Title: Carbonation and Permeability of Blastfurnace Slag Cement Concretes From Field Structures

Author(s): G. J. Osborne

Publication: Symposium Paper

Volume: 114

Issue:

Appears on pages(s): 1209-1238

Keywords: blast furnace slag; carbonation; cement content; climate; compressive strength; concrete blocks; concretes; mix proportioning; curing; permeability; portland cements; structural members; Materials Research

DOI: 10.14359/2599

Date: 5/1/1989

Abstract:
Quality and performance of site-stored concrete blocks and structural-quality concretes from actual structures, where concretes contained different levels of ground granulated blast furnace slag as cement replacement material, have been assessed in terms of carbonation and gas or water permeability. First, 100 and 150 mm concrete cores were cut from site-stored concrete blocks and tested to assess the coring techniques and methods of measuring properties. These provided data on depths of carbonation and nitrogen, oxygen, and water permeability of ordinary portland cement and blast furnace slag cement concretes. Second, concrete cores were taken from actual structures. The two main factors influencing the depth of carbonation were the level of slag replacement for portland cement and the environmental conditions in which the concretes were situated. Carbonation was greater in the higher slag content cements especially if associated with a sheltered or drying microclimate. However, in general, gas and water permeability decreased with increased portland cement content and as slag replacement levels were reduced from 70 to 50 percent. Based upon these observations, appropriate slag contents are recommended for future use in various types of in situ concrete element.