Abstract
Tensile tests on fabric-reinforced cementitious matrix (FRCM) coupons are used to evaluate the tensile mechanical properties of the composite. Bond tests, typically single-lap shear tests, are used to characterize the interfacial properties between the FRCM composite and the substrate and to identify the interface at which debonding takes place. Some FRCM composites exhibit debonding at the fiber–matrix interface, which is characterized by a cohesive material law (CML) that can be obtained from bond tests. The authors have shown that for these composites, the CML can be fed into an analytical model to predict the results of tensile tests. In this paper, the same model is used to highlight some critical aspects of the clevis-grip tensile test. In particular, it will be shown that the length of the gripping devices, the length of the specimen, and the gauge length adopted to measure the deformation of the specimen have a strong influence on the results of the tensile tests. In addition, an analogy between the clevis-grip tensile test and single-lap shear test will point out that the tensile test is a bond test and can be used to determine the bond capacity rather than the tensile properties, which will be proven to be non-uniquely defined by this test.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
This research was carried out in the framework of the DPC-ReLUIS 2019–2021 project (WP 14) funded by the Italian Department of Civil Protection. Dr. Carloni would like to acknowledge the start-up fund provided by Case Western Reserve University, which was partially used to support this research, and grant RES515729 from National Center for Transportation (Washington State University).
Notation
The following symbols are used in this paper:
- A
- parameter of the CML;
- Af
- area of the cross section of the longitudinal fibers in a FRCM plane element;
- Am
- area of the cross section of the matrix in a FRCM plane element;
- bf
- width of the textile in a tensile specimen;
- bm
- width of the matrix in a tensile specimen;
- b1
- width of the matrix in a single-lap shear test;
- dmin
- distance between two consecutive cracks at the end of the cracking process of a tensile specimen;
- EFRCM
- cracked elastic modulus of the FRCM computed according to AC434 (ICC 2013);
- Ef
- elastic modulus of the fibers;
- Em
- elastic modulus of the matrix;
- F
- tensile force applied to a tensile test specimen;
- f
- function defining the distribution of the load transferred by the plates to the matrix at the ends of a tensile specimen;
- FJ
- tensile force corresponding to Point J of the load response, J ≡ A, C, E, or G;
- Fmax
- tensile capacity of a tensile test specimen;
- ff
- tensile strength of the fibers;
- ffe
- effective stress of the FRCM, according to ACI 549 (ACI 2020);
- ffu
- tensile strength of the FRCM, according to ACI 549 (ACI 2020);
- ft
- tensile strength of the matrix;
- g
- global slip, that is, slip at the loaded end in a single-lap shear test;
- Gf
- fracture energy of the fiber–matrix interface;
- fracture energy of the matrix;
- j
- natural number;
- ℓ
- bonded length in single-lap shear tests;
- Lc
- critical length, that is, twice the length needed to transfer the matrix-cracking force ftAm;
- Lg
- gripped length of a tensile specimen, that is, length of each portion of the plate glued to the specimen at its ends;
- Lm
- gauge length in the central portion of a tensile specimen;
- Lt
- free length of a tensile specimen, that is, length of the central part of the specimen between the plates;
- m
- generic value of Lm;
- n
- number of textile layers in a FRCM plane element;
- P
- tensile force applied to the textile in a single-lap or pullout test;
- Pmax
- maximum load transferable at the fiber–matrix interface in a single-lap or pullout test;
- pf
- width of the fiber–matrix interfacial surface, that is, contact perimeter;
- q
- tangential load per unit length transferred by the plates to the matrix at the two ends of a tensile specimen along the gripped length;
- q0
- parameter defining the amplitude of the load transferred by the plates to the matrix at the ends of a tensile specimen;
- s
- slip;
- sE
- modulus of the fiber–matrix slip at the ends of a tensile specimen;
