Concrete Knowledge Center - Troubleshooting Surface Imperfections

 
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    What are Bug Holes (Blow Holes)?
     
    Bug holes (blow holes) are small regular or irregular cavities, usually not exceeding 15 mm (0.6 in.) in diameter, resulting from entrapment of air bubbles in the surface of formed concrete during placement and consolidation.
   
   
P3: Ordinary smooth-form, as-cast concrete with numerous evenly scattered bugholes. Most of them are in the 1/8 to 1/4-in. range.


P5: Bugholes as large as 1 in. across, seen in combination with a wide range of other sizes of voids, some of significant depth. This would qualify as a smooth-form finish only if bugholes larger than 3/4 in. are filled.
     
   

Full-text article links:

"Bugholes," Concrete Technology, Portland Cement Association, Skokie, IL, 1 p.

"Bugholes in Formed Concrete," ASCC Position Statement 8, American Society of Concrete Contractors, St. Louis, MO, 2003, 1 p.

Ford, J., "Troubleshooting Common Defects in Vertical Cast-in-Place Concrete," Concrete Construction, Dec. 1992, pp. 879-880.

Reading, T. J., "The Bughole Problem," ACI Journal, Mar. 1972, pp. 165-171.

Samuelsson, P., "Voids in Concrete Surfaces," ACI Journal, Nov. 1970, pp. 868-874.
     
   

Other references:

ACI Committee 309, Identification and Control of Visible Effects of Consolidation on Formed Concrete Surfaces (ACI 309.2R-98), American Concrete Institute, Farmington Hills, MI, 1998, pp. 6, 8-10.

Blake, L. S.; Kinnear, R. G.; and Murphy, W. E., "Symposium on Surface Treatment of In-Situ Concrete," Cement and Concrete Association, London, 1964, 27 pp. http://www.concrete.org.uk

Blowholes (Bugholes), Cement Concrete & Aggregates Australia, Sept. 2001, 2 pp.

Bugholes in Concrete Surfaces: Annotated Bibliography, Portland Cement Association, Skokie, IL, 2004, 4 pp.

Guide for Surface Finish of Formed Concrete, American Society of Concrete Contractors, St. Louis, MO, 1999, 50 pp.

Houston, B. J., "Methods of Reducing the Size and Number of Voids on Formed Concrete Surfaces," Technical Report No. 6-788, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, July 1967.

McGovern, M., "Smooth Moves," Concrete Construction, Sept. 1999, pp. 48-50.

Smoak, W. G., Guide to Concrete Repair, U.S. Department of the Interior, Bureau of Reclamation, 1998, 184 pp.

Thompson, M. S., "Blowholes in Concrete Surfaces," Concrete, (Published by The Concrete Society, London), Feb. 1969, pp. 64-69.