chapter 3 rigid pavement - DOT On-Line Publications - Department ...

FFIWA TECHNICAL ADVISORY T 5080.17
July 14, 1994
(1) The following are recommended frequencies for
vibrators from AC1 309.
Diameter of Frequency
head, mm vibrations per minute
20 to 40 mm 10,000 - 15,000
30 to 65 mm 9,000 - 13,500
50 to 90 mm 8,000 - 12,000
8. CURING AND PROTECTION
a. Curing
(1) Curing is performed to maintain the presence
of water in concrete and to provide a
favorable temperature for cement hydration.
Methods of curing include ponding, spraying,
and fogging with water, wet covers such as
burlap, plastic sheets, membranes, and the
use of steam, electric forms, or insulation.
(2) The application rate of a particular curing
compound should be based on the rate
established during the approval process of
the curing compound. The AASHTO M 148
ineicates that a rate of application of
5m /liter should be used for testing the
material if no other rate is specified.
b. Protection
(1) Cold weather protection should be required
when it is expected that the daily mean
temperature for three consecutive days will
fall below 4O Celsius. The following
recommendations are for the minimum
temperatures for delivered concrete as they
appear in AASHTO M 157.
I--Air Minimum Concrete Temperature
Temperature Thin Thick
-1 to 7oc
-18O to -1OC
Below -18OC
3.10.17
16OC 10°C
18OC 13oc
. 21oc 16OC