- sF
- slip at the free end in a single-lap shear test;
- sf
- slip at the beginning of the friction branch in the CML, that is, τ = τf for s ≥ sf;
- smax
- maximum slip, that is, slip at the end of the plates, at the maximum load of a tensile specimen;
- tm
- thickness of a tensile specimen;
- tf
- equivalent thickness of the textile;
- uf
- longitudinal displacement of the fibers;
- um
- longitudinal displacement of the matrix;
- w
- crack opening;
- wch
- characteristic crack opening defined as ;
- wf
- critical crack opening corresponding to zero stress transferred between the crack faces;
- wL
- opening of the last formed crack during the cracking process of a tensile specimen;
- y
- reference axis placed in the center line of the midplane of a tensile specimen and longitudinal reference axis in single-lap shear tests;
- α
- parameter of the CML;
- ΔLm
- elongation of the central portion of length Lm of a clevis-grip tensile specimen, evaluated on the matrix surface;
- ΔLt
- elongation of a clevis-grip tensile specimen, evaluated as the relative displacement of the plates of a tensile specimen;
- ɛ
- strain;
- ɛ06
- global strain ɛav or global strain of the central part corresponding to 0.6Fmax;
- ɛ09
- global strain ɛav or global strain of the central part corresponding to 0.9Fmax;
- ɛav
- global strain of the tensile specimen, evaluated as ɛav = ΔLt/Lt;
- ɛav,max
- deformation capacity of a tensile specimen in terms of ɛav, that is, strain ɛav corresponding to the tensile capacity Fmax;
- ɛf
- local strain of the fibers in a tensile or single-lap specimen;
- ɛfe
- effective strain of the FRCM, according to ACI 549 (ACI 2020);
- ɛft
- failure strain of the fibers;
- ɛfu
- ultimate strain of the FRCM, according to ACI 549 (ACI 2020);
- ɛm
- local strain of the matrix in a tensile or single-lap specimen;
- global strain of the central part of a tensile specimen, evaluated as ;
- deformation capacity of a tensile specimen in terms of , that is, strain corresponding to the tensile capacity Fmax;
- ɛt
- cracking strain of the matrix;
- σf
- axial stress in the fibers;
- σintercept
- fiber stress corresponding to the intercept of the secant line used to compute EFRCM with the vertical axis of the F–ɛav response;
- σm
- axial stress in the matrix;
- τ
- shear stress at the fiber–matrix interface;
- τf
- friction shear stress at the fiber–matrix interface; and
- τs
- shear stress at the matrix-substrate interface in a single-lap shear test.
References
ACI (American Concrete Institute). 2020. Guide to design and construction of externally bonded fabric-reinforced cementitious matrix (FRCM) and steel-reinforced grout (SRG) systems for repair and strengthening masonry structures. ACI Committee 549. ACI 549.6R-20. Farmington Hill, MI: ACI.
Alecci, V., S. Barducci, M. D. Stefano, S. Galassi, R. Luciano, L. Rovero, and G. Stipo. 2021. “Reliability of different test setups and influence of mortar mixture on the fabric-reinforced cementitious matrix-to-brick bond response.” J. Test. Eval. 49 (6): 20200656.
Arboleda, D. 2014. “Fabric reinforced cementitious matrix (FRCM) composites for infrastructure strengthening and rehabilitation: characterization methods.” Ph.D. thesis, Dept. of Civil and Architectural Engineering, Univ. of Miami.
Arboleda, D., F. G. Carozzi, A. Nanni, and C. Poggi. 2016. “Testing procedures for the uniaxial tensile characterization of fabric-reinforced cementitious matrix composites.” J. Compos. Constr. 20 (3): 04015063. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000626.
Askouni, P. D., and C. Papanicolaou. 2018. “Comparison of double-Lap/double-prism and single-Lap/single-prism shear tests for the TRM-to-masonry bond assessment.” In Strain-Hardening cement-based composites, RILEM Bookseries, edited by V. Mechtcherine, V. Slowik, and P. Kabele, 527–534. Dordrecht, Netherlands: Springer.
Askouni, P. D., and C. Papanicolaou. 2019. “Textile reinforced mortar-to-masonry bond: Experimental investigation of bond-critical parameters.” Constr. Build. Mater. 207: 535–547. https://doi.org/10.1016/j.conbuildmat.2019.02.102.
Askouni, P. D., and C. Papanicolaou. 2020. “Role of mortar joints in textile reinforced mortar-to-masonry bond.” J. Compos. Constr. 24 (6): 04020069.
