The NRCA Leadership and Workforce Development Catalog now is available for download.

Air Content of Plastic and Hardened Concrete

To obtain a copy of a specific publication, users should contact the publication's publisher directly.

Abstract
Air meter tests performed by different operatiors on the same batch of plastic concrete have a 95% probability of being within 0/80% of the mean. Analysis of variance of linear traverse data revealed that this test has good precision, as long as the air content does not exceed 7%; both within-operator and between-operator variances were non-significant below this level of air. When air meter results are compared to the entrained air content of hardened concrete, as determined by the linear traverse test, there is a 95% probability that the maximum variation between the means of the two will not exceed 1.65%. There is esentially no change in the entrained air content between plastic and hardened concrete whether vibrated 3 seconds or 30 seconds. Compressive strength is directly related to the total air content; for each percent increase in total air, the compressive strength decreases about 400 psi.
Date
9/1981
Author(s)
Reidenouer, DR; Howe, RH
Page(s)
126-
Keyword(s)
air content; concrete; entrained air; entrapped air void; linear traverse analysis; variance analysis


Note: Documents in this section are provided as Adobe Acrobat PDF files. In order to print and view PDF files, the Adobe Acrobat Reader software/plugin, which runs on Microsoft Windows, Macintosh, OS/2 and various versions of UNIX, must be installed on your computer. Adobe Acrobat Reader is available for download as freeware from Adobe Acrobat's website. Please note that the resolution of on-screen versions is not as high as printed versions of PDF files.

Advertisement

Subscribe for Updates Join 25,000+ roofing professionals following NRCA

Subscribe to NRCA