Air Void Analyzer for Plastic Concrete

The two main test methods that measure the air content in plastic concrete are the pressure method and the volumetric or roll-a-meter method. Although these methods report the total air in the concrete, they do not distinguish between entrained air and entrapped air or the quality of the air void system. The quality of the air void system consists of the content, distribution, and size of the air bubbles in the concrete matrix. In order to analyze the quality of the air void system, a petrographic analysis is required on the hardened concrete. The downside of this procedure is that it requires analysis of hardened concrete under a microscope which is time consuming, expensive, and results are determined well after placement of the concrete. The air void analyzer (AVA) is a new device developed as an alternative to the petrographic method that promises to provide air void system properties in a more timely manner while the concrete is still in the plastic stage. The intent of this research was to first, evaluate the air void analyzer and compare results with the petrographic method to verify its results. Secondly, it was to correlate the use of various types of water reducing admixtures (WRA) with various types of air entraining admixtures (AEA) into a generalized declaration that would state which WRA and AEA is good at developing a quality air void system in concrete. In the initial course of this investigation, the AVA demonstrated it was incapable of reliably reproducing results from the same batch of concrete about 60 percent of the time. It was decided to end this study. This report presents the study findings.

• Record URL:
  http://www.ltrc.lsu.edu/pdf/2008/fr_436.pdf
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/16559
• Corporate Authors:

  Louisiana Transportation Research Center

  4101 Gourrier Avenue
  Baton Rouge, LA  United States  70808

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Eggers, John
• Publication Date: 2008-10

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Appendices; Figures; Photos;
• Pagination: 42p

Subject/Index Terms

• TRT Terms: Air entraining agents; Air voids; Fresh concrete; Technological innovations; Testing equipment; Water reducing agents
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01122971
• Record Type: Publication
• Report/Paper Numbers: FHWA/LA/08-436
• Contract Numbers: LTRC Project No. 05-1C; State Project No. 736-99-1
• Files: NTL, TRIS, USDOT
• Created Date: Mar 4 2009 4:39PM