TO-340-A - Air Entrainment Meter – Type A
Entrainment of a small amount of air in cement concrete has been found to considerably improve the durability of concrete. The recommended limits specified for the air content are between 3% and 6.5%. Smaller percentages may result in deterioration taking place more quickly and larger percentages may reduce the strength without any improvement in the durability of concrete.
Further, when use of admixtures is made to increase workability of concrete, the air content should be checked to ensure that the percentage of air remains between 1% and 2% for optimum performance of the concrete structure.