Title: Air Entrainment in the Presence of Superplasticizers

Author(s): G.G. Litvan

Publication: Journal Proceedings

Volume: 80

Issue: 4

Appears on pages(s): 326-331

Keywords: air-entraining agents; air entrainment; freeze-thaw durability;mortars (material); plasticizers; porosity;voids;water-reducing agents.

DOI: 10.14359/10856

Date: 7/1/1983

Abstract:
Air-entrained and plain mortar specimens (cement-sand ratio = 1:3, water-cement ratio =0.65) were prepared using a modified sulfonated polymer, a naphthalene-formaldehyde condensate, or a sulfonated melamine formaldehyde admixture at two levels of concentration. The air-void system determined by the linear traverse method, the pore size distribution obtained by mercury intrusion porosimetry, and frost resistance assessed by alternate freezing and thawing were compared with those of control mixes containing no superplasticizer. A large pore volume (N 0.3 to 2 pm) in the presence of an air-entraining admixture is assumed to be responsible for the improved frost resistance of cement paste. Superplasticizers eliminate large air voids visible under the microscope but do not significantly interfere with the action of air-entraining admixtures in the formation of small pores.