Title: Stabilized Air Void System in Superplasticized Concrete

Author(s): K. Baekmark, H. Hansen, and J. Reichart

Publication: Symposium Paper

Volume: 144

Issue:

Appears on pages(s): 177-190

Keywords: air-entraining agents; air entrainment; durability; slump; specific surface; stability; superplasticizers; water-reducing agents; Materials Research

DOI: 10.14359/4397

Date: 3/1/1994

Abstract:
The fact that a stable air-void system in concrete enhances its durability is well documented today. In Denmark, for example, all concrete to be used for exterior components is air-entrained. The main problem is to insure the stability of the air-void system in the concrete, independent of mixing time, transportation, consistency, fines content, and type of plasticizer or superplasticizer. A new type of air-entrainer has been developed that provides excellent performance in concrete containing a melamine sulfonate-type of superplasticizer. The concrete has a slump of more than 150 mm, and even after 60 min of transportation and pumping, the air-void content and air-void structure are still satisfactory. The air-entrainer is a combination of special surfactants chosen after a long series of tests. Carrying out such a range of tests within the short time available was possible only because of newly developed testing equipment, which made it possible to measure air content and air-void system parameters within 30 min while the concrete was still fresh. Results of the testing, in accordance with ASTM C 457, are presented.