1. Initial Condition Assessment: Concrete Traffic
John Lawler & Joshua Freedland
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2. Intro to WJE
Interdisciplinary engineering, architecture, and materials science firm; Founded in 1956
Specialized in the evaluation and repair of existing structures

3. Background: Construction of Concrete Traffic
1967 Cadillac DeVille
Cage of rebar and welded wire fabric (mesh)
Plywood forms supported with steel angles
Ready-mix concrete
Cast in January 8, 1970
Concrete likely needed accelerator - Typical in Chicago at that time: calcium chloride
0-60: 5.7 sec.
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4. Background: Distress Mechanisms in Concrete Structures
Corrosion
Carbonation
Chlorides
Cyclic Freezing and Thawing/Scaling
Structural Loading
Volumetric Changes
Drying Shrinkage
Thermal Contraction

5. Initial Assessment of Concrete Traffic
Visual Survey
GPR (Ground Penetrating Radar)
Concrete Sample
Electrical Continuity
BETTER PHOTO FROM NATE?
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6. Findings: Visual Survey
Overall concrete condition
Honeycomb
Previous repairs (Two types) – at least one is original
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7. Findings: Visual Survey
Cracking – at bottom and at corners
Front Left
Rear Right

8. Findings: Visual Survey
Cracking – at corners
Front Right

9. Findings: Visual Survey
Cracking - Vertical & Structural and Shrinkage
Front
Right

10. Findings: Visual Survey
Cracking - Vertical & Structural and Shrinkage

11. Findings: Visual Survey
Cracking - In repairs

12. Findings: Visual Survey
Corrosion of Angles

13. Findings: Visual Survey
Corrosion of Angles

14. Findings: Visual Survey
Concrete Distressed Caused by Corrosion of Angles

15. Findings: Visual Survey
Freeze-thaw/Scaling distress

16. Findings: Visual Survey
Organic Growth

17. Findings: Visual Survey
Iron Staining
Misc. sealant

18. Findings: Visual Survey
Underside condition
Support of “X-frame”

19. Findings: GPR
Cracks do not line up with reinforcing cracks not corrosion
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20. Findings: GPR Right Side Left Side Middle of face
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21. Findings: GPR Deflection in roofline 5 in. Front of roof
Middle of roof
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22. Findings: GPR Surface Concrete thickness Cover over steel
Top (hood, roof, trunk)
6 to 8 in.
3-1/2 to 6 in.
Sides (right and left)
4 to 8 in.
1-1/4 to 5 in.
Back
6-1/2 in.
3-1/4 to 4-1/2 in.
Front
7 to 8 in.
0 to 4 in.

23. Reinforcing Cover Depth (in.)
Findings: GPR
Element
Reinforcing Cover Depth (in.)
Depth of Car
(in.)
Min
Max
Average
Top of Sculpture - Hood
4.0
6.3
5.5
6.2
8.6
Top of Sculpture - Top
3.5
5.6
4.8
5.9
6.6
Top of Sculpture - Trunk
4.3
5.7
7.1
Right Side of Sculpture
1.3
3.2
2.1
4.2
Left Side of Sculpture
1.7
4.9
2.7
5.4
8.0
Back of Sculpture
3.3
4.6
4.1
6.8
Front of Sculpture
1.2
2.3
6.9

24. Findings: Concrete Sample
Sample from over angle from front of car
Freeze-thaw damage – concrete not air entrained
Chloride content = 0.043% chloride by mass of sample– acid soluble
Threshold is approx ppm
Carbonation = ~1/8 in.
Cause of corrosion likely admixed chloride

25. Significance of Observed Distress for Durability of Concrete Traffic
Corrosion of angles
Cracking at corners
Corrosion of embedded steel (?)
Freeze-thaw/scaling
Vertical cracking at rear support
Cracking - in original repairs & vertical cracks
Organic growth (algae)
Isolated other stains

26. Repair Options: Corrosion of Angles
Cathodic Protection
Impressed Current (Active)
Galvanic (Passive)
Chloride Extraction
Remove Angle (?!)
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27. Repair Options: Other Items
Overall concrete distress
Water-repellant sealer (silane) – keep dry
Cracking
Crack Injection
Crack Filling
Organic Growth
Cleaners
IMAGE FOR CLEANING?
IMAGE FOR CRACK INJECTION?
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28. Next Steps for Investigation
Condition Survey
Crack widths
Petrographic Analysis
Chloride Testing
Half-cell potential survey
Steel Section Loss
Repair Development
Cleaning studies
JDF-do we want to try injection for cracks?
Also some isolated iron staining
Isolated sealant goo?
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29. Thank you

30. New Site on CAMPUS
The site must be prepared with a custom made structural support frame and waterproofed pad, designed in collaboration with structural engineers and under the conservators recommendations.
The site must also fulfill the following criteria:
It should also not be under or too close to a tree with falling leaves.
It should be in an area with reasonably dense pedestrian traffic and good lighting to protect it from vandalism.
It should be where a real car could be, but it should be protected from collision with moving cars and regular street maintenance such as salting, street cleaning and snow ploughing.
When it returns to campus we don’t want it to be moved again, it needs to be on a specially made waterproof pad so the site must be considered permaent. There should also be a hidden Structural support frame will be made for the car itself rather than the to support the concrete. The considerations for the site have also been specified by Christian Schieidemann, not to allow for further increased biological growth, to be visable and well monitored, and to be in keeping with its original position at the MCA where a car should be yet protected from road hazzards .

31. Landscape design for north resident hall and commons by studio gang
The University is undergoing a period of construction so finding a site must be included in a current planning phase. The committee for campus art has just recommended the sculpture's inclusion in the landscape for the new North Resident Hall designed by Studio Gang. It would be in the area where a road ‘used to be’ – Greenwood Ave’ close to the Smart Museum and Art History Department, making a statement of the commitment to the Arts in this part of the campus and highlighting the significance of the sculpture in the University collection/
Landscape design for north resident hall and commons by studio gang
Due for completion in 2016