تحلیل اجزاء محدود و تجربی رفتار پیوستگی بین آرماتور و بتن حاوی الیاف، میکروسیلیس و نانوسیلیس

نوع مقاله : پژوهشی

نویسندگان

دانشگاه حکیم سبزواری

چکیده

رفتار پیوستگی بین آرماتور و بتن به جهت کاربرد روزافزون بتن مسلح در سازه های مختلف از جمله مهم ترین موضوعات مورد بررسی در دنیا می­باشد. در این پژوهش کـه به‌صورت آزمایشگاهی و مدل­سازی اجزاء محدود توسط نرم افزار ABAQUS انجام‌گرفته است، 36 طرح اختلاط بتنی با سه نوع رده مقاومتی سیمان و با درصدهای مختلف الیاف پلیمری، میکروسیلیس و نانوسیلیس ساخته شده و تاثیر این مواد بر رفتار پیوستگی بین آرماتورهای فولادی و بـتن و برخی خـواص مکـانیکی بـتن ازجمله مقاومـت فشـاری آن سنجیده شده است. روش استفاده از فنر غیرخطی نیز جهت مدل­سازی این رفتار پیوستگی ارائه شده و مورد تحلیل دینامیکی غیرخطی واقع شده است.

نتایج حاکی از هماهنگی قابل قبول مدل با نتایج آزمایشگاهی دارد. همچنین نشان می­دهد در این روش به دلیل وجود فنر، نحوه مش بندی المان­ها تاثیر ناچیزی بر نتایج پیوستگی- لغزش خواهد داشت. علاوه بر این، نتایج حاصل از آزمایشات و مقایسه آن با نتایج مدل­سازی نشان می­دهد که تاثیر الیاف در مقاومت پیوستگی ناچیز ولی در نحوه شکست بسیار موثر است. ترکیب توام میکرو و نانوسیلیس نیز می­تواند باعث بهبود مقاومت پیوستگی در حدود 20% گردد به طوری که استفاده از درصدی برابر از این دو ماده بهترین نتایج مقاومت پیوستگی را به دنبال داشته است.

کلیدواژه‌ها


عنوان مقاله [English]

Finite Element and Experimental Analysis of Bond Behavior Between Reinforcement and Concrete Containing Fibers, Silicafume and Nanosilica

نویسندگان [English]

  • Hamid Eskandari
  • Masoud Nematinejad
چکیده [English]

Bond behavior between reinforcement and concrete, due to increasing application of reinforced concrete, is one of the most important issues all over the world. In this research, which has been done experimentally and finite element (FE) modeling (using ABAQUS software), 36 mixtures are deigned considering three cement strength grades and various percentages of polymer fibers, silica fume and nano-silica. The effects of these admixtures on the bond behavior between concrete and reinforcement and also the compressive strength of concrete are investigated. The method of applying nonlinear spring (translator) for finite element modeling is presented and the model is analyzed using nonlinear dynamic analysis. The results yielded acceptable correlation between experimental and FE model. Since there are some translators in model, it can be mentioned that the results of bond slip are not influenced by meshing algorithm. Moreover, comparison of the experimental and FE results showed that while the effect of fiber in bond strength is negligible, it can be so effective in determining the failure shape. The combination of silica fume and nano silica can also improve the bond strength about 20% so that applying equal amount of these two admixtures may leads to the best strength results.

کلیدواژه‌ها [English]

