Manufacturing of sintered lightweight aggregate using high-carbon fly ash and its effect on the mechanical properties and microstructure of concrete

JOURNAL OF CLEANER PRODUCTION

卷:112

Article

Lo, Tommy Yiu²  Cui, Hongzhi¹  Memon, Shazim Ali³  Noguchi, Takafumi⁴ 

[1] Shenzhen Univ, Coll Civil Engn, Guangdong Prov Key Lab Durabil Marine Civil Engn, Shenzhen 518060, Peoples R China

[2] City Univ Hong Kong, Dept Civil & Architectural Engn, Hong Kong, Hong Kong, Peoples R China

[3] COMSATS Inst Informat Technol, Dept Civil Engn, Karachi, Pakistan

[4] Univ Tokyo, Grad Sch Engn, Dept Architecture, Tokyo 1138654, Japan

关键词: High-carbon fly ash;    Lightweight aggregate;    Temperature regime;    Concrete;    Mechanical properties;    Microstructure;   

DOI  :  10.1016/j.jclepro.2015.07.001

来源: Elsevier

【 摘 要 】

Fly ash is the largest source of industrial solid waste in China. Fly ash with its high content of unburned carbon has to be discarded in landfills and cause environmental problem. To reduce the environmental impacts, lightweight aggregate (LWA) was manufactured utilizing high-carbon fly ash (HCFA) (loss on ignition, LOI = similar to 16.3%). Trial tests were conducted on high-carbon fly ash lightweight aggregate (HCFA-LWA) in a laboratory electric furnace and in a manufacturer's batch furnace. A new temperature profile was proposed for the HCFA-LWA sintering process in which carbon served as a partial fuel substitute during the burning period, which can decrease the sintering period in the sintering stage of the LWA and save energy. Then, the mechanical properties and microstructure of lightweight concrete made with the HCFA-LWA were studied. The microscopic investigation of the interfacial transition zone showed that the cement paste infiltrated into the rough surface of the HCFA-LWA and improved the mechanical interlocking between the cement paste and the HCFA-LWA. Test results showed that the HCFA-LWA concrete developed 91% of the 28 d compressive strength within 7 d. The modulus of elasticity and tensile strength were also comparable to similar grades of LWA concretes. Therefore, HCFA-LWA can be used for structural applications. The utilization of HCFA-LWA in concrete would solve the waste disposal problems that are associated with fly ash and help reduce pollution to the environment. (C) 2015 Elsevier Ltd. All rights reserved.

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