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Curing of High-Performance Concrete for Strength: What Is Sufficient?


pdf icon Curing of High-Performance Concrete for Strength: What Is Sufficient? (2420 K)
Carino, N. J.; Meeks, K. W.

Repair, Rehabilitation, and Maintenance of Concrete Structures, and Innovations in Design and Construction, 4th International Conference. Proceedings. American Concrete Institute (ACI). ACI SP 193. September 2000, Seoul, Korea, American Concrete Institute, Farmington Hills, MI, Malhotra, V. M., Editor(s), 1-36 pp, 2000.

Keywords:

high performance concrete; curing; drying; mortar; tensile strength; concretes

Abstract:

This paper reports the results of an exploratory study on the effects of curing duration on the variation of mortar strength with distance from the drying surface. A novel, notched cylindrical test specimen was adopted for measuring tensile strength at different depths. Two mortar mixtures with w/c of 0.30 and 0.45 were used; the former was assumed to be representative of the paste system in a high-performance concrete. Specimens were moist cured for (1, 3, or 7) d and then exposed to air at 25 deg C and 50% or 70% RH. The cylinders were sealed to simulate one-dimensional drying in a large member. Tensile strengths were measured at 28 d. Relationships between tensile strength and depth were compared with those of specimens continuously moist cured. The data tended to show that 1 d of moist curing might be sufficient to ensure adequate strength development at a depth of 25 mm from the exposed surface. The phenomenon of increasing strength with drying may have confounded the results, and recommendations for additional studies are provided.