| Summary: | 博士 === 國立臺灣海洋大學 === 材料工程研究所 === 106 === This study referenced the green option of cement formula detailed in the ISO 14000 life-cycle assessment (LCA) to explore the applicability of using different types of ash, including furnace slag, incinerator ash, fly ash, silicon ash and circulating fluidized bed co-firing ash, as the supplementary materials of green cement and evaluate their environmental-friendly carbon reduction and economic benefits.
Limitations in the application of supplementary cement have been highlighted in previous studies and practical utilization. Specifically, only a limited amount can be added. For example, ASTM C595/C595M13 standards limit fly ash content in green cement to not more than 40%. However, the outcomes of previous studies and literature reviews show that composite slag cement in various mixed modes can be used to completely substitute Portland cement. When comparing with Portland cement， the environmental and economic efficiency of composite ballast cement and conventional, composite slag cement can achieved a maximum of 97.5% and 41.4% reduction respectively in carbon emissions and cost. Incinerated waste ash after being washed to remove chlorine compounds and heavy metals can partially substitute cement as the green cement material or raw material for Portland cement. However, this type of ash has no environmental or economic benefits. Silicon ash as the green cement or composite slag cement containing Na2SiO3 and NaOH as alkaline activators has better construction efficiency, but it reduces carbon reduction efficiency and increases the construction cost. Therefore, the effects of ash as green cement material on the carbon reduction efficiency and construction cost must be considered in the application. A comprehensive evaluation of the carbon reduction and economic efficiency of different types of ash revealed that composite slag cement containing 50% circulating fluidized bed co-firing ash and 50% furnace slag achieved the optimal carbon reduction and economic efficiency.
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