1. Principal Investigators
Concrete (PCC) Mixture Designs for O’Hare Modernization Program
Principal Investigators
Prof. Jeff Roesler
Prof. David Lange
PROJECT GOAL
Investigate cost-effective concrete properties and pavement design features required to achieve long-term rigid pavement performance at Chicago O’Hare International.

2. Acknowledgements Principal Investigators Prof. Jeff Roesler
Prof. David Lange
Research Students
Cristian Gaedicke
Victor Cervantes

3. Former OMP Research Students
Sal Villalobos – CTL, Inc. (Chicago area)
Civil engineer
Robert Rodden – American Concrete Pavement Association (Chicago area)
Technical director
Zach Grasley – Texas A&M
Materials professor

4. Project Objectives
Develop concrete material constituents and proportions for airfield concrete mixes
Strength
volume stability
fracture properties
Develop / improve models to predict concrete material behavior
Crack width and shrinkage
Evaluate material properties and structural design interactions
joint type & joint spacing (curling and load transfer)
Saw-cut timing

5. FY2005-06 Accomplishments Tech Notes (TN) -
TN2: PCC Mix Design
TN3: Fiber Reinforced Concrete for Airfield Rigid Pavements
TN4: Feasibility of Shrinkage Reducing Admixtures for Concrete Runway Pavements
TN11: Measurement of Water Content in Fresh Concrete Using the Microwave Method
TN12: Guiding Principles for the Optimization of the OMP PCC Mix Design
TN15: Evaluation, testing and comparison between crushed manufactured sand and natural sand
TN16: Concrete Mix Design Specification Evaluation
TN17: PCC Mix Design Phase 1

6. FY2006 Accomplishments Tech Notes (TN) -
TN21: An Overview of Ultra-Thin Whitetopping Technology
TN23: Effect of Large Maximum Size Coarse Aggregate on Strength, Fracture and Shrinkage Properties of Concrete
TN24: Concrete Saw-Cut Timing Model
TNXX: Recycled Concrete Aggregate Concrete (80%)
TNYY: Functionally Layered Concrete Pavements (70%)
TNZZ: Properties of concrete containing GGBFS
TNAA: Effects of Concrete Materials and Geometry on Slab Curling (40%)
Mention May 17, 2006 meeting for spec writing.

7. Presentation Overview
2006 Topics – TN & Brown Bag
Large-sized coarse aggregate mixtures
Slab Curling –theoretical analysis
Saw-cut timing model
Recycled Concrete Aggregate
P-501 Accomplishments
P-501 Remaining Items
Field Demo Project
Future Work

8. Phase II Mix Summary Larger-size coarse aggregate
Effect of larger-size
coarse aggregate on
strength
Larger-size coarse aggregate

9. Drying Shrinkage – Phase II
Effect of larger-size
coarse aggregate on
shrinkage

10. Fracture Energy Results-Phase II
Effect of larger-size
coarse aggregate on fracture
properties
Age = 28-days

11. PCC Mix Design – Phase II
Summary*
Larger aggregates reduce strength by 20%, but…
28-day GF similar  similar cracking resistance
Larger aggregates reduce concrete brittleness
1-day fracture energy  with larger MSA
 greater joint stiffness / performance
No significant shrinkage difference
TN23 – April 2006
*Roesler, J., Gaedicke, C., Lange, Villalobos, S., Rodden, R., and Grasley, Z. (2006), “Mechanical Properties of Concrete Pavement Mixtures with Larger Size Coarse Aggregate,” accepted for publication in ASCE 2006 Airfield and Highway Pavement Conference, Atlanta, GA.

12. P-501 Accomplishments No fly ash replacement ratio
ASTM C157 <0.045% at 28-days*
MSA 1.5 inch*
Design strength 650 psi and specified strength =620 psi
Min. cement content =535 lb/yd3
Min. w/cm 0.4 & max 0.45
Need to modify ASTM C157 to say moisture cure for 24 hours and then begin drying.

