ASTM C231/C231M - Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method Flashcards
“This test method is intended for use with concretes and mortars made with relatively _____ aggregates”
Dense
TRUE or FALSE
Pressure method testing is not applicable to concretes made with lightweight aggregates, air-cooled blast-furnace slag, or aggregates of high porosity. In those cases, test method C173 should be used.
True.
ASTM C231 is intended for concretes and mortars made with relatively dense aggregates.
RODDING or VIBRATION
A - Concrete with slump less than 1”
B - Concrete with slump between 1” and 3”
C - Concrete with slump greater than 3”
A = Vibrate B = Vibrate or Rodding C = Rodding
If concrete slump is 2”, what method(s) of consolidation could you use?
Considering the method of consolidation you choose, how many layers of equal ______ do you place into the bowl?
You can consolidate using either
VIBRATION or RODDING method.
If VIBRATING, 2 layers of equal VOLUME
If RODDING, 3 layers of equal VOLUME
Before adding concrete to the measuring bowl, what must be done?
Dampen the bowl
When rodding “each upper layer, allow the rod to penetrate through the layer being rodded and into the layer below approximately ___ mm [ ___ in.]”
25 mm [1 in]
How may times should you rod each layer?
25
What is the weight of the mallet used with measures of 14 L [0.5 cu. ft.], or smaller?
What is the weight of the mallet used with measures greater than 14 L [0.5 cu. ft.]
1.25 lbs, +/-0.5 lbs
(for measures 14 L [0.5 cu. ft.], or smaller)
2.25 lbs, +/-0.5 lbs
(for measures greater than 14 L [0.5 cu. ft.])
When vibrating, “insert the vibrator at ___ different points for each layer of concrete.”
3
“In compacting the final layer, the vibrator shall penetrate into the underlying layer approximately
___ mm [ ___ in.]”
25 mm [ 1 in]
TRUE or FALSE
After final consolidation, “the measure must NOT contain a substantial excess or deficiency of concrete. An excess of concrete protruding approximately 9 mm [3/8 in.] above the top of the mold is optimum.
False
3 mm [ 1/8 in.] is optimum
TRUE or FALSE
Do not let the vibrator to touch, or rest on the bottom of the measure. It’s okay if the vibrator touches the sides of the measure as long as its not held there.
False
“do not allow the vibrator to rest on or touch the bottom OR sides of the measure”
For Vibrator information, C231 references C192/C192M
Per ASTM C192/C192M
“Vibrator frequency shall be at least _____ vibrations per minute while the vibrator is operating in the concrete.”
9000 vibrations per minute
For Vibrator information, C231 references C192/C192M
Per ASTM C192/C192M
“Diameter of a round vibrator shall be no more than ____ the diameter of the cylinder mold or ____ the width of the beam or prism mold.”
1/4 the diameter of a cylinder mold
1/4 the width of the beam or prism mold
Tamping Rod shall be at least 4 inches greater than ________________, but not be greater than ____ in total length.
The depth of the measuring bowl.
24” in total length