Design of High-performance Concrete Mixtures and Test Beams for a Bridge in Virginia

About the report:

The main objective of this study was to develop concretes with a compressive strength of 69 to 83 MPa (10,000 to 12,000 psi) at 28 days and a high early release strength (within 20 hr) exceeding 70% of the 28-day strength. The properties of the high-performance concretes (HPC) tested included compressive strength, flexural strength, splitting tensile strength, and permeability. Four prestressed concrete AASHTO Type II beams were fabricated with HPC at a prestressing plant and load tested to failure. This test program was undertaken to support the field application of HPC in Virginia. Results showed that high-strength and low-permeability air-entrained mixtures could be designed. Concretes with a 28-day strength exceeding 69 MPa (10,000 psi), a minimum release strength of 70% of the 28-day strength, and coulomb values below 1,500 at 28 days can be produced with a water-cementitious material ratio (W/CM) of about 0.30 or below. Achieving such a low W/CM requires large amounts of cementitious material, proper selection of aggregates, and high dosages of high-range water-reducing admixtures. Thorough mixing is necessary, and good construction practices must be followed during placement, consolidation, and curing. To achieve high early strengths, proper temperature management is also needed.

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