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Applications of pseudo-ductile engineered cementitious composites for construction industry /Cheung, Kwok Fai. January 2004 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 314-315). Also available in electronic version. Access restricted to campus users.
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Investigation of concrete components with a pseudo-ductile layer /Cheung, Yin Nee. January 2004 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.
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Microstructure study of cementitious materials using resistivity measurement /Zhang, Jie. January 2008 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 177-196). Also available in electronic version.
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Diffraction Investigations of Cement Clinker and Tricalcium Silicate using Rietveld AnalysisJanuary 2003 (has links)
Cement is the world's most popular building material, yet surprisingly its composition is not fully understood. Due to the complex nature of cement constituents, there is currently no reliable method to quantitatively determine the composition of cement. Partly this arises from the fact that the crystal structure of the main component of cement, tricalcium silicate, has not been fully determined. There has been an increase in the use of Rietveld refinement of powder diffraction data for the analysis of cement in recent years. The method has emerged as a valuable tool for the quantitative determination of the composition of cement. A further advantage of the method is its ability to refine complex crystal structures, such as tricalcium silicate. Despite the increased application of this method, few publications exist concerning the evaluation or improvement of the method for the purpose of cement analysis. In this work, the Rietveld method has been critically investigated as a tool for the identification and quantification of the different phases in cement clinker. Laboratory X-ray, synchrotron, neutron, and combined diffraction data are all used in the investigations. For the first time, comparisons of analysis results using various sources are made, rather than comparing the results from various methods. Inconsistencies in the results were found, and their causes were investigated and identified. The reliability of this method was shown to be dependent on the quality of the diffraction data, both in terms of the counting statistics and the resolution, and on the ability of the structures used in the Rietveld model to describe the phases in the sample. The only previously existing structural model for triclinic tricalcium silicate is shown, in this work, inadequate as a description of the form found in cement. Consequently, the triclinic crystal structures of tricalcium silicate were re-investigated. Using synchrotron powder diffraction data, the lattice dynamics during the T1-T2 transition were observed in detail for the first time. Superstructure reflections were observed for the two structures. The first model for the average sub-structure of the T2 form is presented. Structural modulation in the T1 form was re-investigated. The parent sub-structure, suitable for Rietveld refinement, corresponding modulation wave-vector, and superspace group of the superstructure, were identified.
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The characterization of Hong Kong sewage sludge for its ash utilization in cement production /Chan, Fai Yeung. January 2009 (has links)
Includes bibliographical references.
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Experimental approaches for determining rheological properties of cement-based extrudates /Shen, Bin. January 2003 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 120-125). Also available in electronic version. Access restricted to campus users.
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Diffraction Investigations of Cement Clinker and Tricalcium Silicate using Rietveld AnalysisJanuary 2003 (has links)
Cement is the world's most popular building material, yet surprisingly its composition is not fully understood. Due to the complex nature of cement constituents, there is currently no reliable method to quantitatively determine the composition of cement. Partly this arises from the fact that the crystal structure of the main component of cement, tricalcium silicate, has not been fully determined. There has been an increase in the use of Rietveld refinement of powder diffraction data for the analysis of cement in recent years. The method has emerged as a valuable tool for the quantitative determination of the composition of cement. A further advantage of the method is its ability to refine complex crystal structures, such as tricalcium silicate. Despite the increased application of this method, few publications exist concerning the evaluation or improvement of the method for the purpose of cement analysis. In this work, the Rietveld method has been critically investigated as a tool for the identification and quantification of the different phases in cement clinker. Laboratory X-ray, synchrotron, neutron, and combined diffraction data are all used in the investigations. For the first time, comparisons of analysis results using various sources are made, rather than comparing the results from various methods. Inconsistencies in the results were found, and their causes were investigated and identified. The reliability of this method was shown to be dependent on the quality of the diffraction data, both in terms of the counting statistics and the resolution, and on the ability of the structures used in the Rietveld model to describe the phases in the sample. The only previously existing structural model for triclinic tricalcium silicate is shown, in this work, inadequate as a description of the form found in cement. Consequently, the triclinic crystal structures of tricalcium silicate were re-investigated. Using synchrotron powder diffraction data, the lattice dynamics during the T1-T2 transition were observed in detail for the first time. Superstructure reflections were observed for the two structures. The first model for the average sub-structure of the T2 form is presented. Structural modulation in the T1 form was re-investigated. The parent sub-structure, suitable for Rietveld refinement, corresponding modulation wave-vector, and superspace group of the superstructure, were identified.
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Diffraction investigations of cement clinker and tricalcium silicate using Rietveld analysis /Peterson, Vanessa Kate. January 2003 (has links)
Thesis (Ph. D.)--University of Technology, Sydney, 2003. / "Submited for the degree of Doctor of Philosophy, University of Technology, Sydney, Dept. of Chemistry, Materials and Forensic Sciences, August 2003" Bibliographic references: leaves 224-232.
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Research of magnesium phosphosilicate cement /Ding, Zhu. January 2005 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 212-220). Also available in electronic version. Access restricted to campus users.
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Impact of different materials on cracking of corrugated fibrecement sheetsMtsweni, Ntombikayise Beauty 07 July 2014 (has links)
The replacement of asbestos fibres with cellulose fibres in producing
corrugated fibre reinforced cement sheets by the Hatschek process resulted
in edge cracking for stacked sheets. This was due to the hydrophilic nature of
cellulose, which increases its tendency for exchanging water with the
surroundings. The drying process of corrugated sheets, in a stack, resulted in
shrinkage hence edge cracking along the sheet. To reduce the magnitude of
drying shrinkage and edge cracking potential, several mitigation strategies
were proposed including the surface treatment of cellulose fibres,
incorporation of wollastonite microfibres, addition of admixtures and
superplasticizers, kaolin inclusion as partial replacement of cement and
different exposure conditions. A fundamental understanding in mechanisms
behind volume changes and how cracks form was crucial for optimization of
the mitigation strategies.
This thesis initially used a review approach to understand the mechanisms
involved in different types of shrinkage and the role of different mitigation
techniques. The ultimate goal was to achieve lower drying shrinkage and
cracking risks in corrugated sheets along with reducing its economic impact.
As a result, surface treatment of cellulose fibres, based on transforming the
hydrophilic nature of cellulose to hydrophobic state, was investigated.
Furthermore, inclusion of wollastonite/ kaolin as partial replacement of
cement, were evaluated. Also, the potential of adding admixtures/
superplasticizers was explored. Finally, investigation on development of edge
cracks in stacked corrugated fibrecement sheets was conducted under
different exposure conditions.
The results and findings of this research showed no significant improvement
in permeability with cellulose surface treatment. Wollastonite microfibres
promoted pore discontinuity hence significant reduction in permeability thus lower drying shrinkage. However, the resultant sheets were brittle. By
reducing water content with addition of superplasticizers, density was
enhanced thus reducing volume change from drying and wetting. Kaolin
acted as internal restraint for shrinkage, refining the microstructure at the
interfacial transition zone thus increasing density and its pozzolanic reaction
enhanced mechanical properties. The inclusion of kaolin in the fibrecement
mix in conjunction with controlling exposure conditions managed to eliminate
edge cracking.
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