EXPERIMENTAL STUDY ON BOND-SLIP BEHAVIOR BETWEENNSM FRP BARS AND CONCRETE

Abstract

Abstract: Under the pullout specimens strengthened with near-surface mounted (NSM) FRP bars, the bearing capacity process and the failure mode of the specimens are analyzed, and the influence of the parameters about the diameter of FRP bars, bonded length and the type of FRP on bond-slip behavior are studied. The results show that four types of failure modes including debonding failure at the interface between FRP bars and adhesive interface, debonding failure at the interface between concrete and adhesive epoxy, rupture of FRP bars and split of adhesive epoxy are obtained. The bond stress of the specimen with NSM BFRP increases with the bonded length, on the contrary, for the specimen with NSM GFRP bars. Due to the decrease of Poisson ratio of the FRP bars and the shear lag effect, the bond stress of the specimen decreases with increasing the diameter of FRP bars. At the same time, the model of the bond-slip constitutive relationship for the specimen strengthened with NSM-FRP bars is established and the mathematic representation of the characteristic points in the model is proposed based on the analysis and fitting of test results. The comparison between the fitting curve and experimental curve illustrates that the bond-slip constitutive relationship can accurately simulate the bond-slip behavior of concrete strengthened with NSM FRP bars.

Key words: near surface mounted (NSM), FRP bars, bond-slip, constitutive relationship, pullout test

CLC Number:

ZHANG Hai-xia, HE Lu-yuan. EXPERIMENTAL STUDY ON BOND-SLIP BEHAVIOR BETWEENNSM FRP BARS AND CONCRETE[J]. Fiber Reinforced Plastics/Composites, 2016, 0(3): 5-12.

References

[1] Kocaoz S., Samaranayake V.A., Nanni A.. Tensile characterization of glass FRP bars[J].Composites, 2005, 36:127-134.
[2] 郝庆多, 王勃, 欧进萍. 纤维增强塑料筋在土木工程中的应用[J]. 混凝土, 2006(9): 38-40.
[3] De Lorenzis L., J.G. Teng. Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures[J]. Composites: Part B, 2007, 38: 119-143.
[4] De Lorenzis L, Nanni A. Characterization of FRP rods as near-surface mounted reinforcement[J]. Journal of Composites for Construction, 2001, 5(2): 114-121.
[5] Antonio Nanni. North American design guidelines for concrete reinforcement and strengthening using FRP: principles, applications, and unresolved issues[J]. Construction and Building Materials, 2005, 17: 439-446.
[6] 郝庆多, 王言磊, 侯吉林, 等. GFRP带肋筋粘结性能试验研究[J]. 工程力学, 2008, 25(10): 158-165.
[7] 郝庆多, 王言磊, 欧进萍. 拉拔条件下GFRP筋与混凝土粘结强度试验研究[J]. 建筑结构学报, 2008, 29(1): 103-111.
[8] Sharaky IA, Torres L, Baena M, et al. Effect of different material and construction details on the bond behaviour of NSM FRP bars in concrete[J]. Construction and Building Material, 2013, 38:890-902.
[9] Bilotta A, Ceroni F, Di Ludovico M, et al. Bond efficiency of EBR and NSM FRP systems for strengthening concrete members[J]. Journal of Composite for Construction, 2011,15(7):757-772.
[10] Seracino R, Jones N, Ali M, et al. Bond strength of near-surface-mounted CFRP strip-to-concrete joints[J]. Journal of Composite for Construction, 2007, 11(4):401-409.
[11] Shehab M Soliman, Ehab Salakawy, Brahim Benmokrane. Bond performance of near-surface-mounted FRP bars[J]. Journal of Composites for Construction, 2011,15(1): 103-111.
[12] Sharaky IA, Torres L, Baena M. An experimental study of different factors affecting the bond of FRP bars in concrete[J]. Composite Structures, 2013, 99:350-365.
[13] Dongkeun Lee, Lijuan Chen, Jason Yan-Gee Hui. Bond characteristics of various NSM FRP reinforcements in concrete[J]. Journal of Composites for Construction, 2013,17(1):117-129.
[14] Lin Xiaoshan, Zhang Y.X.. Bond-slip behavior of FRP-reinforced concrete beams[J]. Construction and Building Materials, 2013, 44:110-117.
[15] Mario R.F. Coelho, Jose M. Sena-Cruz, Luis A.C. Neves. A review on the bond behavior of FRP NSM systems in concrete[J]. Construction and Building Materials, 2015, 93: 1157-1169.