ASTM C138 - Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete.
The air content and unit weight of the mixtures were measured in the fresh state using the method described in ASTM C231 and ASTM C138, respectively.(33,34) The fresh material was poured in the measuring bowl of the air meter apparatus in one single layer (due to the high flowability of the material) and flushed with the top edge. In some cases (e.g., epoxy grouts), external vibration was needed to further consolidate the material in the bowl. Immediately after this process, the mass of the bowl and material was taken, and the previously measured mass of the bowl was subtracted. The result was divided by the known volume of the bowl, resulting in the unit weight of the material. Then, the air meter apparatus was assembled, and the air content was measured according to ASTM C231.
The air content and unit weight of the mixtures were measured in the fresh state using the method described in ASTM C231 and ASTM C138, respectively.(33,34) The fresh material was poured in the measuring bowl of the air meter apparatus in one single layer (due to the high flowability of the material) and flushed with the top edge. In some cases (e.g., epoxy grouts), external vibration was needed to further consolidate the material in the bowl. Immediately after this process, the mass of the bowl and material was taken, and the previously measured mass of the bowl was subtracted. The result was divided by the known volume of the bowl, resulting in the unit weight of the material. Then, the air meter apparatus was assembled, and the air content was measured according to ASTM C231.
Now, let see how to test the air content by ASTM C231 - Air Content of Freshly Mixed Concrete by the Pressure Method:
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