Proposal of Plane Spacing Factor for Analyzing Air-Void Systems in Concrete

The efficiency of an air-void system is governed by the spacing of the voids, which determines the maximum distance that unstable water must travel to reach an escape boundary. The methods currently used for air-void analysis in hardened concrete are the modified point-count method and the linear-traverse method, which have been standardized and are described in detail in ASTM C 457. Both standardized techniques currently used for air-void analysis are time consuming and operator-dependant. This study proposes a plane spacing factor for evaluating the adequacy of air entrainment in a given hardened concrete section. To begin, the concept of plane spacing factor was explained and the equations for image analysis and ASTM C 457 Standard were derived. Then the proposed plane spacing factor was evaluated by experimental data. The results are as follow: The plane spacing factor is geometrically the shortest half-distance between peripheries of two air voids in the hardened cement paste, in which all air voids have equal diameter and are arranged in a plane lattice matrix. The only data required by the factor is the number of air voids and air void area per unit area obtained by ASTM standard or image analysis method. The proposed plane spacing factor is a simple concept but has a solid basis. The validation of the plane spacing factor by image analysis method was performed using experimental data performed in this study. The result indicates that the plane spacing factor is reasonable and compatible with the ASTM Standard spacing factor because of correlation analysis. Validation of the plane spacing factor by ASTM C 457 Standard was performed using the published data by Pigeon (12) in order to improve the level of objectivity. The result indicates that it is simple but accurate.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Jeong, Won-Kyong
  • Yun, Kyong-Ku
• Conference:
  • Transportation Research Board 86th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2007-1-21 to 2007-1-25
• Date: 2007

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; References; Tables;
• Pagination: 23p
• Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

• TRT Terms: Admixtures; Air voids; Cement paste; Concrete; Spacing; Standardization; Validation; Water
• Uncontrolled Terms: Air void analyzers; Hardened concrete
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01045565
• Record Type: Publication
• Report/Paper Numbers: 07-0601
• Files: TRIS, TRB
• Created Date: Apr 4 2007 11:14AM