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The value to be used for Ef in the performance model is the arithmetic mean of all values obtained
during the test.
(2) Fatigue characteristics. Fatigue characteristics are presented as a plot of strain indicated
at the bottom surface of the specimen versus load repetitions at failure. Generally, the value of the
strain obtained during the first few load repetitions is the value to be plotted. If no direct means of
measuring strain is available, a strain value , may be computed using the expression
K-2. GRAPHICAL DETERMINATION OF FLEXURAL MODULUS FOR CHEMICALLY STABILIZED
SOILS (CRACKED SECTION). The procedure for determining a flexural modulus value for
chemically stabilized soils based on the cracked section concept involves the use of a relationship
between unconfined compressive strength and flexural modulus determined analytically. This
relationship is shown in Figure K-2. To use this relationship, specimens of the stabilized material
should be molded and tested following procedures indicated in ASTM D 1633. Values obtained
from the unconfined compression test can then be used to determine the values of the equivalent
cracked section modulus using Figure K-2.