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152-millimeter (6- by 6-inch) cross section. After compaction, place a 152- by 533-millimeter (6-
by 21-inch) steel plate on the surface of the paving mixture and apply a leveling load of
8,896 Newtons (2,000 pounds) to the plate. Prepare six beam test specimens in the manner
b. After cooling, remove the beams from the molds and rotate 90 degrees so that the
smooth, parallel sides will become the top and bottom. Cement an L-shaped metal tab with quick-
setting epoxy glue to each 152- by 533-millimeter (6- by 21-inch) side of the beams on the beams'
neutral axes at midspan. The taps should be drilled for attachment of the LVDTS. Cure the beams
at 101.7 degrees Celsius (503 degrees Fahrenheit) for 4 days prior to testing.
E-6. TEST PROCEDURES.
a. Condition three specimens each at 10 and 241.7 degrees Celsius (50 and 75 3
degrees Fahrenheit) for at least 12 hours prior to testing. If testing occurs immediately after curing
the specimens at 101.7 degrees Celsius (503 degrees Fahrenheit) for 4 days, no additional
conditioning is required for the specimens tested at this temperature.
b. Place the specimen in the test machine as described in ASTM C 78. Place thin Teflon
strips at the point of contact between the test specimens and the load-applying and load-support
blocks. While the beams are being prepared for testing, place an additional support block at
midspan to prevent premature sagging of the beams. Remove this support block immediately prior
to the initiation of load application. Mount the LVDTs on laboratory stands on each side of the
beams, and attach the LVDTs to the L-shaped tabs on the sides of the beams. Connect the LVDTs
and load cell to the X-Y recorder. Make final adjustments and checks on specimens and test
equipment. Apply loading in accordance with ASTM C 78, omitting the initial 4,448-Newton
a. The modulus of rupture R is calculated from the following equation (from ASTM C 78):
R = modulus of rupture, MPa (psi)
P = maximum applied load, Newtons (pounds)
L = span length, millimeters (inches) (457 millimeters (18 inches))
b = average width of beam, millimeters (inches)
d = average depth (height) of beam, millimeters (inches)