Title: Effectiveness of Mineral Admixtures and Curing Regimes on Air Permeability of Concrete

Author(s): R. N. Swamy and A. A. Darwish

Publication: Symposium Paper

Volume: 170

Issue:

Appears on pages(s): 207-230

Keywords: Compressive strength; durability; mineral admixtures; permeability.

DOI: 10.14359/6823

Date: 7/1/1997

Abstract:
Permeability is now recognized to be one of the key properties influencing the durability of concrete structures. The focus of this paper is the determination of the role and effectiveness of combinations of pozzolanic and cementitious cement replacement materials on the air/gas permeability of concrete. The apparatus used to determine the gas permeability consisted of a permeability cell, and air was forced to flow only in the vertical direction. Six different concrete mixtures were used; all the mixtures had the same water-binder ratio of 0.45, but two different total cementitious contents of 350 kg/m3 and 450 kg/m3 were investigated. Fly ash or slag was used in combination with silica fume. The test specimens were exposed to three different curing conditions prior to carrying out the permeability test. The results show that air permeability of concrete is highly dependent on the curing history of the concrete. There was no well-defined correlation between air permeability and compressive strength, but a reasonable correlation existed between air permeability and the threshold pore parameter obtained from pore structure studies.