Strength and Ultrasonic Characteristics of Alkali-Activated Fly Ash-Slag Geopolymer Concrete after Exposure to Elevated Temperatures
Publication: Journal of Materials in Civil Engineering
Volume 28, Issue 2
Abstract
Geopolymer concrete is an environment-friendly building material which has attracted increasing interest in many fields as a replacement for conventional concrete. The main objective of this paper is to study the residual behaviors of the alkali-activated fly ash–slag geopolymer concrete (FSGC) under different heating temperatures and cooling regimes. Changes in weight, compressive strength and ultrasonic pulse velocity were firstly investigated. Then the wavelet packet technique was adopted to further analyze the measured ultrasonic signals in frequency domain. Finally, the microstructures were investigated by scanning electron microscopy. The results indicate that an increase in temperature makes the weight, compressive strength, and ultrasonic pulse velocity value of FSGC decrease, especially under extreme heat conditions. The deterioration of specimens cooled by watering is more obvious than that of specimens cooled naturally. Based on the experimental results, it can be concluded that the critical temperature for FSGC is 600°C, but this temperature may change with the contents of fly ash and slag. Also, with the increase of temperature and specimen damage, the higher frequency components of the signal attenuate steadily and signal energy stored in lower frequency bands increases. A wavelet packet energy spectrum-based index is sensitive to thermal damage, which can be used as a supplementary indicator to assess the damage degree of the heated FSGC. After high temperature exposure, FSGC undergoes distinct morphological destruction as confirmed by the developments of microcracks and the damaged aluminosilicate gel matrix.
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Acknowledgments
The authors would like to thank the National Natural Science Foundation of China (Grant Nos. 51208507 and 51378497) for the financial support.
References
Arioz, O. (2007). “Effects of elevated temperatures on properties of concrete.” Fire Saf. J., 42(8), 516–522.
Daubechies, I. (1992). Ten lectures on wavelets, Society for Industrial and Applied Mathematics, Philadelphia.
Deb, P. S., Nath, P., and Sarker, P. K. (2014). “The effects of ground granulated blast-furnace slag blending with fly ash and activator content on the workability and strength properties of geopolymer concrete cured at ambient temperature.” Mater. Des., 62, 32–39.
Deng, Y., Ding, Y. L., and Li, A. Q. (2010). “Feature extraction of acoustic emission signals for cable damage based on wavelet packet analysis.” J. Vib. Shock, 29(6), 155–158 (in Chinese).
Divya, K., and Rubina, C. (2007). “Mechanism of geopolymerization and factors influencing its development: A review.” J. Mater. Sci., 42(3), 729–746.
Ismail, I., Bernal, S. A., Provis, J. L., Hamdan, S., and Deventer, J. S. J. (2013). “Microstructural changes in alkali activated fly ash/slag geopolymers with sulfate exposure.” Mater. Struct., 46(3), 361–373.
Ismail, I., Bernal, S. A., Provis, J. L., Nicolas, R. S., Hamdan, S., and Deventer, J. S. J. (2014). “Modification of phase evolution in alkali-activated blast furnace slag by the incorporation of fly ash.” Cem. Concr. Compos., 45, 125–135.
Kong, D. L. Y., and Sanjayan, J. G. (2008). “Damage behavior of geopolymer composites exposed to elevated temperatures.” Cem. Concr. Compos., 30(10), 986–991.
Kong, D. L. Y., and Sanjayan, J. G. (2010). “Effect of elevated temperatures on geopolymer paste, mortar and concrete.” Cem. Concr. Res., 40(2), 334–339.
Kumar, S., Kumar, R., and Mehrotra, S. P. (2010). “Influence of granulated blast furnace slag on the reaction, structure and properties of fly ash based geopolymer.” J. Mater. Sci., 45(3), 607–615.
Law, S. S., Li, X. Y., Zhu, X. Q., and Chan, S. L. (2005). “Structural damage detection from wavelet packet sensitivity.” Eng. Struct., 27(9), 1339–1348.
Lee, N. K., and Lee, H. K. (2013). “Setting and mechanical properties of alkali-activated fly ash/slag concrete manufactured at room temperature.” Constr. Build. Mater., 47, 1201–1209.
Pan, Z., Sanjayan, J. G., and Rangan, B. V. (2009). “An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature.” J. Mater. Sci., 44(7), 1873–1880.
Partha, S. D., Pradip, N., and Prabir, K. S. (2013). “Strength and permeation properties of slag blended fly ash based geopolymer concrete.” Adv. Mater. Res., 651, 168–173.
Peng, G. F., Bian, S. H., Guo, Z. Q., Zhao, J., Peng, X. L., and Jiang, Y. C. (2008). “Effect of thermal shock due to rapid cooling on residual mechanical properties of fiber concrete exposed to high temperatures.” Constr. Build. Mater., 22(5), 948–955.
Puligilla, S., and Mondal, P. (2013). “Role of slag in microstructural development and hardening of fly ash-slag geopolymer.” Cem. Concr. Res., 43, 70–80.
Uysal, M. (2012). “Self-compacting concrete incorporating filler additives: Performance at high temperatures.” Constr. Build. Mater., 26(1), 701–706.
Yim, H. J., Kim, J. H., Park, S. J., and Kwak, H. G. (2012). “Characterization of thermally damaged concrete using a nonlinear ultrasonic method.” Cem. Concr. Res., 42(11), 1438–1446.
Zheng, W., Li, H., and Wang, Y. (2012). “Compressive behaviour of hybrid fiber-reinforced reactive powder concrete after high temperature.” Mater. Des., 41, 403–409.
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© 2015 American Society of Civil Engineers.
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Received: Jan 8, 2015
Accepted: Jun 23, 2015
Published online: Aug 11, 2015
Discussion open until: Jan 11, 2016
Published in print: Feb 1, 2016
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