# Theory of piezoresistivity for strain sensing in carbon fiber reinforced cement under flexure

- 267 Downloads
- 22 Citations

## Abstract

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.

## Keywords

Carbon Fiber Uniaxial Compression Surface Electrical Resistance Surface Resistance Compression Side## Notes

### Acknowledgements

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.

## References

- 1.Chen P-W, Chung DDL (1996) Compos Part B – Eng 27B:11CrossRefGoogle Scholar
- 2.Chung DDL (2002) J Intel Mat Syst Str 13(9):599CrossRefGoogle Scholar
- 3.Wen S, Chung DDL (2003) Adv Cem Res 15(3):119CrossRefGoogle Scholar
- 4.Chung DDL (2002) J Mater Eng Perform 11(2):194CrossRefGoogle Scholar
- 5.Wen S, Chung DDL (2001) Cem Concr Res 31(2):297CrossRefGoogle Scholar
- 6.Wen S, Chung DDL (2000) Cem Concr Res 30(8):1289CrossRefGoogle Scholar
- 7.Fu X, Lu W, Chung DDL (1998) Carbon 36(9):1337CrossRefGoogle Scholar
- 8.Fu X, Chung DDL (1997) Cem Concr Res 27(9):1313CrossRefGoogle Scholar
- 9.Chen P-W, Chung DDL (1993) Smart Mater Struct 2:22CrossRefGoogle Scholar
- 10.Wen S, Chung DDL (2001) Cem Concr Res 31(4):665CrossRefGoogle Scholar
- 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
- 14.Reza F, Batson GB, Yamamuro JA, Lee JS (2003) J Mater Civil Eng 15(5):476CrossRefGoogle 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
- 17.Wen S, Chung DDL (2006) Carbon 44(8):1496CrossRefGoogle Scholar
- 18.Bontea D-M, Chung DDL, Lee GC (2000) Cem Concr Res 30(4):651CrossRefGoogle Scholar
- 19.Fu X, Chung DDL (1996) Cem Concr Res 26(1):15CrossRefGoogle Scholar
- 20.Chung DDL (2003) Mater Sci Eng R 42(1):1CrossRefGoogle Scholar
- 21.Wen S, Chung DDL Cem. Conc r. Res., in pressGoogle Scholar
- 22.Fu X, Chung DDL (1995) Cem Concr Res 25(7):1391CrossRefGoogle Scholar
- 23.Chung DDL (2005) J Mater Civil Eng 17(4):379CrossRefGoogle Scholar
- 24.Wen S, Chung DDL (2006) J Mater Civil Eng 18(3):355CrossRefGoogle Scholar
- 25.Bisschop J, Van Mier JGM (2002) Cem Concr Res 32:279CrossRefGoogle 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