  • Concrete
  • Fibers
  • Silica Fume
  • Nanosilica
  • Bond behavior
  • Finite element modeling
  • nonlinear dynamic analysis
  • Pull-out Test
[1]           C. H. Goodspeed, S. Vanikar, and R. A. Cook, "High-performance concrete defined for highway structures," Concrete International, vol. 18, pp. 62-67, 1996.
[2]           J. J. Park, S. T. Kang, K. T. Koh, and S. W. Kim, "Influence of the ingredients on the compressive strength of UHPC as a fundamental study to optimize the mixing proportion," in Proceedings of the international symposium on ultra-high performance concrete, structural materials and engineering series, 2008, pp. 105-12.
[3]           A. M. Neville, Properties of concrete, 1995.
[4]           K. J. Folliard and N. S. Berke, "Properties of high-performance concrete containing shrinkage-reducing admixture," Cement and Concrete Research, vol. 27, pp. 1357-1364, 1997.
[5]           M. Nili, A. Ehsani, and K. Shabani, "Influence of nano-SiO2 and micro-silica on concrete performance," in Proceedings Second International Conference on Sustainable Construction Materials and Technologies, 2010, pp. 1-5.
[6]           G. Li, "Properties of high-volume fly ash concrete incorporating nano-SiO 2," Cement and Concrete research, vol. 34, pp. 1043-1049, 2004.
[7]           A. Dunster, "Silica fume in concrete, Information Paper NIP 5/09," ed: IHS BRE Press, Garston, UK, 2009.
[8]           S. Sakka, Handbook of sol-gel science and technology. 1. Sol-gel processing vol. 1: Springer Science & Business Media, 2005.
[9]           K. M. A. Hossain and M. Lachemi, "Bond behavior of self-consolidating concrete with mineral and chemical admixtures," Journal of Materials in Civil Engineering, vol. 20, pp. 608-616, 2008.
[10]         A. Castel and S. J. Foster, "Bond strength between blended slag and Class F fly ash geopolymer concrete with steel reinforcement," Cement and Concrete Research, vol. 72, pp. 48-53, 2015.
[11]         S.-W. Kim, H.-D. Yun, W.-S. Park, and Y.-I. Jang, "Bond strength prediction for deformed steel rebar embedded in recycled coarse aggregate concrete," Materials & Design, vol. 83, pp. 257-269, 2015.
[12]         H. Zhai, P. Hagan, and D. Li, "Sample Size and Sample Strength Effects on Testing the Performance of Cable Bolts," 2016.
[13]         D. A. Abrams, "Tests of bond between concrete and steel," 1913.
[14]         T. Mylrea, "Bond and anchorage," in ACI Journal Proceedings, 1948.
[15]         D. Watstein, "Distribution of bond stress in concrete pull-out specimens," in ACI Journal Proceedings, 1947.
[16]         D. Darwin, M. L. Tholen, E. K. Idun, and J. Zuo, "Splice strength of high relative rib area reinforcing bars," ACI Structural Journal, vol. 93, 1996.
[17]         M. R. Esfahani and M. R. Kianoush, "Development/splice length of reinforcing bars," ACI structural journal, vol. 102, 2005.
[18]         P. M. Ferguson, R. D. Turpin, and J. N. Thompson, "Minimum bar spacing as a function of bond and shear strength," in ACI Journal Proceedings, 1954.
[19]         P. M. Ferguson, J. E. Breen, and J. N. Thompson, "Pullout tests on high strength reinforcing bars," in ACI Journal Proceedings, 1965.
[20]         H. H. Abrishami and D. Mitchell, "Analysis of bond stress distributions in pullout specimens," Journal of Structural Engineering, vol. 122, pp. 255-261, 1996.
[21]         J. Chinn, P. M. Ferguson, and J. N. Thompson, "Lapped splices in reinforced concrete beams," in ACI Journal Proceedings, 1955.
[22]         S. P. Shah, S. E. Swartz, and C. Ouyang, Fracture mechanics of concrete: applications of fracture mechanics to concrete, rock and other quasi-brittle materials: John Wiley & Sons, 1995.
[23]         S. Viwathanatepa, E. Popov, and V. Bertero, "Effects of generalized loadings on bond of reinforcing bars embedded in well confined concrete," in Report no. EERC 79/22, ed: Earthquake Engineering Center Berkeley, 1979.
[24]         P. Soroushian and K.-B. Choi, "Local bond of deformed bars with different diameters in confined concrete," ACI Structural Journal, vol. 86, 1989.
[25]         D. Darwin and E. K. Graham, "Effect of deformation height and spacing on bond strength of reinforcing bars," ACI Structural Journal, vol. 90, 1993.
