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Internal vibrators shall be used. The vibrator frequency shall be at least 9000
vibrations per minute while the vibrator is operating in the concrete. The diameter of a
round vibrator shall be no more than one fourth the diameter of the cylinder mold or
width of the beam mold. The combined length of the vibrator shaft and vibrating
element shall exceed the depth of the section being vibrated by at least 3 inches.
Give this one a try later!
Vibrators
,After consolidation, Strike-off the measure by pressing the strike-off plate on the top
surface of the measure to cover about two thirds of the surface and withdraw the
plate with a sawing motion to finish only the area originally covered. Then place the
plate on the top of the measure to cover the original two thirds of the surface and
advance it with a vertical pressure and a sawing motion to cover the whole surface of
the measure and continue to advance it until it slides completely off the measure.
Incline the plate and perform final strokes with the edge of the plate to produce a
smooth surface.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Strike-Off
A mallet with a rubber or rawhide head weighing 1.25 + or - 0.5 lb shall be used.
Give this one a try later!
Mallet
Relative yield (Ry) is the actual volume divided by the design volume. It can be used
to compare yields of different mixes regardless of the size of the load batched. In our
example, the producer had wanted to yield 5.0 cubic yards when she batched this
particular truck. She actually yielded 5.15 cubic yards. Therefore, the relative yield is:
Formula: Ry = Y / Yd
Y= Yield (Actual Volume)
Yd= Design Yield
Relative Yield Example:
= 5.15 yd.3 ÷ 5.0 yd.3
= 1.03
, The producer is yielding 3% more than her design. (A yield of 0.97 would mean 3%
less than the design.)
Note: If Ry is greater than 1.00 indicates an excess of concrete being produced
whereas a value less than 1.00 indicates the batch to be "Short" of its designed
volume.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Relative Yield
A flat straight bar of steel or other suitable metal at least one eighth inch thick (1/8")
and three quarters inch wide (3/4") by 12 inches long.
Give this one a try later!
Strike-Off Bar
Place the concrete in the measure using the scoop. Move the scoop around the
perimeter of the measure opening to ensure an even distribution of the concrete with
minimal segregation. Fill the measure in the number of layers required by the
consolidation method of either Rodding or Internal Vibration.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Procedure
Internal vibrators shall be used. The vibrator frequency shall be at least 9000
vibrations per minute while the vibrator is operating in the concrete. The diameter of a
round vibrator shall be no more than one fourth the diameter of the cylinder mold or
width of the beam mold. The combined length of the vibrator shaft and vibrating
element shall exceed the depth of the section being vibrated by at least 3 inches.
Give this one a try later!
Vibrators
,After consolidation, Strike-off the measure by pressing the strike-off plate on the top
surface of the measure to cover about two thirds of the surface and withdraw the
plate with a sawing motion to finish only the area originally covered. Then place the
plate on the top of the measure to cover the original two thirds of the surface and
advance it with a vertical pressure and a sawing motion to cover the whole surface of
the measure and continue to advance it until it slides completely off the measure.
Incline the plate and perform final strokes with the edge of the plate to produce a
smooth surface.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Strike-Off
A mallet with a rubber or rawhide head weighing 1.25 + or - 0.5 lb shall be used.
Give this one a try later!
Mallet
Relative yield (Ry) is the actual volume divided by the design volume. It can be used
to compare yields of different mixes regardless of the size of the load batched. In our
example, the producer had wanted to yield 5.0 cubic yards when she batched this
particular truck. She actually yielded 5.15 cubic yards. Therefore, the relative yield is:
Formula: Ry = Y / Yd
Y= Yield (Actual Volume)
Yd= Design Yield
Relative Yield Example:
= 5.15 yd.3 ÷ 5.0 yd.3
= 1.03
, The producer is yielding 3% more than her design. (A yield of 0.97 would mean 3%
less than the design.)
Note: If Ry is greater than 1.00 indicates an excess of concrete being produced
whereas a value less than 1.00 indicates the batch to be "Short" of its designed
volume.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Relative Yield
A flat straight bar of steel or other suitable metal at least one eighth inch thick (1/8")
and three quarters inch wide (3/4") by 12 inches long.
Give this one a try later!
Strike-Off Bar
Place the concrete in the measure using the scoop. Move the scoop around the
perimeter of the measure opening to ensure an even distribution of the concrete with
minimal segregation. Fill the measure in the number of layers required by the
consolidation method of either Rodding or Internal Vibration.
Give this one a try later!
ASTM C138 Desity (Unit Weight), Yield & Air Content:
Procedure
