The National Academies

NCHRP IDEA 20-30/IDEA 089 [Completed (IDEA)]

US-Specific Self-Compacting Concrete for Bridges
[ NCHRP 20-30 (NCHRP-IDEA) ]

  Project Data
Staff Responsibility: Dr. Inam Jawed

This project was aimed at adapting the self-compacting concrete technology for the U.S. market using domestic concrete materials and practice for use in highway structures. The experimental work focused on designing self-compacting concrete mix formulations with desired workability, segregation resistance, and deformability as well as testing for standard mechanical properties of the hardened concrete. Following a literature review, materials and equipment were selected and laboratory tests were performed to determine formulations that satisfied the filling and passing requirements for self-compacted concrete. All selected formulations contained fly ash and a superplasticizer. Tests on fresh mixes confirmed the flowability required for self-compacting concrete (Figure 1). However, the concrete mixes showed sensitivity to the mixing sequence. Consequently, tests were conducted to establish a mixing sequence for producing the most reliable and consistent results. Compressive strength tests showed rapid gain in strength: 3-day strengths approximated 80% of the 28-day strengths. The 28-day compressive strengths were almost 100 percent higher than those for conventional concrete. The modulus of elasticity tests showed an increase of about 30-45 percent over conventional concrete. The freeze-thaw resistance tests showed durability factors in the range of 87-98 percent. The segregation tendency of self consolidating concrete can be controlled by controlling the amount of superplasticizers. The higher unit cost of self-consolidating concrete (about 50 percent higher than conventional concrete) is largely offset by the use of less material and increased durability. The final report is available from the National Technical Information Service (NTIS # PB 2005-109494).
The final report for this IDEA project can be found at:

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