[26]         J. Zuo and D. Darwin, "Splice strength of conventional and high relative rib area bars in normal and high-strength concrete," ACI structural Journal, vol. 97, 2000.
[27]         X. Song, Y. Wu, X. Gu, and C. Chen, "Bond behaviour of reinforcing steel bars in early age concrete," Construction and Building Materials, vol. 94, pp. 209-217, 2015.
[28]         L. A. Lutz and P. Gergely, "Mechanics of bond and slip of deformed bars in concrete," in ACI Journal Proceedings, 1967.
[29]         G. Rehm, "The fundamentals of bond between steel reinforcement and concrete," Deutsche association for steel reinforcement-concrete, p. 59, 1961.
[30]         S. Soretz and H. Holzenbein, "Influence of rib dimensions of reinforcing bars on bond and bendability," in ACI Journal Proceedings, 1979.
[31]         Y. Hao and H. Hao, "Pull-out behaviour of spiral-shaped steel fibres from normal-strength concrete matrix," Construction and Building Materials, vol. 139, pp. 34-44, 2017.
[32]         M. R. Esfahani, M. Lachemi, and M. R. Kianoush, "Top-bar effect of steel bars in self-consolidating concrete (SCC)," Cement and Concrete Composites, vol. 30, pp. 52-60, 2008.
[33]         T. P. Tassios, "Properties of bond between concrete and steel under load cycles idealizing seismic actions," Bulletin d’information du CEB,(131), pp. 65-122, 1979.
[34]         H. Stang, Z. Li, and S. Shah, "Pullout problem: stress versus fracture mechanical approach," Journal of Engineering Mechanics, vol. 116, pp. 2136-2150, 1990.
[35]         R. Tepfers, "Cracking of concrete cover along anchored deformed reinforcing bars," Magazine of Concrete Research, vol. 31, pp. 3-12, 1979.
[36]         Q. Meng and Z. Wang, "Theoretical model of fiber debonding and pull-out in unidirectional hybrid-fiber-reinforced brittle-matrix composites," Journal of Composite Materials, vol. 49, pp. 1739-1751, 2015.
[37]         M. M. Rana, B. Uy, and O. Mirza, "Experimental and numerical study of the bond–slip relationship for post-tensioned composite slabs," Journal of Constructional Steel Research, vol. 114, pp. 362-379, 2015.
[38]         F. Yan and Z. Lin, "Bond behavior of GFRP bar-concrete interface: damage evolution assessment and FE simulation implementations," Composite Structures, vol. 155, pp. 63-76, 2016.
[39]         X. Li, "Finite element modeling of skewed reinforced concrete bridges and the bond-slip relationship between concrete and reinforcement," 2007.
[40]         R. Nayal and H. A. Rasheed, "Tension stiffening model for concrete beams reinforced with steel and FRP bars," Journal of Materials in Civil Engineering, vol. 18, pp. 831-841, 2006.
[41]         C. E.-I. Beton, "CEB-FIP model code 1990: design code," No. 213, vol. 214, 1993.
[42]         L. Kachanov, "Time of the rupture process under creep conditions, Izu," Akad. Nauk SSR Otd. Tech, pp. 26-31, 1958.
[43]         M. Salari, S. Saeb, K. Willam, S. Patchet, and R. Carrasco, "A coupled elastoplastic damage model for geomaterials," Computer methods in applied mechanics and engineering, vol. 193, pp. 2625-2643, 2004.
[44]         R. I. Gilbert and R. F. Warner, "Tension stiffening in reinforced concrete slabs," Journal of the structural division, vol. 104, pp. 1885-1900, 1978.
[45]         D. Ngo and A. Scordelis, "Finite element analysis of reinforced concrete beams," in ACI Journal Proceedings, 1967.
[46]         Hibbitt, Karlsson, and Sorensen, ABAQUS/standard user's Manual vol. 1: Hibbitt, Karlsson & Sorensen, 2001.
[47]         A. Commitee, "C09. ASTM C33-03, Standard Spesification for Concrete Agregates," ed: ASTM International, 2003.
[48]         C. ASTM, "900. 2004. Standard Test Method for Pullout Strength of Hardened Concrete," Annual Book of ASTM Standards.
[49]         B. Larson, "NDT Education Resource Center," ed, 2010.
[50]         E. Garcia-Taengua, J. Marti-Vargas, and P. Serna, "Bond of reinforcing bars to steel fiber reinforced concrete," Construction and Building Materials, vol. 105, pp. 275-284, 2016.
[51]         Y.-W. Chan and S.-H. Chu, "Effect of silica fume on steel fiber bond characteristics in reactive powder concrete," Cement and Concrete Research, vol. 34, pp. 1167-1172, 2004.