Electrically Conductive Concrete - University of...

Electrically

Conductive Concrete

Michelle HoUniversity of Houston

Cullen College of Engineering

smho@uh.edu

Electrically Conductive Concrete

• Definition

Chopped Carbon Fiber

(CCF)

Resistive heatingResistive heating

Problem

• Ice and snow build-up

driving hazards

traffic and time traffic and time

delays

History and Past Projects

• Sodium chloride

Pros Inexpensive

Simple application

ConsCons Ruins groundwater and

vegetation

Corrosion of reinforcing bars

Concrete surface damage

History and Past Projects (cont’d)

• Heating cables Pros

Effective deicing

Cons Traffic disturbances

High energy costs High energy costs

• Heating Pipes Pros

Effective deicing

Cons Leaks lead to almost

impossible maintenance

Complex and costly

Purpose

– Solving the de-icing problem

– Achieving and maintaining cost efficiency– Achieving and maintaining cost efficiency

– Reduce damage and maintenance to concrete

and environment

Scope

• Investigation into conductive concrete’s:

– Resistive properties

– Heating properties– Heating properties

Design of System

Design of System (cont’d)

• Two types of electrodes

– Zinc Perforated Metal Sheets (a)

– Aluminum Mesh (b)

(a) (b)

Procedures

• Resistivity Testing

Two point probe method

Input: voltage

Output: current readings

V = I * R

Slope: resistance

• Heating Testing

– Heating and Cooling

– Temperature and current

readingsSample connected to a power

supply

Resistivity ResultsAverage Resistance (Ohms) vs. % CCF by Mass of Cement

250

300

350

400

450

500

Re

sis

tan

ce

(Ω

)

0

50

100

150

200

250

0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80

% CCF by Mass of Cement

Re

sis

tan

ce

(

Zinc Mesh

Resistance (Ohms) vs. % CCF by Mass of Cement

300

350

400

450

500

Resis

tan

ce (Ω

)Resistivity Results (cont’d)

0

50

100

150

200

250

0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80

% CCF by Mass Cement

Resis

tan

ce (

Zinc Mesh

Problem

• Due to the unexpected high amount of

resistance encountered when the sample

was frozen, which did not occur when the was frozen, which did not occur when the

sample was at room temperature, a heating

and cooling test were done to investigate

the relationship between temperature and

resistance.

Cooling Results

2000

2500

3000

Re

sis

tan

ce

(Ω

)

Cooling 1% CCF

Cooling 1.67% CCF

0

500

1000

1500

-10 -5 0 5 10 15 20 25

Temperature (°C)

Re

sis

tan

ce

(

Heating Results

1200

1400

1600

1800

2000

Re

sis

tan

ce

(Ω

)

1% CCF Heating

1.67% CCF Heating

0

200

400

600

800

1000

-15 -10 -5 0 5 10 15 20

Temperature (°C)

Re

sis

tan

ce

(

Example of mortar blocks in a freezer

Discussion

• Resistive Testing

Correlation

Inversely proportional relationship between Inversely proportional relationship between

resistance and percentage of CCF

Increase in CCF triggers a decrease in resistance and

increase in current

Discussion (cont’d)

• Heating Testing

Problem

Resistance too high (quadrupled)Resistance too high (quadrupled)

Only .05 A and 1 W power output with 20 V input

Correlation: Inversely proportional relationship

between temperature and resistance

Future Work

• Design better concrete system

to solve resistance problem in

the heating test

• Various course aggregates • Various course aggregates

and admixtures

• Sonication and compaction

– eliminate entrapped air

bubbles in non-solidified

concrete mixturesFly Ash

Acknowledgements

• Dr. Mo – REU advisor

• Dr. Gangbing Song – Faculty Mentor

• Christiana Chang – Masters Mentor

• The research study described herein was • The research study described herein was sponsored by the National Science Foundation under the Award No. EEC-0649163. The opinions expressed in this study are those of the authors and do not necessarily reflect the views of the sponsor.

References

• http://www.newsgd.com/news/picstories/content/images/attachement/jpg/site26/20080204/0010dc53fa040910b7cd05.jpg

• http://www.fhwa.dot.gov/PAVEMENT/recycling/fach01.cfm

• http://www.tohotenax.com/tenax/en/products/images/photo_chopped.jpg

• http://img.directindustry.com/images_di/photo-g/chopped-carbon-fiber-363314.jpgfiber-363314.jpg

• http://www.allwarm.com/images/installdway1.jpeg

• http://www.instablogsimages.com/images/2008/01/01/roadenergysystems_6648.jpg

• http://www.dailycommercialnews.com/images/archivesid/32825/400.jpg

• Christiana Chang (2009). “Development of Self-Heating Concrete Utilizing Carbon Nanofiber Heating Elements.”

References (Cont’d)

• Cress, M. D. 1995. “Heated bridge deck construction and operation in Lincoln, Nebraska.” IABSE Symp., San Francisco, 449–454.

• Roosevelt, D. S. 2004. “A bridge deck anti-icing system in Virginia: Lessons learned from a pilot study,” Final Rep. No. VTRC 04-R26, Virginia Transportation Research Council, Charlottesville, Va.

• Sun Mingquing, Li Zhuoqiu, and Mao Quizhao. 1997. “Study on the Electrothermal Property of CFRC[J].” Journal of Wuhan University of Technology. V 19. Issue 2. 72-74.

• Tang, Zuquan. June 2006. “Influential Factors on Deicing Performance of electrically Conductive Concrete Pavement.” Journal of Wuhan University of Technology – Mater. Sci. Ed. Volume 21. No 2.

• Tang, Zuquan, Li Zhouqiu, Hou Zuofu, et al. 2002. “Influence of Setting of Electrical Conductive concrete Heating Layer on Effectiveness of Deicing[J].” Journal fo Wuhan University of Technology – Mater. Sci. Ed. Volume 17. Issue 3. 41-45.

• Tuan Christopher Y. March 2008. “Roca Spur Bridge: The Implementation of an Innovative Deicing Technology.” • Tuan Christopher Y. March 2008. “Roca Spur Bridge: The Implementation of an Innovative Deicing Technology.” Journal of Cold Regions Engineering (U. of Nebraska). Volume 22 Issue 1, 1-15.

• Tuan, Christopher Y. 2004. “Electrical Resistance Heating of Conductive concrete Containing Steel Fibers and Shavings.” ACI Materials Journal, V. 101, No. 1. 65-71.

• Williams, D., Williams, N., and Cao, Y. (2000). “Road salt contamination of ground water in major metropolitan area and development of a biological index to monitor its impact.” Water Research, 1 (34), 127-138.

• Yehia, Sherif and Tuan, Christopher Y. 1998. “Bridge Deck Deicing.” Transportation Conference Proceedings, Department of Civil Engineering, University of Neraska-Lincoln. 51-57.

• Yehia, S. A., Tuan, C, Y., Ferdon, D., and Chen B. 2000. “Conductive Concret Overlay for Bridge Deck Deicing: Mixture Proportioning Optimization, and Properties.” ACI Materials Journal. V. 97, No. 2. 172-181.