Aggregate Testing Limitations
This method of testing can be used on any type of concrete – lightweight, regular weight or heavy weight. It’s good for sieve aggregate that would be retained on a 1-1/2" sieve over a 1" sieve.
Important Steps in the Volumetric Test
After properly filling bowl using a tamping rod at least 4 inches greater than depth of measuring bowl, make sure to:
- Use strike-off bar (Steel - 1/8" x 3/4" x 12" or High-Density Plastic - 1/4" x 3/4" x 12").
- Record results to nearest .25 percent.
- Insert funnel and add 1 pint of water.
- Add a “selected amount” of alcohol (no correction factor needed with 2.4 pints of alcohol or less).
- Add water until the water can be seen in the neck.
- Remove funnel and add water until the bottom of meniscus is at the zero mark.
- Screw lid on tightly.
- Invert for 5-second intervals, minimum 45 seconds total.
- Roll for 1 minute at a 45 degree angle tilt completing 1/4 to 1/2 turns, back and forth vigorously.
- Unscrew cap, allow 2 min. to settle, and take initial reading to the nearest .25 percent.
- Tighten cap and repeat 1 minute roll, then loosen cap, let settle, and take second reading.
- If second reading does not differ more than .25 percent from initial reading, then second reading becomes the final reading.
- If second reading does differ more than .25 percent, a 3rd roll of 1 minute is required.
- If third reading does not differ more than .25 percent from second reading, then third reading becomes final reading.
NOTE: If the air content is greater than the 9 percent range of the meter, add water using a calibrated cup to bring the liquid level back up into the graduated cylinder. Record the number of calibrated cups used to calculate back in for the final air reading.
Reasons for Invalid Test
- If third reading still differs more than .25 percent from second reading, discard test and start new using more alcohol.
- If at any time during the inversion and rolling process liquid leaks, discard test and start over.
- If it takes more than 6 minutes for the liquid level to stabilize, discard test.
- If there is more foam in the neck than the equivalent of 2 percent air content divisions after inversion and rolling, discard test and use more alcohol.
- If when the test is complete, portions of undisturbed, tightly packed concrete (not sand) is found at the base of the bowl when the contents have been dumped out, discard test and repeat.