Novel autoclaved fibre-cements utilising clay-brick waste

Connan, Hamish

Novel autoclaved fibre-cements utilising clay-brick waste

Connan, Hamish

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Publication Type:: Thesis
Issue Date:: 2007

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Field	Value	Language
dc.contributor.author	Connan, Hamish
dc.date.accessioned	2016-08-15T23:43:29Z
dc.date.available	2016-08-15T23:43:29Z
dc.date.issued	2007
dc.identifier.uri	http://hdl.handle.net/10453/49102
dc.description	University of Technology, Sydney. Faculty of Science.	en_AU
dc.description	NO FULL TEXT AVAILABLE. Access is restricted indefinitely. The hardcopy may be available for consultation at the UTS Library.
dc.description.abstract	NO FULL TEXT AVAILABLE. Access is restricted indefinitely. ----- Millions of tonnes of fired clay-brick waste are generated worldwide each year, a large portion of which is destined for landfill. This study is concerned with the utilisation of such alumina-silica rich material for the development of hydrothermally cured fibre-cement composites. The principal objective of this research was to establish the hydrothermal chemistry involved, and, evaluate the potential of using ground fired clay-brick as a raw material in the development and production of autoclaved fibre-cement prototypes. A carefully designed experimental program involving the evaluation of slurry, mortar and filter pad samples was conducted using a combination of analytical methods including XRD, DTA-TGA and NMR, in addition to physical characterisation. It was established that mullite, an aluminosilicate phase contained in fired clay-brick, promotes the formation of Al-substituted 1.1 run tobermorite, the main binder in most autoclaved calcium silicate products, with the release of Al₂O₃ occurring at or below 170°C. The formation of crystalline tobermorite was further enhanced by a reactive glassy phase and additional SiO₂, in the form of quartz and cristobalite, contained in fired clay-bricks. The addition of clay-brick fines up to 17.2 wt % was found to be beneficial to compressive strength; however, at Al/(Al+Si) ratios > 0.091 the formation of Al-(C-S-H) was promoted, decreasing the amount of Al-tobermorite. The study established that for the production of fibre-cement composites up to 12 wt % clay-brick fines could be used as quartz replacement in the cement-quartz matrix with no adverse effect to mechanical properties. With increasing amounts of Al-tobermorite formation, through the addition of clay-brick fines, the drying shrinkage and susceptibility to carbonation were found to decrease. Thus, the utilization of fired clay-brick waste for the production of hydrothermally cured fibre-cement products is a viable option for the future, affording economical, environmental and social benefits.	en_AU
dc.format	Thesis (PhD)
dc.language.iso	en_AU	en_AU
dc.rights	info:eu-repo/semantics/closedAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.title	Novel autoclaved fibre-cements utilising clay-brick waste	en_AU
dc.type	Thesis	en_AU
utslib.copyright.status	closed_access

Abstract:

NO FULL TEXT AVAILABLE. Access is restricted indefinitely. ----- Millions of tonnes of fired clay-brick waste are generated worldwide each year, a large portion of which is destined for landfill. This study is concerned with the utilisation of such alumina-silica rich material for the development of hydrothermally cured fibre-cement composites. The principal objective of this research was to establish the hydrothermal chemistry involved, and, evaluate the potential of using ground fired clay-brick as a raw material in the development and production of autoclaved fibre-cement prototypes. A carefully designed experimental program involving the evaluation of slurry, mortar and filter pad samples was conducted using a combination of analytical methods including XRD, DTA-TGA and NMR, in addition to physical characterisation. It was established that mullite, an aluminosilicate phase contained in fired clay-brick, promotes the formation of Al-substituted 1.1 run tobermorite, the main binder in most autoclaved calcium silicate products, with the release of Al₂O₃ occurring at or below 170°C. The formation of crystalline tobermorite was further enhanced by a reactive glassy phase and additional SiO₂, in the form of quartz and cristobalite, contained in fired clay-bricks. The addition of clay-brick fines up to 17.2 wt % was found to be beneficial to compressive strength; however, at Al/(Al+Si) ratios > 0.091 the formation of Al-(C-S-H) was promoted, decreasing the amount of Al-tobermorite. The study established that for the production of fibre-cement composites up to 12 wt % clay-brick fines could be used as quartz replacement in the cement-quartz matrix with no adverse effect to mechanical properties. With increasing amounts of Al-tobermorite formation, through the addition of clay-brick fines, the drying shrinkage and susceptibility to carbonation were found to decrease. Thus, the utilization of fired clay-brick waste for the production of hydrothermally cured fibre-cement products is a viable option for the future, affording economical, environmental and social benefits.

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http://hdl.handle.net/10453/49102