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Title: Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals

Abstract

The compressive strengths and structures of composites of aluminosilicate geopolymer with the synthetic cement minerals C{sub 3}S, beta-C{sub 2}S, C{sub 3}A and commercial OPC were investigated. All the composites showed lower strengths than the geopolymer and OPC paste alone. X-ray diffraction, {sup 29}Si and {sup 27}Al MAS NMR and SEM/EDS observations indicate that hydration of the cement minerals and OPC is hindered in the presence of geopolymer, even though sufficient water was present in the mix for hydration to occur. In the absence of SEM evidence for the formation of an impervious layer around the cement mineral grains, the poor strength development is suggested to be due to the retarded development of C-S-H because of the preferential removal from the system of available Si because geopolymer formation is more rapid than the hydration of the cement minerals. This possibility is supported by experiments in which the rate of geopolymer formation is retarded by the substitution of potassium for sodium, by the reduction of the alkali content of the geopolymer paste or by the addition of borate. In all these cases the strength of the OPC-geopolymer composite was increased, particularly by the combination of the borate additive with the potassium geopolymer,more » producing an OPC-geopolymer composite stronger than hydrated OPC paste alone.« less

Authors:
 [1];  [1]
  1. School of Chemical and Physical Sciences Victoria University of Wellington, P.O. Box 600 Wellington (New Zealand)
Publication Date:
OSTI Identifier:
21344763
Resource Type:
Journal Article
Journal Name:
Cement and Concrete Research
Additional Journal Information:
Journal Volume: 40; Journal Issue: 5; Other Information: DOI: 10.1016/j.cemconres.2009.12.003; PII: S0008-8846(09)00349-4; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Journal ID: ISSN 0008-8846
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BORATES; COMPRESSION STRENGTH; HYDRATION; LAYERS; MICROSTRUCTURE; MINERALS; NUCLEAR MAGNETIC RESONANCE; PORTLAND CEMENT; POTASSIUM; SCANNING ELECTRON MICROSCOPY; SODIUM; WATER; X-RAY DIFFRACTION; ALKALI METALS; BORON COMPOUNDS; BUILDING MATERIALS; CEMENTS; COHERENT SCATTERING; DIFFRACTION; ELECTRON MICROSCOPY; ELEMENTS; HYDROGEN COMPOUNDS; MAGNETIC RESONANCE; MATERIALS; MECHANICAL PROPERTIES; METALS; MICROSCOPY; OXYGEN COMPOUNDS; RESONANCE; SCATTERING; SOLVATION

Citation Formats

Tailby, Jonathan, E-mail: jmtailby@hotmail.co, and MacKenzie, Kenneth J.D. Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals. United States: N. p., 2010. Web. doi:10.1016/j.cemconres.2009.12.003.
Tailby, Jonathan, E-mail: jmtailby@hotmail.co, & MacKenzie, Kenneth J.D. Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals. United States. doi:10.1016/j.cemconres.2009.12.003.
Tailby, Jonathan, E-mail: jmtailby@hotmail.co, and MacKenzie, Kenneth J.D. Sat . "Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals". United States. doi:10.1016/j.cemconres.2009.12.003.
@article{osti_21344763,
title = {Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals},
author = {Tailby, Jonathan, E-mail: jmtailby@hotmail.co and MacKenzie, Kenneth J.D.},
abstractNote = {The compressive strengths and structures of composites of aluminosilicate geopolymer with the synthetic cement minerals C{sub 3}S, beta-C{sub 2}S, C{sub 3}A and commercial OPC were investigated. All the composites showed lower strengths than the geopolymer and OPC paste alone. X-ray diffraction, {sup 29}Si and {sup 27}Al MAS NMR and SEM/EDS observations indicate that hydration of the cement minerals and OPC is hindered in the presence of geopolymer, even though sufficient water was present in the mix for hydration to occur. In the absence of SEM evidence for the formation of an impervious layer around the cement mineral grains, the poor strength development is suggested to be due to the retarded development of C-S-H because of the preferential removal from the system of available Si because geopolymer formation is more rapid than the hydration of the cement minerals. This possibility is supported by experiments in which the rate of geopolymer formation is retarded by the substitution of potassium for sodium, by the reduction of the alkali content of the geopolymer paste or by the addition of borate. In all these cases the strength of the OPC-geopolymer composite was increased, particularly by the combination of the borate additive with the potassium geopolymer, producing an OPC-geopolymer composite stronger than hydrated OPC paste alone.},
doi = {10.1016/j.cemconres.2009.12.003},
journal = {Cement and Concrete Research},
issn = {0008-8846},
number = 5,
volume = 40,
place = {United States},
year = {2010},
month = {5}
}