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A platform for research: civil engineering, architecture and urbanism
Optimizing the use of recycled concrete fines in interground slag-cement
Ground granulated blast furnace slag (GGBFS) can be blended at fairly high proportions with ordinary portland cement to produce a material with excellent long-term strength properties. This combination of GGBFS and portland cement has the advantage of reducing both the amount of energy required for production as well as the amount of carbon dioxide released as a byproduct of the production. Unfortunately, when high proportions of slag (25 to 40 percent or more) are used, the early rate of reaction is slow. This can make the blended slag-cement unacceptable for some types of construction. Intergrinding the slag and portland cement clinker helps the early reaction rate somewhat, due to the preferential grinding of the portland cement clinker, but the reaction rate is still slower than that of portland cement alone. Fine particles of hydrated cement paste can act as an accelerator in concrete mixtures, and are present in various forms of recycled concrete. These fine particles are often undesirable - they must be disposed of at some cost while the larger particles in the recycled concrete can be more easily re-used. This paper presents a procedure for optimizing the addition of recycled concrete fines to interground slag-cement that allows for the further reduction of portland cement in the final mixture, and in some cases improves the early reaction rate of the blend (as compared to that of the interground slag-cement alone). Examples with two different recycled concrete materials are presented, and strength data is included to validate the benefits of the recycled concrete fines additions.
Optimizing the use of recycled concrete fines in interground slag-cement
Ground granulated blast furnace slag (GGBFS) can be blended at fairly high proportions with ordinary portland cement to produce a material with excellent long-term strength properties. This combination of GGBFS and portland cement has the advantage of reducing both the amount of energy required for production as well as the amount of carbon dioxide released as a byproduct of the production. Unfortunately, when high proportions of slag (25 to 40 percent or more) are used, the early rate of reaction is slow. This can make the blended slag-cement unacceptable for some types of construction. Intergrinding the slag and portland cement clinker helps the early reaction rate somewhat, due to the preferential grinding of the portland cement clinker, but the reaction rate is still slower than that of portland cement alone. Fine particles of hydrated cement paste can act as an accelerator in concrete mixtures, and are present in various forms of recycled concrete. These fine particles are often undesirable - they must be disposed of at some cost while the larger particles in the recycled concrete can be more easily re-used. This paper presents a procedure for optimizing the addition of recycled concrete fines to interground slag-cement that allows for the further reduction of portland cement in the final mixture, and in some cases improves the early reaction rate of the blend (as compared to that of the interground slag-cement alone). Examples with two different recycled concrete materials are presented, and strength data is included to validate the benefits of the recycled concrete fines additions.
Optimizing the use of recycled concrete fines in interground slag-cement
Optimierung des Einsatzes von Betonrecycling-Feinanteilen in Schlacken-Zement
Janssen, D.J. (author) / Vandenbossche, J.M. (author) / Whiting, N.M. (author) / Koubaa, A. (author)
2006
10 Seiten, 6 Bilder, 3 Tabellen, 3 Quellen
Conference paper
English
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