Bakis, C. E., C. Bank Lawrence, V. L. Brown, E. Cosenza, J. F. Davalos, J. J. Lesko, A. Machida, S. H. Rizkalla, and T. C. Triantafillou. 2002. “Fiber-reinforced polymer composites for construction—State-of-the-art review.” J. Compos. Constr. 6 (2): 73–87. https://doi.org/10.1061/(ASCE)1090-0268(2002)6:2(73).
Bazant, Z. P., and J. Planas. 2019. Fracture and size effect in concrete and other quasibrittle materials. London: Routledge.
Belliazzi, S., G. Ramaglia, G. P. Lignola, and A. Prota. 2021. “Out-of-plane retrofit of masonry with fiber-reinforced polymer and fiber-reinforced cementitious matrix systems: Normalized interaction diagrams and effects on mechanisms activation.” J. Compos. Constr. Eng. 25 (1): 04020081.
Bilotta, A., and G. P. Lignola. 2021. “Effect of fiber-to-matrix bond on the performance of inorganic matrix composites.” Compos. Struct. 265: 113655. https://doi.org/10.1016/j.compstruct.2021.113655.
Brückner, A., R. Ortlepp, and M. Curbach. 2006. “Textile reinforced concrete for strengthening in bending and shear.” Mater. Struct. 39 (8): 741–748. https://doi.org/10.1617/s11527-005-9027-2.
Calabrese, A. S., P. Colombi, and T. D’Antino. 2019. “Analytical solution of the bond behavior of FRCM composites using a rigid-softening cohesive material law.” Composites, Part B. 174: 107051. https://doi.org/10.1016/j.compositesb.2019.107051.
Campanini, D. 2018. “Comparison between direct tensile and single lap shear for FRCM/SRG composites.” Master thesis Alma Mater Studiorum - Università di Bologna.
Carloni, C., M. Santandrea, and I. A. O. Imohamed. 2017. “Determination of the interfacial properties of SRP strips bonded to concrete and comparison between single-lap and notched beam tests.” Eng. Fract. Mech. 186: 80–104. https://doi.org/10.1016/j.engfracmech.2017.09.020.
Carozzi, F. G., G. Milani, and C. Poggi. 2014. “Mechanical properties and numerical modeling of fabric reinforced cementitious matrix (FRCM) systems for strengthening of masonry structures.” Compos. Struct. 107: 711–725. https://doi.org/10.1016/j.compstruct.2013.08.026.
Carozzi, F. G., and C. Poggi. 2015. “Mechanical properties and debonding strength of fabric reinforced cementitious matrix (FRCM) systems for masonry strengthening.” Composites, Part B 70: 215–230. https://doi.org/10.1016/j.compositesb.2014.10.056.
Chen, J. F., and J. G. Teng. 2001. “Anchorage strength models for FRP and steel plates bonded to concrete.” J. Struct. Eng. 127 (7): 784–791. https://doi.org/10.1061/(ASCE)0733-9445(2001)127:7(784).
CNR (National Research Council). 2020. Guide for the design and construction of externally bonded fibre reinforced inorganic matrix systems for strengthening existing structures. CNR-DT 215/2018. Rome: CNR.
Consiglio Superiore dei Lavori Pubblici. 2018. Linea Guida per la identificazione, la qualificazione ed il controllo di accettazione di compositi fibrorinforzati a matrice inorganica (FRCM) da utilizzarsi per il consolidamento strutturale di costruzioni esistenti. D. Cons. Sup. LL.PP. 08/01/2019, n. 12.
Contamine, R., A. Si Larbi, and P. Hamelin. 2011. “Contribution to direct tensile testing of textile reinforced concrete (TRC) composites.” Mater. Sci. Eng. A 528 (29–30): 8589–8598. https://doi.org/10.1016/j.msea.2011.08.009.
D’Antino, T., F. G. Carozzi, P. Colombi, and C. Poggi. 2017. “A new pull-out test to study the bond behavior of fiber reinforced cementitious composites.” Key Eng. Mater. 747: 258–265.
D’Antino, T., F. Focacci, L. H. Sneed, and C. Carloni. 2020a. “Relationship between the effective strain of PBO FRCM-strengthened RC beams and the debonding strain of direct shear tests.” Eng. Struct. 216: 110631. https://doi.org/10.1016/j.engstruct.2020.110631.
