A Study on the Characteristics of Concrete with Fly Ash from Circulating Fluidized Bed Combustion

• Main Authors: Yi Chung Chen, 陳義中
• Other Authors: Howard Hwang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/65789886027010903375

碩士 === 國立宜蘭大學 === 建築與永續規劃研究所碩士班 === 99 === In this study, we applied circulating fluidized bed combustion (CFBC) fly ash into concrete, and then we performed experiments on properties of fresh concrete; we also performed experiments on microstructures, physical properties, mechanical properties, and durability properties of concrete to investigate the effects of CFBC fly ash on the characteristics of concrete. In the first part of this study, because CFBC fly ash itself is a strong alkaline material, we used CFBC fly ash as an alkaline activator to stimulate the potential bonding characteristics of slag, and we added 10%, 20% and 30% of CFBC fly ash into slag concrete. The experiment results showed that CFBC fly ash can effectively stimulate the bonding characteristics of slag, promote the formation of hydration products, reduce the total amount of void content, and increase densification of slag concrete. Although the development of compressive strength in early stage is a little bit slow, CFBC fly ash can effectively increase compressive strength in later stage, improve concrete resistance to erosion by chemical substances, and improve the degree of corrosion in reinforcement. On the other hands, CFBC fly ash may reduce the workability of concrete, and if slag concrete is exposed in a relatively high humidity environment for a long period of time, the concrete may exhibit expansion phenomena. The experiment results also showed that adding 20% of CFBC fly ash into slag concrete may produce the best characteristics of slag concrete. In the second part of this study, we used CFBC fly ash as a binder in concrete. We added 10%, 20% and 30% of CFBC fly ash into concrete as a replacement of binding material. The experiment results showed that adding more than 10% of CFBC fly ash may decrease the formation of hydration products, increase total porosity, reduce densification and compressive strength, and reduce a large extent of workability of concrete, but it may reduce the degrees of bleeding and improve resistance to sulfate attack. Thus, as far as the engineering property of concrete is concerned, adding 10% of CFBC fly ash into concrete as a replacement of binding material may produce the best results.