Grout tests shall be conducted by the Contractor in accordance with ASTM C
31/C 31M and ASTM C 39/C 39M. Test specimens of grout shall be prepared by
pouring grout into 152 by 305 mm 6 by 12 inch cylinder molds. Molds shall
be provided with a top cover plate so designed as to restrain grout
expansion and to permit escape of air and water. Not less than one set of
cylinders shall be collected during the placing of each group of 15 piles
or fraction thereof. One set shall consist of six cylinders of which three
cylinders shall be tested in 7 days and three cylinders at 28 days. Any
set of cylinders of which one or more cylinders test at 10 percent or more
below the required strength shall be cause for rejection of the pile group.
3.6
TEST PILES
3.6.1
Placement
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NOTE: Specify load tests when needed to confirm
design capacities. The requirement for performing
load tests would depend on the degree of variations
in subsoil conditions. A minimum of one test pile
should be load tested in each area of substantially
different subsoil conditions. The requirement of
performing the load tests under the direct
supervision of a registered Professional Engineer
may be waived at the discretion of the design agency.
NOTE: Insert the grout strength required at the
time the test load is applied which could be the
specified 28-day strength if Type III (high-early
strength) cement is used or 75 percent of the
specified 28-day strength if regular cement is used.
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Test piles shall be of the type and shall be placed in the manner specified
elsewhere in this section for all piling. The Government will use test
pile and load test data in addition to test reports on soil samples to
determine "calculated" pile tip elevations. Piles immediately adjacent to
the test pile shall be placed after placing test pile and prior to load
testing. Test piles that are located within the tolerances indicated for
all piles and provide a safe design capacity as determined by the results
of a satisfactory load test may be used in the finished work. Test loads
shall not be applied to the piles until the grout has obtained a minimum
strength of [_____] MPa psi.
3.6.2
Depth
For all test piles, the auger shall be withdrawn after reaching the
"calculated" tip elevation and before grout is pumped. The Contracting
Officer will be present to check the soil conditions and shall have the
right to increase the test pile length if soil conditions warrant. In such
cases, the Contracting Officer may require additional auger withdrawals
after drilling to the lower tip elevation. Such additional auger
withdrawals shall be included in the total number of auger withdrawals
made. The pile hole shall not be filled with grout until the Contracting
Officer has approved the final tip elevation.
SECTION 02465
Page 14
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