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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 78 Abstracts search results
Document:
SP91-69
Date:
February 1, 1986
Author(s):
John P. H. Frearson and J. M. Uren
Publication:
Symposium Papers
Volume:
91
Abstract:
A second source of ground granulated blast-furnace slag ('slag') has become available in the UK, from Purfleet in South East England. The Purfleet slag has a slightly higher lime-silica ratio (c/s) and calcium content than the initial source at Scunthorpe. The slag has a potentially higher rate of hydration because of its chemical composition, but as a consequence can contain up to 30% by volume of merwinite crystallites included within its glass structure. The presence of these crystallites has been found to increase further the reactivity of the slag glass. Scanning election microscope (SEM) studies of concrete containing the slag have confirmed that the glassy particles containing merwinitic crystallites are more reactive than pure glass particles, also that an adequate supply of unreacted glass remains even in mature concrete. Testing of this merwinitic slag has shown no factors disadvantageous to slag reaction or performance and has confirmed that, when blended in appropriate proportions with Portland cement, it can for example, increase sulphate resistance and reduce expansion due to alkali-silica reaction. The results of the investigations reported are supported by a brief review of published literature which confirms that slag performance cannot be directly related to absolute glass content.
DOI:
10.14359/10128
SP91-70
D. M. Roy, A. Kumar, and J. P. Rhodes
Diffusion of sodium chloride, cesium chloride and simulated sea water solutions across and into cement pastes and mortars blended with granulated blast furnace slag has been studied. The temperatures of hydration and diffusion were varied between 23and 6O C. Phase chemistry, depth profiles of chloride, and ion migration measurements across paste membranes were used to follow reaction and diffusion of the salt solutions. It was observed that cement mortars containing the slag showed lower penetration depths of Cl- compared to the control portland cement mortars at normal or moderate temperatures. The diffusion of cesium or chloride ions was retarded significantly through the use of slag blending in pastes. The porosity was lower and pore structure was finer in the case of the blended cement, which is considered to be the primary reason for the beneficial effect on diffusion. Phase chemistry studies of blended slag-cement mortars indicated an absence of detrimental reaction products such as gypsum or brucite after exposure, but the presence of Friedel's salt (tetracalcium aluminate dichloride-lo-hydrate) was detected. Comparisons are also made with blends with fly ash, which also showed relatively favorable effects. The electronegative nature of portland cement was elucidated by Cs+ and Cl- migration in pastes.
10.14359/10129
SP91-71
G. G. Litvan and A. Meyer
Two experimental houses, one of ordinary portland cement (OPC) concrete and the other of granulated blast furnace slag cement (GBFSC) concrete, were built under carefully controlled and documented conditions. After 20 years of exposure, cores were analysed and significant carbonation to 40 mm in depth was detected by TGA and the wet chemical method. More significantly, little Ca(OH)2 was found in the GBFSC concrete at all levels, so that any reinforcing steel would have to be considered susceptible to corrosion. According to Hg porosimetry results, the porosity of OPC concrete decreased after carbonation but that of GBFSC remained unchanged. In addition, increased permeability of GBFSC concrete with carbonation was indicated by coarsening of the pores, and the tensile strength of the surface region suffered a large decrease.
10.14359/10130
SP91-72
D. W. S. Ho, I. Hinczak, J. J. Conroy, and R. K. Lewis
This paper explains the concept of water sorptivity as a measure of concrete quality and discusses the effect of interrupted curing (as distinct from continuous curing) on the quality of concrete. Results of a pilot study on concretes incorporating ground granulated blast-furnace slag either as a blend or as an intergrind are presented. It was found that the response to interrupted curing varied depending on the constituents of the concrete. Plain concrete (i.e. without chemical or mineral admixtures) with a 28-day strength of 28 MPa showed a very slow response to interrupted curing, but could be improved by the incorporation of slag or by specifying a higher 28-day strength.
10.14359/10131
SP91-73
Ion Ionescu and Traian Ispas
Properties of heavy and light-weight concretes prepared with binders based on slag and activated ashes were studied as follows : fresh concrete; strength of concrete hardened both at normal temperature and by heat treatment; permeability and resistance to freeze-thaw cycling; behaviour of some concrete elements under various working conditions; preparation some technico-economic aspects related to and use of binders and practical conclu-sions for design and manufacture
10.14359/10132
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