抄録
In this paper, the results of determination of the air content in fresh concrete by AE-55 indicator are described.
First of all, laboratory tests of the accuracy of this apparatus were made. The air contents of large number of concrete mixtures prepared in our laboratory were determined by using this indicator, and the results were compared with those obtained by the gravimetric and pressure methods, JIS method A 1116-1952 and A 1117-1952, respectively. Moreover, tests were made on 143 mixed concretes, in order to determine the accuracy and usability of this apparatus in the field.
These results are summarized as follows:
1) Each value of air content determined by AE-55 indicator method was 2.1% higher than that determined by the pressure method. This difference can be corrected with the contrrction of total volume occring in the mixing of alcohol and water contained in mortar.
2) Each value reported for the AE-55 indicator method is an average of two tests always made by two operators, whose values generally agreed within 0.5% of air content.
3) In the field's test, the total average of air content determined by the AE-55 indicator methad agreed within 0.3% of error.
