TOPICS IN CONCRETE TECHNOLOGY-CHARACTERISTICS OF AIR-VOID SYSTEMS

ENTRAINED AIR MUST BE DISTRIBUTED THROUGH THE PASTE AS SMALL BUBBLES; TO SERVE ITS PRINCIPAL PURPOSES, THE NUMBER OF BUBBLES PER UNIT VOLUME OF AIR OR MEAN BUBBLE SIZE IS A PRE-EMINENT CHARACTERISTICS. AT PRESENT, SPECIFIC SURFACE AREA, (55%) IS THE MOST USEFUL FUNCTION OF MEAN BUBBLE SIZE. DETREMINANTS OF 55A IN NEAT PASTE ARE: KIND AND DOSAGE OF AIR-ENTRAINING AGENT, DURATION OF STIRRING, STIRRER SPEED (SHEAR STRESS), AND PASTE VISCOSITY. BUBBLE SIZE DISTRIBUTION IS INDICATED APPROXIMATELY BY: A SPACING FACTOR COMPUTED FROM 55A PASTE CONTENT, AND AIR CONTENT. /PCA/

• Authors:
  • Powers, T C
• Publication Date: 0

Media Info

• Serial:
  • Portland Cement Assoc R & D Lab Bull
  • Issue Number: 0

Subject/Index Terms

• TRT Terms: Air content; Air entraining agents; Air voids; Bubbles; Entrained air; Mixing; Pastes; Shear stress; Spacing; Specific surface; Surfaces; Viscosity
• Uncontrolled Terms: Surface area
• Old TRIS Terms: Air voids content; Stirring
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00213615
• Record Type: Publication
• Source Agency: Portland Cement Association
• Report/Paper Numbers: No 174
• Files: TRIS
• Created Date: Jun 1 1970 12:00AM