Abstract
Thermal insulation concrete with recycled coarse aggregate (RATIC) provides an excellent alternative to energy saving and the reuse of waste concrete in buildings. In this paper, experiments were conducted to investigate the mechanical properties of the RATIC material after exposure to elevated temperatures, including failure feature and residual strengths. The effects of temperatures and the replacement percentage of recycled coarse aggregate (RCA) on the compressive and tensile strengths of the RATIC were first assessed experimentally. Then, the formulas for both compressive and tensile strengths were developed as a function of temperatures using the regression analysis. The test results show that the RATIC is prone to explosive spalling due to the compact structure of cement paste and low thermal conductivity. The compressive strength of the RATIC increases slightly under the temperature of 400 °C and then decreases significantly with an increasing exposed temperature. In contrast, the splitting tensile strength of the RATIC decreases significantly after the material was exposed to a high temperature of 200 to 800 °C. With the increasing RCA percentage, the RATIC experiences more strength deterioration in tension than compression, while little difference was observed regarding thermal exposure and failure modes of the RATIC.
Kurzfassung
Wärmeisolierender Beton mit recycelten groben Aggregaten (RATIC) stellt eine exzellente Alternative zur Energieeinsparung sowie zur Wiederverwendung von Beton in Gebäuden dar. Für den vorliegenden Beitrag wurden Experimente ausgeführt, um die Versagensmerkmale und die Restfestigkeiten von RATIC-Materialien nach erhöhter Temperaturbeanspruchung zu untersuchen. Die Auswirkungen der Temperaturen und des Ersatzstoffprozentsatzes der recycelten groben Aggregate (RCA) auf die Druck- und Zugfestigkeiten des RATIC-Materials wurden zum ersten Mal experimentell bestimmt. Danach wurden die Formeln sowohl für die Druck-, als auch für die Zugfestigkeiten als Funktion der Temperatur mittels Regressionsanalyse entwickelt. Die Testergebnisse zeigen, dass das RATIC-Material anfällig für explosives Abplatzen ist, und zwar aufgrund der kompakten Struktur der Zementpaste und der geringen thermischen Leitfähigkeit. Die Druckfestigkeit des RATIC-Materials nimmt geringfügig unterhalb der Temperatur von 400 °C zu und nimmt signifikant mit erhöhter Temperatur, der das Material ausgesetzt wird, ab. Im Gegensatz nimmt die Abspaltungszugfestigkeit des RATIC-Materials signifikant ab, wenn das Material hohen Temperaturen von 200 bis 800 °C ausgesetzt wurde. Mit zunehmendem RCA-Prozentsatz erfährt das RATIC-Material eine deutlichere Verschlechterung der Zug- als der Druckeigenschaften, während nur eine geringe Differenz bezüglich der thermischen Beanspruchung und der Versagensarten des RATIC-Materials beobachtet wurde.
References
1 K. K.Sagoe-Crentsil, T.Brown, A. H.Taylor: Performance of concrete made with commercially produced coarse recycled concrete aggregate, Cement Concrete Research31 (2001), No. 5, pp. 707–71210.1016/S0008-8846(00)00476-2Search in Google Scholar
2 M.Tavakoli, P.Soroushian: Strengths of recycled aggregate concrete made using field-demolished concrete as aggregate, ACI Material Journal93 (1996), No. 2, pp. 182–19010.14359/9802Search in Google Scholar
3 L.Evangelista, J.de Brito: Mechanical behaviour of concrete made with fine recycled concrete aggregates, Cement and Concrete Composites29 (2007), pp. 397–40110.1016/j.cemconcomp.2006.12.004Search in Google Scholar
4 F. T.Olorunsogo, N.Padayachee: Performance of recycled aggregate concrete monitored by durability indexes, Cement Concrete Research32 (2002), pp. 179–18510.1016/S0008-8846(01)00653-6Search in Google Scholar
