Evaluation of self consolidating concrete for bridge structure applications
SCC can overcome some of the problems encountered in the past in using high-slump conventional concrete.
The states are encouraged to have projects ready to use the technology before requesting workshops.A National Cooperative Highway Research Program (NCHRP), Project 18-12 Self-Consolidating Concrete for Precast, Prestressed Concrete Bridge Elements is scheduled for completion in 2008.The main objectives of this research are to develop guidelines for the use of self-consolidating concrete in precast, prestressed concrete bridge elements and to recommend relevant changes to the AASHTO LRFD Bridge Design and Construction Specifications.The experiment was so successful that the South Carolina Department of Transportation decided to use SCC for production of the five remaining drilled shafts.The high flowability through congested reinforcement, reduced amount of bleed water, more resistance to segregation, and extended workability (6 to 10 hours) combine to make SCC ideally suitable for drilled shaft construction.FHWA's Role The Federal Highway Administration (FHWA) continues to work with the states, researchers, concrete industry, admixture suppliers, and other partners in advancing SCC technology through research, development, deployment, and construction projects.
Many states are using SCC in beams and girders, bridge piers and pile caps, columns, walls, and drilled shafts.
Research States, in collaboration with the universities, have conducted studies to determine the feasibility and practicality of using locally available materials for developing SCC mixes for construction of highway projects.
The studies provide guidance for the design and testing of SCC mixes, prediction of time-dependent properties, and constructability considerations.
Drilled Shafts Researchers at Auburn University, AL, investigated the use of SCC in drilled shafts in 2003 and put SCC into practice in 2005 with the construction of drilled shafts for the U. 76/SC 9 bridge replacement over Lumber River in South Carolina.
The project started out with the experimental use of SCC in one of the drilled shafts under the IBRC program.
SCC cuts down on the labor needed and wear and tear on equipment and formwork because internal and external vibrators are not used.