Transcript Concrete Crack Repair - Louisiana Tech University

LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Electrokinetic Hardening
of Concrete Structures
Dr. Henry E. Cardenas, Ph.D.
Jack T. Painter Professor of Civil Engineering
Associate Professor of Mechanical and Nanosystems Engineering
Director, Applied Electrokinetics Laboratory
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Crack Repair of Concrete
Portion of structure
removed
Concrete structure
Problematic crack
Patch material filling
void in structure
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Crack Repair Strength Test
7
14“
Repaired specimen
loaded in 3rd point
bending.
4
Bend test
specimen with
center crack.
Crack cut open
and replaced by
repair patch.
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Electrokinetic Nanoparticle Repair
Power Supply
V
I
Negative
Electrode
Positive
Electrode
Repair
Electrode
Side View
Repair
Interface
End View
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Treatment Impact on Interface Strength
Fracture
Strength
Load, P (lb)
(psi)
1
2800
408
2
2700
394
3
2650
387
1
1000
146
2
1200
175
3
1150
168
1
3820
557
2
3860
563
3
3840
Specimen
Treated
Repair
Untreated
Repair
Undamaged
Strength Increase Factor (SIF)
Ave.
Strength
(psi)
400
160
560
560
=
Treated Repair = 2.5
Untreated Repair
Strength Reduction Factor (SRF) =
Undamaged
= 3.5
Untreated Repair
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Treatment Enhancement
• Build up nanoparticles right at patch interface
• Increase bond strength between patch material and
original concrete structure
Repair Electrode
Top Surface
Patch Interface
This worked very Poorly!
•Additional Stress, x3
(next to electrode)
•Interface SRF ~ 3.5
•Top surface has the
highest stress
Lots of room to Optimize: Porosity reduction at patch may enhance strength by factor of 9
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Treatment Optimization
• Place treatment electrode off of patch interface
• Place the electrode away from top surface
• Optimize electrode location
Repair Electrode
t patch
X
Top Surface
Patch Interface
d structure
Y
t patch
d structure
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Optimum Electrode Placement
Top Surface
3.0
2.85
Patch Interface
2.7
Unsatisfactory
electrode placement
region
y
Center of
Repair Patch
Satisfactory region
0.
0
○
0.0
0.48
0.85 1.0
x
LOUISIANA TECH UNIVERSITY
College of Engineering and Science
Acknowledgements
Entergy, Charles Turk
Daniela Maindardi,
Jinko Kanno,
James Philips,
Israel Popoola,
Kunal Kupwade-Patil,
Mark Castay,
Joshua Alexander,
Paul Femmer.