Title: A Method for Determining the Air Content of Fresh and Hardened Concrete

Author(s): Robert P. Vellines and Tomas Ason

Publication: Journal Proceedings

Volume: 45

Issue: 5

Appears on pages(s): 665-671

Keywords: no keywords

DOI: 10.14359/12178

Date: 5/1/1949

Abstract:
A method and equipment are described for determining the air content of fresh and hardened concrete based on the principal that air entrained in concrete reacts to external pressures and that volume changes follow the gas laws. The air entrained in hardend concrete reacts to an external pressure in the same manner as an equal volume of air would if it were not surrounded by hardenend cement paste. The volume of the air in the specimen is proportional to the time required for a quantity of gas to escape through an orfice from a pressure of p1 to a pressure of p2 at a constant temperature.