Title: Orgin, Evolution, and Effects of the Air Void System in Concrete. Part 1 - Etrained Air in Unhardend Concrete

Author(s): Richard C. Mielenz, Vladimir E. Wolkodoff, James E. Backstrom, and Harry L. Flack

Publication: Journal Proceedings

Volume: 55

Issue: 7

Appears on pages(s): 95-121

Keywords: no keywords

DOI: 10.14359/11343

Date: 7/1/1958

Abstract:
Air in concrete originates in four general ways, producing "entrapped" and "entrained" voids which are differentiated by their spatial and pressure rela-onships to the surrounding water and solids. The action of air-entraining agents in modifying the void system in concrete is discussed. Once formed, the air void system deteriorates in characteristic ways, mainly by interchange of air between small bubbles and large, and by loss of a portion of the air during compaction of the concrete. Several factors determine the rate and extent of deterioration effected before hardening of the concrete are described. ’ The action of the air void system in improving workability and decreasing segregation and bleeding is discussed.