Curing of High-Performance Concrete for Strength: What Is Sufficient?
Curing of High-Performance Concrete for Strength: What
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.
high performance concrete; curing; drying; mortar;
tensile strength; concretes
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