Royal White Cement has developed a calcium sulfoaluminate (CSA) cement for the North American market, targeting agencies that specify very high early strength concrete for highway or runway pavement construction or repairs, plus customers seeking a CSA base for precast production or grout, shotcrete and underlayment applications.
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| The CSA Cement launch coincides with a new packaging design for RWC white cement and masonry mortar products. |
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“A major advantage of using CSA cement is that you can produce zero shrinkage or very low shrinkage materials,” according to Royal White Vice President of Sales & Marketing Art Pinto. “When in contact with water, CSA cement immediately begins to produce ettringite, a mineral that fills the pores of the cement matrix, making it a denser material; contributes to the mix gaining high early strength; and, creates a small amount of expansion. This expansion can be controlled and is very stable in the long term.”
Another factor that contributes to the strength development and very low shrinkage characteristics of CSA cement-based products is water demand, he adds, noting: “Typically, ordinary portland cement requires about 18 percent water to properly hydrate, the rest of the added water is for workability and to allow for handling and installation. CSA cement requires around 35 percent water to properly hydrate, this high water demand means that there is little extra water needed to make a workable mix, and very little water left in the material after initial set, leaving very few voids, hence very low shrinkage.”
Compared to conventional portland cement, CSA cement production reduces fuel consumption in the most energy-intensive phases, pyroprocessing and milling. Portland cement requires kiln temperatures of around 2,700°F, CSA cements require around 2,250°F.
RWC CSA Cement concrete reaches compressive strengths of 4,000, 6,000 and 10,000 psi at three hours, 24 hours and 28 days, respectively. The binder joins signature white portland and masonry cement offerings following approvals Royal White has attained from California Department of Transportation and the U.S. Air Force, plus private construction market activity in the Southwest and Mid-Atlantic. The producer is initially supplying RWC CSA Cement from its Houston and Philadelphia terminals, and will extend availability from sister facilities—Vancouver, B.C.; Long Beach and Stockton, Calif.; Lake Park, Fla.; Savannah, Ga.; Kansas City, Mo.; and, Chesapeake Va.—as market development progresses. The product will be offered in bulk plus super sacks and 50-lb. bags. — Royal White Cement Inc., Houston, 866/WCEMENT, 713/676-0000; www.royalwhitecement.com