Impedance Tests to Assess Corrosion in Reinforce Concrete

Presenter Information

Tim Setala, Minnesota State University, Mankato
Allison Stanek, Minnesota State University, Mankato

Location

CSU 284A

Start Date

5-4-2011 9:00 AM

End Date

5-4-2011 10:30 AM

Student's Major

Mechanical and Civil Engineering

Student's College

Science, Engineering and Technology

Mentor's Name

Farhad Reza

Mentor's Department

Mechanical and Civil Engineering

Mentor's College

Science, Engineering and Technology

Description

The goal of this research was to determine if using impedance tests on concrete cylinders could detect corrosion of steel reinforcing bars (rebars) embedded in the concrete. The impedance tests would provide a convenient alternative nondestructive test method compared to other existing methods. Concrete cylinders with rebar placed inside of them were first constructed. Then salt water baths containing sodium hydroxide and potassium hydroxide that corrodes the rebar inside the concrete were constructed. The concrete cylinders were placed inside of the two baths and connected to a resistor. This was supposed to corrode the rebar inside of the concrete cylinders. Using a voltmeter, the voltage drop was measured each week for 6 weeks and was increasing, which was expected. Also, a reference saturated calomel electrode was used to determine corrosion potential. Then impedance tests were conducted and the data seemed to be inconsistent and hence unreliable as a test method. New concrete cylinders were made with carbon fibers to decrease the electrical resistance and make them easier to monitor. These tests will be compared with the results of the first set of cylinders.