This document discusses smart concrete invented by Professor Deborah Chung. Smart concrete is concrete that can sense its own strain or stress without embedded sensors. It has been modified with admixtures so that changes in electrical resistance allow it to function as a sensor. Two types were studied: one with short carbon fibers and one with carbon nanotubes. Laboratory experiments showed that when molded into squares with electrodes, both types demonstrated piezoresistive properties and were able to detect internal stress and strain, showing potential as sensors for pavement monitoring.

1. Company
LOGO
Smart Concrete
KIRTAN ADHIKARI EDC 2010050
1

2. CONTENT
1. INTRODUCTION
2. INVENTOR AND INVENTION
3. SELF SENSING CONCRETE
4. LABORATORY EXPERIMENT
5. RESULT AND DISCUSSION
2

3. INTRODUCTION
Concrete that is itself a sensor of strain or stress.
The sensing ability is not due to the embedment or attachment of sensors.
 The concrete has been modified through the use of admixtures so that it becomes a sensor
3

4. INTRODUCTION
The sensing ability of smart concrete are based on the change of electrical resistance.
4

5. INVENTOR AND INVENTION
Invented by Professor Deborah Chung in University at Buffalo, State University of New York. (1993)
5

6. Self Sensing Concrete
1.Smart Concrete Produced From Short Carbon Fibres
2.Smart Concrete Produced from CNTs
6

7. Self Sensing Concrete
1.Smart Concrete Produced From Short Carbon Fibres
 Contain short carbon fibres, typically 5 mm in length
Fibre content is 0.2 vol. % of cement
Silica fume content is 15% by weight of cement
Methylcellulose content is 0.4% by weight of cement
7

8. Self sensing concrete
8

9. Self sensing concrete
2. Smart Concrete Produced from CNTs
Carbon nanotubes (CNTs) are seamless tubular structures.
The diameters of CNTs are in the range of 1~20 nm
 The lengths are in the range of 0.2~5 μm.
9

10. Self sensing concrete
10

11.  The mix was prepared with:
 Fibre content is 0.2 vol. % of cement
 Silica fume content is 15% by weight
of cement
 Methylcellulose content is 0.4% by
weight of cement
1. The mix was molded into square
shape with 2 embedded electrode, 1
cm apart.
2. The specimen were cured at standard
temperature of 20 degrees centigrade
and 100 % humidity.
3. Specimens were dried at temperature
of 50 degrees centigrade for 5 days.
EXPERIMENT
11

12. EXPERIMENT
12

13. EXPERIMENT
13

14. RESULT AND DISCUSSION
14

15. CONCLUSION
•The piezoresitive property of carbon nanotubes/CFs enables the composite to detect the stress/stain inside the pavement.
•Experimental results demonstrated that the CNT/cement composite function as excellent stress/strain sensors
15

16. RFERENCES
REFERENCES
[1] B. Demirel, S. Yaziciog˘lu and N. Orhan. (December 2006). Electrical behaviour of carbon fibre-reinforced. Magazine of
Concrete Research, 7.
[2] Chung, D. D. (2006). The Road to Scientific Success. Singapore: World Scientific Pubilishing Co.Pte.Ltd.
[3] Chung, D. D. (1994). Carbon Fiber Composite. Washington: Butterworth-Heinemann.
[4] Chung, D. D. (13 October 1994). Strain sensor based on resistance change accompanying the reversible pull-out of
conducting short fibers in a less conducting matrix. Smart Mater. Strum.
[5] Dr. Xun Yu, Dr. Eil Kwon. (April 2012). Carbon Nanotube Based Self-sensing Concrete for Pavement. Washington:
University of Minnesota Duluth.
16
[1]