Materials 2013, 6(10), 4450-4461; doi:10.3390/ma6104450
Article

Mechanical and Microstructural Evaluations of Lightweight Aggregate Geopolymer Concrete before and after Exposed to Elevated Temperatures

Received: 5 September 2013; in revised form: 22 September 2013 / Accepted: 25 September 2013 / Published: 9 October 2013
(This article belongs to the Special Issue Construction Materials)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: This paper presents the mechanical and microstructural characteristics of a lightweight aggregate geopolymer concrete (LWAGC) synthesized by the alkali-activation of a fly ash source (FA) before and after being exposed to elevated temperatures, ranging from 100 to 800 °C. The results show that the LWAGC unexposed to the elevated temperatures possesses a good strength-to-weight ratio compared with other LWAGCs available in the published literature. The unexposed LWAGC also shows an excellent strength development versus aging times, up to 365 days. For the exposed LWAGC to the elevated temperatures of 100 to 800 °C, the results illustrate that the concretes gain compressive strength after being exposed to elevated temperatures of 100, 200 and 300 °C. Afterward, the strength of the LWAGC started to deteriorate and decrease after being exposed to elevated temperatures of 400 °C, and up to 800 °C. Based on the mechanical strength results of the exposed LWAGCs to elevated temperatures of 100 °C to 800 °C, the relationship between the exposure temperature and the obtained residual compressive strength is statistically analyzed and achieved. In addition, the microstructure investigation of the unexposed LWAGC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ). However, this bonding is subjected to deterioration as the LWAGC is exposed to elevated temperatures of 400, 600 and 800 °C by increasing the microcrack content and swelling of the unreacted silicates.
Keywords: elevated temperatures; lightweight geopolymer concrete; thermal shrinkage; compressive strength; geopolymer
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MDPI and ACS Style

Abdulkareem, O.A.; Abdullah, M.M.A.B.; Hussin, K.; Ismail, K.N.; Binhussain, M. Mechanical and Microstructural Evaluations of Lightweight Aggregate Geopolymer Concrete before and after Exposed to Elevated Temperatures. Materials 2013, 6, 4450-4461.

AMA Style

Abdulkareem OA, Abdullah MMAB, Hussin K, Ismail KN, Binhussain M. Mechanical and Microstructural Evaluations of Lightweight Aggregate Geopolymer Concrete before and after Exposed to Elevated Temperatures. Materials. 2013; 6(10):4450-4461.

Chicago/Turabian Style

Abdulkareem, Omar A.; Abdullah, Mohd M.A.B.; Hussin, Kamarudin; Ismail, Khairul N.; Binhussain, Mohammed. 2013. "Mechanical and Microstructural Evaluations of Lightweight Aggregate Geopolymer Concrete before and after Exposed to Elevated Temperatures." Materials 6, no. 10: 4450-4461.

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