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Rheological and Physical Properties of Magesium Oxide and Silica Fume-Modified Cement Mortars Cured at High Temperature

Published online by Cambridge University Press:  21 February 2011

Zenbe-e Nakagawa
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Elizabeth L. White
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Della M. Roy
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
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Abstract

Physical properties and placement characteristics of cementitious mortars have been studied for their potential as repository sealing materials. They contained various expansive agents and industrial by-products, and were investigated at curing temperatures up to 250° C, the upper limit of an emplacement site or generally of relevance in accelerated reaction studies. An expansive agent, magnesium oxide, and two industrial by-products, silica fume and granulated blast furnace slag have been used at different percentages in the mixtures. Excellent general performance, including very high strengths up to 240 MPa combined with very low intrinsic permeability <10−8 Darcy (μm2) were generated at 175°C on material having a viscosity of 5000 cP (mPa·s) at 38° C. One 1700 cP(mPa·s) material treated at 250°C had compressive strength >180 MPa and also <10−8 Darcy (μm2) permeability. MgO was found to accelerate formation of tobermorite and generally cause expansion; at 250° C expansion was also related to xonotlite formation.

Type
Research Article
Copyright
Copyright © Materials Research Society 1983

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References

REFERENCES

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