Title: Influence of Early Curing on the Surface Permeability and Absorption of Silica Fume Concrete

Author(s): S. A. Austin, P. J. Robins, and A. S. S. Aleesa

Publication: Symposium Paper

Volume: 145

Issue:

Appears on pages(s): 883-900

Keywords: absorption; climate; compressive strength; curing; durability; environments; permeability; silica fume; tests; Materials Research

DOI: 10.14359/4418

Date: 5/1/1994

Abstract:
Reports on part of a substantial research program on the properties of condensed silica fume (CSF) concretes cured in temperate and hot climates carried out in the Department of Civil Engineering at Loughborough. Three strength grades, C25, C40, and C55, were investigated, with the CSF (10 percent) mixes proportioned to have workability and 28-day strengths equal to ordinary portland cement (OPC) control mixes (when water-cured). The research examined the effects of curing environments (temperate and hot), curing time (1, 2, 4, and 8 days), and curing method (water and polythene) on the near-surface air and water permeabilities and water absorption of the concretes between 14 and 180 days. All specimens were subjected to diurnal temperature/humidity cycles representative of either a temperate or hot arid climate, the latter by storing specimens after casting in an environmental room. The research demonstrated that curing environment and duration greatly influence the permeability of ordinary portland cement and CSF concretes and, therefore, their potential durability in terms of resisting carbonation and ingress of other aggressive mediums such as chlorides. The hot-curing environment was favorable to the early-age absorption and permeability of ordinary portland cement mixes, but was detrimental at later ages compared with concrete cured in a temperate climate. The early- and later-age durability properties of CSF concretes were improved by the hotter curing environment.