Title:
Influence of Measurement Technique on the Air-Void
Structure of Hardened Concrete
Author(s):
Tine Aarre
Publication:
Materials Journal
Volume:
92
Issue:
6
Appears on pages(s):
599-604
Keywords:
air-entrained concretes; air entrainment; concretes; freeze-thaw
durability; specific surface; tests.
DOI:
10.14359/9779
Date:
11/1/1995
Abstract:
The air-void structure in hardened concrete exposed to subzero tempera-tures has to fulfill certain requirements. A reliable estimation of the relevant air-void parameters is very important. Generally, polished plane sections or thin sections are applied for air void analysis of hardened concrete. This paper presents an investigation of the influence of the type of sample applied for air-void analysis of hardened concrete. Air-void measurements of ten different concretes are presented. For each concrete, three thin sections and three plane sections are made and analyzed according to ASTM C 457. The results showed that the air content measured on thin sections is generally lower than the air content measured on plane sections. A theoretical evaluation postulates that the finite thickness of thin sections leads to a systematic error in the determination of the air content of concrete. The results of the theoretical and experimental work correspond well. It is concluded that when thin sections are applied for air-void analysis, the apparent air content will be systematically lower than the true air content.