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Rapid Set Low-P Cement Gains Traction

An October 2008 launch of CTS Cement Manufacturing Corp.'s low-permeability powder Rapid Set Low-P Cement targeted three markets, i.e., Missouri, Virgina,

An October 2008 launch of CTS Cement Manufacturing Corp.'s low-permeability powder Û Rapid Set Low-P Cement Û targeted three markets, i.e., Missouri, Virgina, and New York/New Jersey, enabling close monitoring and collaboration with the departments of transportation, agencies, engineers, and contractors to ensure a successful introduction, the company asserts. Initial application was most widespread in Missouri, where the Department of Transportation (MoDOT) adopted the new technology for overlay work performed in downtown St. Louis. While most state DOTs in need of low-permeability concrete and freeze/thaw durability require at least one winter exposure before approving its use, CTS's long-standing relationship with MoDOT prompted the state to come on board with Low-P's initial launch.

In 2009, MoDOT approved the use of Rapid Set Low-P Cement concrete in seven District 6 [St. Louis] bridge patching and overlay projects, as well as for 34 local state bridges covered by an on-call repairs contract. Also, last year, VA DOT used Low-P Cement concrete for bridge repairs; and, Port Authority of NY and NJ incorporated the product for partial and full-depth patching on bridge decks, joint repair, elevated sidewalk construction, and structural tunnel work.

Presently, MoDOT is moving forward with eight bridge repair and overlay projects in 2010, including three large jobs that specify Rapid Set Low-P Cement concrete to bid this spring. The product is supplied from CTS plants in Mexico, Mo., and Nazareth, Pa. In the near future, a facility in Juarez, Mexico, will serve as an additional source of the material.

OAvailable in 2,000-lb. super sacks and bulk, Rapid Set Low-P yields about 3 to 3.5 yards of concrete per 2,000 lb. when used in a typical mix design. It is suitable for fast and ultra-durable concrete repairs and overlays, the company asserts, providing low permeability, corrosion resistance, and high early strength. The fast-setting hydraulic cement mixed with water and aggregates produces extremely workable mixes ready for traffic in one to three hours, RS Low-P developers note; and, finished concrete exhibits excellent freeze-thaw resistance, achieving a durability factor of 99 after 300 cycles [ASTM C666].

The high-slump, nonsegregating formula reportedly offers an alternative to latex-modified concrete, microsilica, low-slump, and silica-fume concrete for fast-track bridge deck overlays, elevated deck repairs, pavement repairs, and general concrete projects requiring low chloride ion permeability, high sulfate resistance, corrosion protection, and/or fast strength gain. Although volumetric mixers have been producing latex-modified (low-permeability) concrete since the early 1960s, the company notes, Rapid Set Low-P Cement concrete offers the advantages of the former in addition to corrosion resistance for the price of LMC and perhaps as inexpensively as microsilica fume concrete.