5 Q.Liu, J. Z.Xiao, Z. H.Sun: Experimental study on the failure mechanism of recycled concrete, Cement Concrete Research41 (2011), No. 10, pp. 1050–105710.1016/j.cemconres.2011.06.007Search in Google Scholar
6 J. Z.Xiao, J.Li, C.Zhang: Mechanical properties of recycled aggregate concrete under uniaxial loading, Cement Concrete Research35 (2005), No. 6, pp. 1187–119410.1016/j.cemconres.2004.09.020Search in Google Scholar
7 Y. Z.Liu, W. J.Wang, Y.Zhang, Z.Li: Mechanical properties of thermal insulation concrete with a high volume of glazed hollow beads, Magazine of Concrete Research67 (2015), No. 13, pp. 693–70610.1680/macr.14.00296Search in Google Scholar
8 W. J.Wang, L.Zhao, Y. Z.Liu, Z.Li: Mix design of recycled aggregate thermal insulation concrete with mineral admixtures, Magazine of Concrete Research10 (2014), No. 10, pp. 492–50410.1680/macr.13.00335Search in Google Scholar
9 W. J.Wang, L.Zhao, Y. Z.Liu, Z.Li: Mechanical properties and stress–strain relationship in axial compression for concrete with added glazed hollow beads and construction waste, Construction and building materials71 (2014), pp. 425–43410.1016/j.conbuildmat.2014.05.005Search in Google Scholar
10 G.Ma, Y.Zhang, Y. Z.Liu, Z.Li: Seismic behaviour of recycled aggregate thermal insulation concrete (Ratic) shear walls, Magazine of Concrete Research67 (2015), No. 3, pp. 145–6210.1680/macr.14.00143Search in Google Scholar
11 L.Zhao, W. J.Wang, Z.Li, Y. F.Chen: Microstructure and pore fractal dimensions of recycled thermal insulation concrete, Materials Testing47 (2015), No. 4, pp. 349–35910.3139/120.110713Search in Google Scholar
12 Y. F.Chang, Y. H.Chen, M. S.Sheu, G. C.Yao: Residual stress–strain relationship for concrete after exposure to high temperatures, Cement and Concrete Composites36 (2006), pp. 1999–200510.1016/j.cemconres.2006.05.029Search in Google Scholar
13 U.Schneider: Concrete at high temperatures – A general review, Fire Safety Journal13 (1988), pp. 55–6810.1016/0379-7112(88)90033-1Search in Google Scholar
14 B.Georgali, P. E.Tsakiridis: Microstructure of fire-damaged concrete – A case study, Cement and Concrete Composites27 (2005), pp. 255–25910.1016/j.cemconcomp.2004.02.022Search in Google Scholar
15 M.Castellote, C.Alonso, C.Andrade, X.Turrillas, J.Campo: Composition and microstructural changes of cement pastes upon heating, as studied by neutron diffraction, Cement Concrete Research34 (2004), pp. 1633–164410.1016/S0008-8846(03)00229-1Search in Google Scholar
16 H. F. W.Taylor, C.Famy, K. L.Scrivener: Delayed ettringite formation, Cement Concrete Research31 (2001), pp. 683–69310.1016/S0008-8846(01)00466-5Search in Google Scholar
17 Y. N.Chan, G. F.Peng, M.Anson: Residual strength and pore structure of high-strength concrete and normal strength concrete after exposure to high temperatures, Cement and Concrete Composites23 (1999), pp. 23–2710.1016/S0958-9465(98)00034-1Search in Google Scholar
18 G. A.Khoury: Compressive strength of concrete at high temperatures: Reassessment, Magazine of Concrete Research44 (1992), pp. 291–30910.1680/macr.1992.44.161.291Search in Google Scholar
19 G. A.Khoury: Effect of fire on concrete and concrete structures, Progress in Structural and Materials4 (2000), pp. 429–44710.1002/pse.51Search in Google Scholar
20 C. J.Zega, A. A.Di Maio: Recycled concrete exposed to high temperatures, Magazine of Concrete Research58 (2006), pp. 675–68210.1680/macr.2006.58.10.675Search in Google Scholar
21 C. J.Zega, A. A.Di Maio: Recycled concrete made with different natural coarse aggregates exposed to high temperature, Construction and Building Materials23 (2009), pp. 2047–205210.1016/j.conbuildmat.2008.08.017Search in Google Scholar
22 S.-C.Kou, C.-S.Poon, M.Etxeberria: Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures, Cement Concrete Research53 (2014), pp. 73–8210.1016/j.cemconcomp.2014.06.001Search in Google Scholar