D’Antino, T., F. Focacci, L. H. Sneed, and C. Pellegrino. 2020b. “Shear strength model for RC beams with U-wrapped FRCM composites.” J. Compos. Constr. 24 (1): 04019057.
de Felice, G., T. D’Antino, S. De Santis, P. Meriggi, and F. Roscini. 2020. “Lessons learned on the tensile and bond behavior of fabric reinforced cementitious matrix (FRCM) composites.” Front. Built Environ. 6: 5.
de Felice, G., S. D. Santis, and P. Meriggi. 2021. “An overview of the tensile and bond behavior of fabric reinforced cementitious matrix (FRCM) composites.” Spec. Publ. 345: 207–220.
Donnini, J., V. Corinaldesi, and A. Nanni. 2016. “Mechanical properties of FRCM using carbon fabrics with different coating treatments.” Composites, Part B 88: 220–228. https://doi.org/10.1016/j.compositesb.2015.11.012.
Fazzi, E., G. Misseri, L. Rovero, and G. Stipo. 2022. “Finite difference model for the bond behaviour of polyparaphenylene benzobisoxazole (PBO) fibre-reinforced composite system for retrofitting masonry.” Key Eng. Mater. 916: 425–432. https://doi.org/10.4028/p-6848f4.
Ferretti, F., and C. Mazzotti. 2021. “FRCM/SRG strengthened masonry in diagonal compression: Experimental results and analytical approach proposal.” Constr. Build. Mater. 283: 122766. https://doi.org/10.1016/j.conbuildmat.2021.122766.
Focacci, F., T. D’Antino, and C. Carloni. 2020. “The role of the fiber–matrix interfacial properties on the tensile behavior of FRCM coupons.” Constr. Build. Mater. 265: 120263. https://doi.org/10.1016/j.conbuildmat.2020.120263.
Focacci, F., T. D’Antino, and C. Carloni. 2022. “Relationship between results of tensile test of FRCM composites and the fiber-matrix bond properties.” Key Eng. Mater. 916: 417–424. https://doi.org/10.4028/p-5rwvlo.
Focacci, F., T. D’Antino, C. Carloni, L. H. Sneed, and C. Pellegrino. 2017. “An indirect method to calibrate the interfacial cohesive material law for FRCM-concrete joints.” Mater. Des. 128: 206–217. https://doi.org/10.1016/j.matdes.2017.04.038.
Grande, E., and G. Milani. 2021a. “Procedure for the numerical characterization of the local bond behavior of FRCM.” Compos. Struct. 258: 113404. https://doi.org/10.1016/j.compstruct.2020.113404.
Grande, E., and G. Milani. 2021b. “Modeling of FRCM strengthening systems externally applied on curved masonry substrates.” Eng. Struct. 233: 111895. https://doi.org/10.1016/j.engstruct.2021.111895.
Grande, E., G. Milani, and M. Imbimbo. 2020. “Theoretical model for the study of the tensile behavior of FRCM reinforcements.” Constr. Build. Mater. 236: 117617. https://doi.org/10.1016/j.conbuildmat.2019.117617.
Hartig, J., U. Häußler-Combe, and K. Schicktanz. 2008. “Influence of bond properties on the tensile behaviour of textile reinforced concrete.” Cem. Concr. Compos. 30 (10): 898–906. https://doi.org/10.1016/j.cemconcomp.2008.08.004.
Hartig, J., F. Jesse, K. Schicktanz, and U. Häußler-Combe. 2012. “Influence of experimental setups on the apparent uniaxial tensile load-bearing capacity of textile reinforced concrete specimens.” Mater. Struct. 45 (3): 433–446. https://doi.org/10.1617/s11527-011-9775-0.
Häußler-Combe, U., and J. Hartig. 2007. “Bond and failure mechanisms of textile reinforced concrete (TRC) under uniaxial tensile loading.” Cem. Concr. Compos. 29 (4): 279–289. https://doi.org/10.1016/j.cemconcomp.2006.12.012.
ICC (International Code Council). 2013. Acceptance criteria for masonry and concrete strengthening using fiber-reinforced cementitious matrix (FRCM) composite systems. AC434. ICC Evaluation Service. Washington, DC: ICC.
Lignola, G. P., A. Bilotta, and F. Ceroni. 2019. “Assessment of the effect of FRCM materials on the behaviour of masonry walls by means of FE models.” Eng. Struct. 184: 145–157. https://doi.org/10.1016/j.engstruct.2019.01.035.
