Title: Review of the Pore Structure of Cement Paste and Concrete and its Influence on Permeability

Author(s): J. F. Young

Publication: Symposium Paper

Volume: 108

Issue:

Appears on pages(s): 1-18

Keywords: admixtures; calcium chlorides; cement pastes; concretes; fly ash; hardened paste structure; permeability; porosity; slags; water-reducing agents; Materials Research

DOI: 10.14359/2136

Date: 8/1/1988

Abstract:
The permeability of hardened cement paste is reviewed with particular reference to the influence of pore structure. Permeability is usually modelled by applying D'Arcy's Law, although permeability measurements and pore size distribution determinations reveal the strong influence of large capillary pores (macropores) on flow through cement paste. The macropores form a continuous flow path within the paste. The effects of curing temperature, drying, and admixtures on permeability can be understood in terms of their influence on macropores. Paste containing fly ash shows anomalous behavior, which apparently arises from internal damage occurring during pore structure measurements. It appears that the presence of fly ash promotes the formation of a discontinuous macropore system that inhibits flow.