Theory of piezoresistivity for strain sensing in carbon fiber reinforced cement under flexure
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A theory is provided for piezoresistivity in carbon fiber reinforced cement (with and without embedded steel reinforcing bars) under flexure (three-point bending). The phenomenon, which involves the reversible increase of the tension surface electrical resistance and the reversible decrease of the compression surface electrical resistance upon flexure, allows strain sensing. The theory is based on the concept that the piezoresistivity is due to the slight pull-out of crack-bridging fibers during crack opening and the consequent increase in the contact electrical resistivity of the fiber-matrix interface. This work is an extension of prior theory, which concerns the effect of uniaxial loading on the volume resistance. The extension requires modeling the surface resistance and its change under flexure. The theoretical results on the piezoresistivity, both with and without rebar, are in good agreement with prior experimental results. Differences between theoretical and experimental results are probably due to minor damage and rebar debonding during flexure.
KeywordsCarbon Fiber Uniaxial Compression Surface Electrical Resistance Surface Resistance Compression Side
This work was supported in part by the Key Project of National Natural Science Foundation of China under grant No. 50238040. The authors appreciate technical discussion with Dr. Sihai Wen of University at Buffalo, State University of New York.
- 11.Wen S, Chung DDL (2005) ACI Mater J 102(4):244Google Scholar
- 12.Sun M, Mao Q, Li Z (1998) J Wuhan Univ Technol, Mater Sci Ed 13(3):58Google Scholar
- 13.Mao Q, Zhao B, Sheng D, Li Z (1996) J Wuhan Univ Technol 11(3):41Google Scholar
- 15.Wu Y, Bing C, Keru W (2003) Mechanics and Material Engineering for Science and Experiments 172Google Scholar
- 16.Yao W, Chen B, Wu K (2003) J Mater Sci Technol 19(3):239Google Scholar
- 21.Wen S, Chung DDL Cem. Conc r. Res., in pressGoogle Scholar
- 26.Fu X, Chung DDL (1998) ACI Mater J 95(6):725Google Scholar
- 27.Fu X, Chung DDL (1997) Compos Interface 4(4):197Google Scholar