Curing of High-Performance Concrete: Phase 1 Study.
Curing of High-Performance Concrete: Phase 1 Study.
(615 K)
Carino, N. J.; Meeks, K. W.
NISTIR 6505; 39 p. April 2001.
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Order number: PB2000-105888
Keywords:
concretes; curing; high performance concrete; mortar;
statistical analysis; tensile strength
Abstract:
This report summarizes 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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899