EP 1110-2-12
30 Sep 95
Figure 3-1. Tensile strength range, RCC, MSA ≤ 1.5 inches, consistency < 30 seconds vibration, mortar
bedding
The joint strength can be improved by placing a layer
are used as the basis for determining the tensile
of high slump bedding mortar on each lift; however,
strength of RCC, the test results shall be reduced by a
the resulting joint strength is always somewhat less
strength reduction factor of 75 percent as recom-
than the parent concrete. The consistency of RCC
mended in Appendix E.
can also affect tensile strength with lower strength
values for harsh mixes with low paste contents.
d. Factors affecting tensile strength. The tensile
Refer to Chapter 2 for additional discussion of these
strength of RCC, as well as of conventionally placed
factors.
mass concrete, is dependent on many variables
including paste and aggregate strength, aggregate size,
(2) Inherent in some RCC mixes are certain
loading history, and load deformation rates. See
anisotropic material properties. In the RCC compac-
paragraph 3-9 concerning strain rate sensitivity and
tion process, the flatter coarse aggregate particles in
dynamic tensile strength.
these mixes have a tendency to align themselves in
the horizontal direction. When this occurs, the
(1) RCC differs from conventionally placed mass
strength of vertical cores will be less, and the strength
concrete due to the many horizontal planes of weak-
of horizontal cores greater than the average tensile
ness (construction joints) created during placement.
strength. The variance from average could be as high
RCC is placed and compacted in layers ranging from
as 20 percent, although in general these effects will
6 to 24 inches with each layer creating a joint with
tensile strength less than that of the parent concrete.
3-2
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