Highway Panel Replacement—CSA Concrete in California 223 Highway Panel Replacement—CSA Concrete in California

In general, the U.S. highway system dates from the 1940s and 1950s. Some of these original pavements exist 60 years later. Needless to say, our Nation’s transportation infrastructure is in great need of improvements. According to the American Society of Civil Engineers ’ “2009 Report Card for America’s Infrastructure, ” our roads earn a D-minus, with 33 percent of the nation’s major roads in “poor or mediocre condition. ” Repair solutions must be cost-efficient, easy to implement, and long-lasting. The last 10 years have seen considerable growth in the use of proprietary and special repair cements for concrete pavements. Many of these products lend themselves to “fast track” construction techniques that allow reopening to traffic within 12 hours or less. These products achieve high early strengths by accelerating the portland cement hydration process for both Type I and Type III cements or through alternative cementitious reactions that include alkali-activated aluminosilicate cements, sulfoaluminate based cements, or magnesium phosphate cements. These products are typically labeled as “cementitious ” because their chemical reactions are inorganic, unlike the organic chemical reactions fundamental to epoxies and polymeric concretes. Unfortunately, most of these products are difficult to work with or uneconomical. The perfect material for highway panel replacement would be (1) cost effective, (2) easy to work with, and (3) have very early strength for early opening to traffic. The time required for a concrete mixture to achieve a minimum compressive strength influences the timing of opening a repaired road to service. Zia et al. (1) applied a criterion for a minimum compressive strength of 13.8 MPa (2,000 lbf/in2) in 6 hours for very early strength (VES) high-performance concrete. This paper discusses the use of a VES calcium sulfoaluminate concrete to meet these challenges and its use in the State of California