ASTM C185-20 Standard Test Method for Air Content of Hydraulic Cement Mortar
The purpose of this test method is to determine whether or not the hydraulic cement under test meets the air-entraining or non-air-entraining requirements of the applicable hydraulic cement specification for which the test is being made. The air content of concrete is influenced by many factors other than the potential of the cement for air entrainment.
For testing freshly mixed mortar and masonry cement, have been designed and built in accordance with the following standards: DIN EN 459 T.2, DIN 18555 T.2, and ASTM C 185. To improve the workability of the mortar mixture, and to enhance the durability of mortar under conditions of frost and thawing weather conditions, admixtures are mixed in with the mortar during its preparation that promote the development of air voids. If properly applied, this technique can achieve an optimum in the feasible technological enhancement of the mixture of air and mortar in the total mortar volume. Frequent tests are essential in order to maintain at a constant level the air entrainment level that has been determined as optimal for a particular kind of mortar. This Air Entrainment Meter monitors the effects of air-entraining admixtures for the specified mortar mixtures. The purpose of this series of Air Entrainment Meters is to measure the air entrainment (air-void content) of fresh mortar. The pressure gauge gives a direct reading of the air content in per cent (%).
ASTM C231-09a Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
This test method covers the determination of the air content of freshly mixed concrete. The test determines the air content of freshly mixed concrete exclusive of any air that may exist inside voids within aggregate particles. For this reason, it is applicable to concrete made with relatively dense aggregate particles and requires the determination of the aggregate correction factor.
This test method and Test Method C 138/C 138M and C 173/C 173M provide pressure, gravimetric, and volumetric procedures, respectively, for determining the air content of freshly mixed concrete. The pressure procedure of this test method gives substantially the same air contents as the other two test methods for concretes made with dense aggregates.
The air content of hardened concrete may be either higher or lower than that determined by this test method. This depends upon the methods and amount of consolidation effort applied to the concrete from which the hardened concrete specimen is taken; uniformity and stability of the air bubbles in the fresh and hardened concrete; accuracy of the microscopic examination, if used; time of comparison; environmental exposure; stage in the delivery, placement, and consolidation processes at which the air content of the unhardened concrete is determined, that is, before or after the concrete goes through a pump; and other factors.
