New "green" building for the Utah Museum of Natural History features innovative concrete mix containing recycled slag and fly ash

The new building under construction for the Utah Museum of Natural History on the University of Utah campus is a "green" work in progress with environmentally conscious building initiatives that include a pervious concrete parking lot and sidewalks, a building skin made of locally harvested copper and rock products, a wind turbine, and a roof with sections of native-seeded plants. The 165,000 square-foot museum, nestled in the hillside of a 17-acre lot bisected by the Bonneville Shoreline Trail, is designed to inspire an appreciation for science and represent Utah's magnificent natural history, landscape, and future. The very walls of the building are being constructed with a one-of-a kind concrete that's a testament to local scientific innovation and the recycling of Utah's own local natural resources.

According to Will Hopkins, a principal for general contractor Big-D Construction, the initial project specifications called for slag cement due to its white color and recycled content value. But, no ready-mix company in Utah had developed a self-consolidating mix that contained slag cement. The experts at Jack B. Parson Companies stepped up to this challenge, designing an innovative self-consolidating concrete mix that combines Portland cement, slag, and Class F fly ash (a product recycled from coal-fired power plants).

Slag is a recycled material that comes as a byproduct from iron manufacturing. Its particle shape is more jagged than Portland cement particles, resulting in a less flowable mix. A fluid and flowable mix was especially important for the museum project because of the unique architecture of the building, which features walls in excess of thirty feet tall with high and congested reinforcing.

"We had to be innovative in our mix design," said Lou Nicoletti, quality control manager for Jack B. Parson Companies. "We knew that the best choice for this project would be a self-consolidating mix. We enhanced the originally prescribed mix by incorporating Class F fly ash to improve flowability and architectural appeal. The finished concrete mirrors the unique board forming system required for this project. In the end, adding fly ash made the concrete lighter, brighter, and more aesthetically pleasing."

Nicoletti reported that despite containing only 300 pounds of Portland cement in the mix design, the concrete has greatly exceeded its specified strength achieving a 10,000 PSI average. And, while hydration stabilizers -- which typically prolong the set time of cement in concrete -- have been added to the mix, workers have been able to strip forms in less than 12 hours after pouring.

Senior project manager for Big-D Construction, Leon Nelson, added, "One of the most significant aspects of the project is the team work involved. The main participants on this project are located across the country and everyone has done a great job of establishing a cooperative, problem- solving culture. We're honored to be a part of this project."

The new building for the museum, to be called The Rio Tinto Center, is scheduled to be one of the largest buildings in the Salt Lake Valley to receive the LEED ® Gold certification based on the U.S. Green Building Council rating system. The building will be completed in the fall of 2011 and will house the museum's 1.2-million-piece collection of rocks, fossils, and artifacts. Polshek Partnership designed the unique structure, the Utah firm Gillies Stransky Brems Smith is architect of record, Maltbie is exhibit fabricator, and Ralph Appelbaum Associates is exhibit designer.

About Staker Parson Companies:
Since 1952, Staker Parson Companies has worked to be the Preferred Source of quality rock products, concrete, asphalt, paving, and construction services throughout the Intermountain West. The company employs over 2,500 people at more than 50 locations in Utah, Idaho, Oregon, Nevada, and Arizona. From the roads you drive on to the parks you play in, you can count on the team at Staker Parson Companies to deliver quality products and projects in a safe, timely, and efficient manner. The federation of Staker Parson Companies includes Jack B. Parson Companies, Idaho Sand & Gravel, Co., Idaho Concrete Company, and Western Rock Products.