23 J.Xiao, C.Zhang: Fire damage and residual strengths of recycled aggregate concrete, Key Engineering Materials348–349 (2007), pp. 937–94010.4028/www.scientific.net/KEM.348-349.937Search in Google Scholar
24 J. P. B.Vieira, J. R.Correia, J.de Brito: Post-fire residual mechanical properties of concrete made with recycled concrete coarse aggregates, Cement Concrete Research41 (2011), pp. 533–54110.1016/j.cemconres.2011.02.002Search in Google Scholar
25 G. M.Chen, Y. H.He, H.Yang, J. F.Chen, Y. C.Guo: Compressive behavior of steel fiber reinforced recycled aggregate concrete after exposure to elevated temperatures, Construction and Building Materials71 (2014), pp. 1–1510.1016/j.conbuildmat.2014.08.012Search in Google Scholar
26 GB/T 50081: Standard for test method of mechanical properties on ordinary concrete, Chinese Architecture and Building Press, Beijing, P. R. China (2002) (in Chinese)Search in Google Scholar
27 Y. S.Tai, H. H.Pan, Y. N.Kung: Mechanical properties of steel fiber reinforced reactive powder concrete following exposure to high temperature reaching 800 °C, Nuclear Engineering and Design241 (2011), No. 7, pp. 2416–242410.1016/j.nucengdes.2011.04.008Search in Google Scholar
28 A.Lau, M.Anson: Effect of high temperatures on high performance steel fibre reinforced concrete, Cement Concrete Research36 (2006), No. 9, pp. 1698–170710.1016/j.cemconres.2006.03.024Search in Google Scholar
29 M.Ozawa, S.Uchida, T.Kamada, H.Morimoto: Study of mechanisms of explosive spalling in high-strength concrete at high temperatures using acoustic emission, Construction and Building Materials37 (2012), No. 3, pp. 621–62810.1016/j.conbuildmat.2012.06.070Search in Google Scholar
30 Eurocode 2: Design of concrete structures – Part 1.2: General rules – Structural fire design, British Standards Institution, London, United Kingdom (2008)Search in Google Scholar
31 S. Y. N.Chan, G. F.Peng, M.Anson: Fire behavior of high-performance concrete made with silica fume at various moisture contents, ACI Materials Journal96 (1999), No. 3, pp. 405–40910.14359/640Search in Google Scholar
32 A. M.Rashad, Y.Bai, P. A. M.Basheer, N. C.Collier, N. B.Milestone: Chemical and mechanical stability of sodium sulfate activated slag after exposure to elevated temperature, Cement Concrete Research42 (2012), No. 2, pp. 333–34310.1016/j.cemconres.2011.10.007Search in Google Scholar
33 L. T.Phan: Fire performance of high strength concrete, A report of the state-of-the-art building and fire research laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland (2001)Search in Google Scholar
34 M.Bastami, M.Baghbadrani, F.Aslani: Performance of nano-silica modified high strength concrete at elevated temperatures, Construction and Building Materials68 (2014), pp. 402–40810.1016/j.conbuildmat.2014.06.026Search in Google Scholar
35 M. S.Abrams: Compressive strength of concrete at temperatures to 1600 °F, ACI SP 25, Temperature and Concrete, American Concrete Institute, Detroit, United States (1971)Search in Google Scholar
36 W.Li, Z.Guo: Experimental investigation of strength and deformation of concrete at elevated temperatures, Journal of Building Structures14 (1993), No. 1, pp. 8–16 (in Chinese) 10.14006/j.jzjgxb.1993.01.002Search in Google Scholar
37 L.Liu, L.Lv, Z.Liu, H.Wang: Investigation on the mechanical behavior of concrete at and after elevated temperatures, Building Science21 (2005), No. 3, pp. 16–20 (in Chinese)Search in Google Scholar
38 F.Jia: An experimental research on the compressive strength of heated concrete, Journal of Qingdao Institute of Architecture and Engineering18 (1997), No. 1, pp. 10–14 (in Chinese)Search in Google Scholar
39 C.Castillo, A. J.Durrani: Effect of transient high temperature on high-strength concrete, ACI Material Journal87 (1990), No. 1, pp. 47–5310.14359/2356Search in Google Scholar
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