LOUISIANA TECH UNIVERSITY College of Engineering and Science

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 3 rd 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 560 Specimen Treated Repair Untreated Repair Undamaged Ave. Strength Increase Factor (SIF) = Treated Repair Untreated Repair Strength Reduction Factor (SRF) = Undamaged Untreated Repair Strength (psi) 400 160 560 = 2. 5 = 3. 5

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, x 3 (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 Top Surface Patch Interface

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.