Meriggi, P., S. De Santis, S. Fares, and G. de Felice. 2021. “Design of the shear strengthening of masonry walls with fabric reinforced cementitious matrix.” Constr. Build. Mater. 279: 122452. https://doi.org/10.1016/j.conbuildmat.2021.122452.
Murgo, F. S., F. Ferretti, and C. Mazzotti. 2021. “A discrete-cracking numerical model for the in-plane behavior of FRCM strengthened masonry panels.” Bull. Earthquake Eng. 19 (11): 4471–4502. https://doi.org/10.1007/s10518-021-01129-6.
Ombres, L. 2012. “Debonding analysis of reinforced concrete beams strengthened with fibre reinforced cementitious mortar.” Eng. Fract. Mech. 81: 94–109.
Papanicolaou, C. G., T. C. Triantafillou, M. Papathanasiou, and K. Karlos. 2008. “Textile reinforced mortar (TRM) versus FRP as strengthening material of URM walls: Out-of-plane cyclic loading.” Mater. Struct. 41 (1): 143–157. https://doi.org/10.1617/s11527-007-9226-0.
Reinhardt, H. W., H. A. W. Cornelissen, and D. A. Hordijk. 1986. “Tensile tests and failure analysis of concrete.” J. Struct. Eng. 112 (11): 2462–2477. https://doi.org/10.1061/(ASCE)0733-9445(1986)112:11(2462).
Rovero, L., S. Galassi, and G. Misseri. 2020. “Experimental and analytical investigation of bond behavior in glass fiber-reinforced composites based on gypsum and cement matrices.” Composites, Part B 194: 108051. https://doi.org/10.1016/j.compositesb.2020.108051.
Santandrea, M., F. Focacci, C. Mazzotti, F. Ubertini, and C. Carloni. 2020. “Determination of the interfacial cohesive material law for SRG composites bonded to a masonry substrate.” Eng. Fail. Anal. 111: 104322. https://doi.org/10.1016/j.engfailanal.2019.104322.
Younis, A., U. Ebead, and K. C. Shrestha. 2017. “Different FRCM systems for shear-strengthening of reinforced concrete beams.” Constr. Build. Mater. 153: 514–526. https://doi.org/10.1016/j.conbuildmat.2017.07.132.
Yuan, H., J. G. Teng, R. Seracino, Z. S. Wu, and J. Yao. 2004. “Full-range behavior of FRP-to-concrete bonded joints.” Eng. Struct. 26 (5): 553–565. https://doi.org/10.1016/j.engstruct.2003.11.006.
Information & Authors
Information
Published In
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Oct 7, 2021
Accepted: Mar 17, 2022
Published online: Jun 14, 2022
Published in print: Aug 1, 2022
Discussion open until: Nov 14, 2022
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
- Anna Castellano, Aguinaldo Fraddosio, Daniel V. Oliveira, Mario D. Piccioni, Eleonora Ricci, Elio Sacco, An effective numerical modelling strategy for FRCM strengthened curved masonry structures, Engineering Structures, 10.1016/j.engstruct.2022.115116, 274, (115116), (2023).
- Chenglin Wan, Jiyang Wang, Shubin Wang, Xiaohua Ji, Yu Peng, Hongmei Zhang, Tensile Behavior of Basalt Textile Reinforced Concrete: Effect of Test Setups and Textile Ratios, Materials, 10.3390/ma15248975, 15, 24, (8975), (2022).
- Dario De Domenico, Natale Maugeri, Paolo Longo, Giuseppe Ricciardi, Giuseppe Gullì, Luigi Calabrese, Clevis-Grip Tensile Tests on Basalt, Carbon and Steel FRCM Systems Realized with Customized Cement-Based Matrices, Journal of Composites Science, 10.3390/jcs6090275, 6, 9, (275), (2022).
- Maria Teresa Cristofaro, Angelo D’Ambrisi, Francesco Focacci, Marco Tanganelli, Mario De Stefano, Beam tests for the determination of the interfacial properties of FRCM composites, Case Studies in Construction Materials, 10.1016/j.cscm.2022.e01485, 17, (e01485), (2022).