place.
A total of $100,000 in prizes was at stake, including a new Ford F-250 truck, mortar mixers and cash.