New Cowboys’ Stadium Rides on Cement-Stabilized Soils

The 2.3-million-square-foot Cowboy’s Stadium now under construction in Arlington, Texas, will be the largest enclosed stadium in the National Football League and the biggest domed structure in the world.

The list of firsts extends down to the pavement, where all 30,000 parking spaces serving the stadium will be built on cement-stabilized subgrade soils.

The soils are treated with a slurry that includes both cement and lime to meet the specifications of the City of Arlington, which requires both materials to modify and stabilize subgrades.

Delivering the materials in slurry form rather than as separate dry materials reduces cost and application time says TXI, which is supplying the slurry for soil stabilization and ready mixed concrete for the stadium structure.

“Developers like one product and one cost, while contractors like one application,” says Dan Richwine, quality control manager for TXI.

The construction process is similar to that for full-depth reclamation, says Richwine. The contractor preps the grade by shaping it for drainage and bringing it to proper elevation. The cement-lime slurry is sprayed from an applicator truck onto the surface of the grade. A reclaiming machine then mixes the slurry into the soils until a homogenous mixture is created. Once compacted and graded, the subgrade is ready for the final pavement surface.

Stadium construction began in 2007 and is expected to be completed for the 2009 football season.
Contact Greg Halsted

PCA Publishes New Standard on Concrete Walls

Prescriptive Design of Exterior Concrete Walls for One- and Two-Family Dwellings, the first ANSI-approved standard by the Portland Cement Association, is now available.

The new standard, also known as PCA 100-07, facilitates the use of cast-in-place concrete wall systems built with either removable or stay-in-place forms, such as insulating concrete forms (ICFs).  It applies to the construction of detached one- and two-family dwellings and townhouses.  In most cases it eliminates the need for builders to hire an engineer for the projects, saving thousands of dollars.

It was approved by PCA’s National Standards Development Committee utilizing the American National Standards Institute (ANSI) accredited voluntary consensus process.

PCA 100-07 provides prescriptive designs for the construction of cast-in-place concrete footings, foundation walls, and above-grade concrete exterior walls, both loadbearing and non-loadbearing.  The designs are based on the requirements of ASCE 7-05, Minimum Design Loads for Buildings and Other Structures, ACI 318-05, Building Code Requirements for Structural Concrete, and tests results.

Through a cooperative agreement between PCA and the American Iron and Steel Institute, it includes prescriptive details for connections between concrete walls and floor and roof systems of cold-formed steel framing.   In addition connection details between wood framing and concrete walls have been updated.
Contact Donn Thompson
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Florida Cement Consumption Expected to Worsen in 2008 and 2009

The already grim market conditions facing Florida’s cement market may worsen in 2008 and 2009 according to a recent PCA report.  PCA believes that Florida’s economy has already entered a recession, or soon will, led by the housing crisis that has temporarily put Florida’s economy in reverse—impacting job growth, consumer spending, nonresidential investment, and perhaps eventually tourism.

PCA expects Florida’s cement consumption will decline by nearly 10 percent during 2008 and another 1.7 percent in 2009.  However, an accelerated recovery is anticipated for 2010 and beyond.  U.S Bureau of Census reports expects Florida’s population to increase by 11 million persons by 2030, pushing the state’s cement consumption to 20 million metric tons, roughly a 68 percent increase over peak 2005 levels.
Contact Ed Sullivan

Sydney Tar Pond Cooling Pond Solidification Begins

The important first step of solidifying the cooling ponds at the Sydney Tar Ponds and Coke Ovens in Nova Scotia is currently underway.   This is the first phase of Canada’s largest contaminated site clean-up.  The Canadian Federal and Nova Scotia Provincial governments estimate the project will cost $400 million (CAD) and take up to ten years.  This includes the solidification/stabilization of nearly 600,000 cubic meters of contaminated sediment and soil with portland cement.

The cooling ponds project will stabilize and solidify a nearly 25,000 cubic meters of sludge.  The sludge, about 1.5 meters deep, is the consistency of toothpaste and is impacted by Total Petroleum Hydrocarbons (TPHs), Volatile Organic Compounds (VOCs), Polycyclic Aromatic Hydrocarbons (PAHs), and metals.

In mid-January, contractors started to solidify and stabilize the sludge, starting with a pilot-scale demonstration then moving on to full-scale solidification and stabilization. A temporary road made of slag will be constructed to give contractors the ability to reach every inch of sludge; the road will later become part of the cement mixture.

Sydney Tar Ponds is the site of a former steel plant, where 100 years of steel and coke production left more than a million tons of contaminated soil and sediment. Hazardous constituents include coal tars and poly-chlorinated byphenyls (PCBs). The Canadian government committed C$400 million to remediate the site over 10 years.  The cooling pond project is Nova Scotia’s first aboriginal set-aside. The project provided bidders with majority aboriginal ownership and control the opportunity to benefit from cleanup work and to gain skills and training needed to compete for other construction projects.
More at http://tarpondscleanup.ca/
Contact Chuck Wilk

Next Fortified Home Under Construction

One of the newest Fortified…for safer living® homes will be located in West Seattle, overlooking Puget Sound.  The 4,100 square-foot, three-bedroom, four-bath home, currently under construction, features insulating concrete forms (ICFs) by Amvic and is fortified to withstand seismic activity.

In addition, ICFs contributed to the home meeting or exceeding the new LEED for Homes program guidelines, created by the U.S. Green Building Council.

Fortified…for safer living is a new-home construction designation program of the Institute for Business & Home Safety (IBHS), a national non-profit organization established and supported by insurance company members.

“Fortified” techniques and construction materials raise a home’s overall disaster-resistance above the requirements of local building codes.