Self consolidating concrete for precast prestressed concrete bridge elements

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others.Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities.The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board’s recognized objectivity and understanding of modern research practices.The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them.

SCC contributes to the construction of "Green Bridges." SCC facilitates the use of creative ways to prefabricate precast, prestressed concrete elements to achieve high production, while increasing plant safety and workers’ health and job satisfaction.

The replacement Tieton River Bridge consists of a two-span continuous structure with span lengths of 80 and 167 ft (24.4 and 50.9 m) for a total length of 247 ft (75.3 m). The specified concrete compressive strengths for the SCC precast girders were 4500 psi (31 MPa) at release of the prestressing strands and 5700 psi (39 MPa) at 28 days.

The bridge is 32 ft (9.8 m) wide and carries two lanes of traffic. The specifications required a slump flow of 25 to 28 in. The girders were lightly precompressed with twelve 0.6-in. (15.2-mm) diameter harped strands because WSDOT requires the use of the same type and number of girders in all spans of continuous bridges.

This, in turn, accelerates concrete placement and results in cost savings, less traffic disruption, and safer work zones.

SCC has the ability to flow into and completely fill intricate and complex formwork and to pass through and bond to congested reinforcement without segregation.

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