Concrete Air Test – How To Determine Air Content In Concrete
Uses and Importance of ASTM C231 Procedure
ACI Concrete Air Meter Parts
Today, we’d like to demonstrate how to determine air content in concrete air test according to ASTM C231
Step 1: Equipment needed to determine air content in concrete air test
The tools required for this test are a rubber mallet weighing 1.25 ± 0.50 lbs, a syringe (water dropper), an 18-inch, 5/8 diameter tamping rod with hemispherical tips, a strike off plate that must be at least 1/8 inches thick and ¾ inches wide by 12 inches long, or a strike off bar, a scoop, a rag or sponge for cleaning, bucket of water that is also used for cleaning, and an ASTM C231 approved concrete air pressure meter.
Start the concrete air test to see how to determine air content in concrete air test according to ASTM C231
Step 2: Start the ASTM C231 procedure for the concrete air test
To get started you need to dampen in the interior of the concrete air meter pressure.
Step 3: Begin to fill concrete inside the concrete air meter bowl
Next you will place the first layer of concrete in the air pressure meter bowl in three equal layers by volume. Start by moving the scoop around the perimeter of the air pressure meter.
Step 4: Go ahead and fill the first layer of the air pressure meter 1/3 of the volume
Start by filling the concrete air pressure meter bowl with 1/3 by volume of concrete.
Step 5: Followed by rodding the first layer 25 times
Next you will rod the layer 25 times with the 5/8 inch tamping rod. Make sure it is throughout its depth, without forcefully striking the bottom. Also, to distribute the rods uniformly over the cross section of the concrete air meter pressure bowl.
Step 6: Next tap the outside of the concrete air pressure meter
Then tap the outside of the concrete air pressure meter bowl 10 to 15 times with a rubber mallet. Make sure to close the air voids left by the tamping rod.
Step 7: Then fill the bowl 2/3 of the volume
Next you will use a scoop to fill the second layer with 2/3 by volume of concrete.
Ensure you only have 1/3 the volume left in the air pressure meter when filling the last lift with concrete.
Step 8: Next you will rod the second layer 25 times
Then you will rod the layer 25 times, with the 5/8 inch tamping rod. Make sure you penetrate the first layer by about one inch.
Step 9: Then tap the outside of the air pressure meter bowl
Next you will tap the outside of the concrete air meter bowl 10 to 15 times with a rubber mallet. Remember to close the air voids left by the tamping rod.
Step 10: Start by filling the third layer in the concrete air meter
For the final layer, you will add enough concrete so as to fill the concrete air pressure meter. Keep in mind to avoid excessive overfilling.
Step 11: Next you will rod the third layer 25 times
Then you will rod the final layer 25 times, with the 5/8 inch tamping rod. Making sure you penetrate the second layer about one inch. Also, distribute the rods uniformly over the cross section of the air pressure meter.
Step 12: Then you will tap the outside of the air pressure meter
Next you will tap the outside of the pressure meter bowl 10 to 15 times with the rubber mallet. Ensuring to close the air voids left by the tamping rod.
Step 13: Next you will need to incline the strike off plate
Finally, you will place the strike off plate on the air pressure meter bowl approximately two thirds of the diameter then you will use the strike off plate to level the surface. Use a sawing motion to produce a smooth surface. Make sure to Incline the strike off plate and make several passes to produce a smooth surface.
Final Steps for Concrete Air Content Test Procedure
Step 14: Now you can start cleaning the rim of the concrete air meter
Then thoroughly clean the rim of the air pressure meter bowl to ensure an airtight seal.
Step 15: Then dampen the bottom of the air pressure meter cover
Next you will dampen the bottom of the cover where the O ring is located.
Step 16: You need to securely place the cover on the air pressure meter
Make sure to securely place the cover on top of the bowl. Then you need to fasten the clamps on opposite ends. Fasten the opposite ends of the clamps for example the North and South should be clamped first then East and West clamps second.
Step 17: Then check the main air valve
Next you need to make sure the main air valve is closed.
Step 18: Next you need to check the petcocks
Then you should make sure both petcocks are open.
Step 19: Then inject water into the air pressure cover
Next you need to use a syringe to inject water through one petcock until the water emerges from the opposite side. At that time, jar the air pressure meter gently until all the air is expelled.
ASTM C231 – The Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
Step 20: Then check bleeder valve and initial pressure line
Next you need to close the bleeder valve. Then you can pump air into the air chamber until the hand on the dial gauge is on the initial pressure line.
Step 21: Next make sure to stabilize air meter gauge and close petcocks
Then lightly tap to stabilize the air pressure meter gauge. Then you need to close both petcocks to keep the pressure inside the concrete air meter.
Step 22: Then to release the air pressure meter
Finally, with your hand pressed down on the main air valve between the air chamber and the air pot. At the same time you need to hit the sides of the pressure meter bowl with a rubber mallet.
Step 23: Now record the results
Lastly you should lightly tap the air pressure gauge to stabilize the reading. Once it is stabilized you need to make sure to record the results to the nearest 0.1%.
Request A Call From One Of Our Representatives
CONTACT US
Office Hours:
Monday-Friday: 7:00am–5:00pm
Saturday: 8:00am-4:00pm
Sunday: Closed
Chat With Us:
Leave a Reply