3.6.1
Initial Curing
Immediately after finishing, shotcrete shall be kept continuously moist for
at least 3 days. One of the following materials or methods shall be used:
a. Ponding or continuous sprinkling.
b. Absorptive mat or fabric, sand, or other covering kept continuously
wet.
c. Curing Compounds. On natural gun or flash finishes, use the
coverage application requirement of 2.5 square meters per liter 100
square feet per gallon or twice the manufacturer's requirement,
whichever is less. Curing compounds shall not be used on any surfaces
against which additional shotcrete or other cementitious finishing
materials are to be bonded unless positive measures, such as
sandblasting, are taken to completely remove curing compounds prior to
the application of such additional materials.
3.6.2
Final Curing
Additional curing shall be provided immediately following the initial
curing and before the shotcrete has dried. One of the following materials
or methods shall be used:
a.
Continue the method used in initial curing.
b.
Application of impervious sheet material conforming to ASTM C 171.
3.6.3
Formed Surface
If forms are to be removed during curing period, one of the curing
materials or methods listed in paragraph INITIAL CURING shall be used
immediately. Such curing shall be continued for the remainder of the
curing period.
3.6.4
Duration of Curing
Curing shall be continued for the first 7 days after shotcreting or until
the specified [compressive] [flexural] strength of the in-place shotcrete
as determined by specimens obtained and tested in accordance with ASTM C
42/C 42M is achieved.
3.6.5
Temperature Considerations
The air temperature in contact with the shotcrete shall be continuously
maintained at a temperature above 5 degrees C 40 degrees F for at least [3
days after placement.] [[_____] days after placement if an accelerator is
used.] No shotcrete shall be applied when the concrete surface or air in
contact with the concrete surface is below 5 degrees C 40 degrees F.
3.7
TESTS
3.7.1
Strength Testing
**************************************************************************
NOTE: See the appropriate DM for locations of test
specimens and ages of tests. Air content tests
should only be specified on shotcrete produced by
the wet-mix process.
SECTION 03371
Page 17
Previous Page
