ASTM C 138 - DENSITY (UNIT WEIGHT) OF CONCRETE Flashcards
Volume of Concrete
What is the DEFINITION of YIELD
Volume of concrete produced from known weights of component materials.
__ lbs
What must the scale for density measurments be accurate up to?
Accurate to 0.1 lbs
__ lbs/ft^3
What is a scales required MAXIMUM measuring capablities for densities of concrete?
160 lbs/ft3
5/8 inch +- __ inch
What is the DIAMETER of the tamping rod for concrete density?
5/8 inch
+- 1/16 inch diameter
How much LONGER must the tamping rod be than the depth of the mold?
4 inches longer
What is the TYPICAL AND MAXIMUM LENGTH of the tamping rod used for densities?
24 inches
3/4 inch - __ inch
What must the outside diameter of the vibration rod be between?
3/4 inch - 1 1/2 inch
9___ vibrations/minute
What is the MINIMUM vibrating frequency for an internal vibrator? (150 Hz)
9,000 vibrations/minute
How much longer must the vibrator be vs. the depth of the density container?
3 inches
Every __ years
How often must a vibrator be checked and verified?
Every 2 years
What must a vibrator be verified by?
Tachometer
If the Nominal Aggregate Size of the sample is 1 inch – What must the MINIMUM bucket volume be?
0.2 ft3
If the Nominal Aggregate Size of the sample is 1 1/2 inch – What must the MINIMUM bucket volume be?
0.4 ft3
If the Nominal Aggregate Size of the sample is 2 inch – What must the MINIMUM bucket volume be?
0.5 ft3
If the Nominal Aggregate Size of the sample is 3 inches – What must the MINIMUM bucket volume be?
1.0 ft3
If the Nominal Aggregate Size of the sample is 4 1/2 inch – What must the MINIMUM bucket volume be?
2.5 ft3
If the Nominal Aggregate Size of the sample is 6 inch – What must the MINIMUM bucket volume be?
3.5 ft3
M__, P__, G__
What are the THREE different types of materials that strike-off plates are made of?
1) Metal
2) Plastic
3) Glass
What is the MINIMUM thickness for a METAL strike-off plate?
1/4 inch
What is the MINIMUM thickness for a PLASTIC strike-off plate?
1/2 inch
What is the MINIMUM thickness for a GLASS strike-off plate?
1/2 inch
How much WIDER must the strike-off plate than the diameter of the density measure
2 inches
__ lbs +- 0.5 lbs
What is the mallet size required for a 1/2 ft3 measure AND SMALLER?
1.25 lbs +- 0.5lbs
__ lbs +- 0.5 ;bs
What is the mallet size required for a LARGER THAN 1/2 ft3 measure?
2.25 lbs
+- 0.5 lbs
Rodding, Vibration, or Both?
What method of consolidation must be used when measuring a slump of >3 inches?
Rodding
Rodding, Vibration, or Both?
What method of consolidation must be used when measuring a slump between 1 inch and 3 inches?
Vibration OR Rodding
Rodding, Vibration, or Both?
What method of consolidation must be used when measuring a slump of <1 inch?
Vibration
Do you wet sieve for denisty?
YES OR NO?
NO
What is the rodding procedure for a density measure of 1/2 ft3 or smaller?
Rod each layer 25 times
What is the rodding procedure for a density measure of 1 ft3?
Rod each layer 50 times
1 time for each __ in^2 of surface area
What is the rodding procedure for a density measures of larger than 1 ft3?
Rod each layer: 1 time for each 3 in2 of surface area
3 – when rodding –> __ when vibrating
What is the amount of lifts when rodding vs. when vibrating?
3 – lifts when rodding
2 – lifts when vibrating
When vibrating a measure for density – at how many DIFFERENT points do you insert the vibrator?
3 DIFFERENT points
_/8 inch
How much OVER the lip of the measure do you want your concrete to be?
(Inch)
1/8 inches
What do you do if you strike-off your measure and you DO NOT HAVE ENOUGH CONCRETE in your measure?
You MUST empty the measure and re-fill again
2/__ of measure
When sawing excess concrete off of measure – how far onto the plate do you place the strike-off plate onto the measure?
(In Fraction)
Across 2/3 of the measure
Back/Forward/Clean
Describe the strike-off procedure for density measure in 3 STEPS?
1) Place plate 2/3 onto measure and SAW BACK
2) Place place 2/3 onto measure and SAW FORWARD
3) Clean outside of the measure
