3.1.11
Nuclear gauges shall have been factory calibrated within 6 months of RCC
placement. The Contractor shall construct, at no additional costs to the
Government, three conventional concrete test blocks using RCC coarse
aggregates and RCC fine aggregate, and with dimensions 300 mm 12 inches
larger than the gauge dimensions. The concrete shall be formulated to have
densities of approximately 2100, 2300, and 2600 kg/cu m 130, 145, and 160
lb/cu ft using the RCC materials and so far as possible, similar relative
proportions. Completed blocks shall be weighed and measured to determine
unit weight. Gauge calibration constants shall be adjusted for performance
on these blocks at least 7 days prior to the evaluation of test strips.
The Contractor shall remedy any inconsistencies in gauge performance prior
to the start of RCC placement. After the start of RCC placement, gauges
shall be field recalibrated against cast blocks every 24 hours.
3.1.12
Vibrators
Internal vibrators of the proper size, frequency, and amplitude for the
work being performed as indicated in the chart below shall be used to
consolidate conventional concrete and the interface between conventional
concrete and RCC. The vibrators for the conventional concrete/RCC
interface shall consist of a minimum of four vibrators "gang-mounted" in a
line on the boom of a backhoe or similar chassis. The gang-mounted
vibrators shall be the large (80 to 150 mm) (3 to 6 inch) models of that
listed below:
HEAD
AMPLITUDE
APPLICATION
DIAMETER (mm)
FREQUENCY (VPM)
(mm)
RCC interface
80 to 150
7,000 to 10,500
0.75 to 1.50
General construction
50 to 90
8,000 to 12,000
0.65 to 1.25
Thin walls
32 to 65
9,000 to 13,500
0.50 to 1.00
HEAD
AMPLITUDE
APPLICATION
DIAMETER (in.)
FREQUENCY (VPM)
(in.)
RCC interface
3 to 6
7,000 to 10,500
0.03 to 0.06
General construction
2 to 3-1/2
8,000 to 12,000
0.025 to 0.05
Thin walls
1-1/4 to 2-1/2
9,000 to 13,500
0.02 to 0.04
The frequency and amplitude shall be determined by the Contractor, in the
presence of a Government representative in accordance with COE CRD-C 521.
3.1.13
[Slipforming Equipment
**************************************************************************
NOTE: Consult the materials engineer or the
concrete materials DM for whether slipforming is to
be allowed or required.
**************************************************************************
The slipforming equipment shall be capable of slipforming facing elements
as specified at a minimum rate of 7.5 mm/s 1.5 ft/min. The slip-former
shall have an automated guidance system which shall guide the slip-former
within the specified tolerances. The slipformer shall have the capability
of turning and guiding the form without damage to the RCC and facing
element. The slipform mold shall be at least 1 m 3 feet long to allow the
slipform to track easily and to minimize surface tearing caused by friction
SECTION 03701
Page 43
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