13. P-501 Remaining Issues Nominal vs. Maximum Size Aggregate
Combined Gradation
ASTM C1157 – blended cements
Performance spec
Air content
5.5% for 1.5inch MSA
Slag

14. ASTM C 1157

15. Combined Gradation

16. Air content 4

17. Gradation

18. Mix Workability

19. Retained Spec
8 to 18%
Min 13% on consecutive sieves

20. Saw-Cut Timing and Depth
Process
Concrete Mix
Aggregate size
Cementitious content
Crack Propagates
FRACTURE PROPERTIES
Wedge Split Test
FEM Model
Saw Cut Depth Model

21. Summary of Notch Depth Requirements

22. Recycled Concrete Aggregate (RCA) Objectives
Determine the fracture properties of concrete
virgin and recycled coarse aggregate
w/ and w/o structural fibers
Effects of concrete drying shrinkage with recycled coarse aggregate

23. Results – Virgin vs RCA Similar peak loads
Virgin GF is 1.6 times larger than RCA GF

24. Results – Virgin FRC vs RCA FRC
Similar peak loads
Similar softening curves
Similar GF

25. RCA Shrinkage

26. Concrete Slab Behavior
Curling stresses
temperature
moisture
Joint Opening
Load transfer
Dowel vs. no dowel

27. Hygro-thermal Strain (1)
Quantify the drying shrinkage due to RH change
Micro-mechanical model: modified Mackenzie’s formula

28. Hygro-thermal Strain (2)
Kelvin-Laplace equation

29. Slab-base friction Expansion caused by friction (after K.P. George)
L: joint spacing
Expansion caused by friction (after K.P. George)

30. Joint opening ()

31. Field Validation
Field data: three concrete slabs were cast on 06/22/06 at ATREL
Slab size: 15’x12’x10’’, BAM
Temp., RH surface, 1’’,3’’,5’’,7’’ and 9’’ at 15-min. interval
Two LVDTs installed in each joint to measure joint opening

32. Joint Opening Measurement

33. Two week joint opening
Joint opening consistent between bonded and debonded base area. This means the opening is a surface phenomena (highly dependent on shrinkage and temperature at surface). How does the slab length play a role and Creep? Shrinkage is playing a large role in the opening. Average temperature movement per day is 0.03 inches which is about as high as you are going to be (uniform change in temp is probably 25F)

34. Two month joint opening
Joint opening consistent between bonded and debonded base area. This means the opening is a surface phenomena (highly dependent on shrinkage and temperature at surface). How does the slab length play a role and Creep? Shrinkage is playing a large role in the opening. Average temperature movement per day is 0.03 inches which is about as high as you are going to be (uniform change in temp is probably 25F)

35. Concrete Free Shrinkage

36. Material inputs Setting temp. T= 50°C (122°F)
=5.75 x 10-6/ °F (10.35 x 10-6/ °C)
K=2.12 x 106 psi
Ks=3.77 x 106 psi
E=4.03 x 106 psi
Unit weight =149 pcf
Friction coeff. = 2.5
Data set: 0:08a.m. on 07/01/06 –12:38p.m. on 07/13/06 at 15-min. interval

37. Predicted joint opening(1)

38. Predicted joint opening(2)
How to link moisture gradient with materials?

39. Next step Curling effect – in progress
Visco-elastic property of concrete material: creep and stress relaxation
Hereditary integral should be applied in calculating strain (Boltzmann, Volterra,McHenry)

40. Future Work

41. Concrete Pavement / Material Interaction
Hygro-thermal effects on slab behavior
Curling & joint opening (slab sizes)
Dowel
Construction practices (curing, temp, mix components)
Early & long age
Material effects (e.g.)
Combined gradation*
Slag
High early strength/stiffness
FRC

42. Surface Energy Balance
Solar radiation
Reflected radiation
Convection
Wind
PCC slab
Conduction
BAM
ASB
Subgrade
Conduction

43. N-layer Heat Transfer Model
B.C.s
Layer 1
Layer 2
Layer n
Governing PDE

44. QUESTIONS
Thanks!

45. Curling Questions How does shrinkage effect slab size?
What are the combined effect of moisture/temperature profile?
What is the role concrete creep?
How do other concrete materials behave – FRC & SRA?

46. Slab Curling
Effects of materials and slab geometry on moisture and temperature curling  s
Time
Stress
after Grasley (2006) & Rodden (2006)

47. Field vs Lab
Lab
Field

48. Ground Granulated Blast Furnace Slag GGBFS

49. Introduction By product of the steel industry
Produced in blast furnaces
Highly cementitious
Hydrates similarly to Portland cement

50. it is then ground to a fine power
Production
Iron blast furnace slag is quenched…
it is then ground to a fine power

51. Pros and Cons Cons Pros Improves workability Lower water demand
Higher paste volume
Higher strength potential
Using 120 grade
Longer setting time
Decreased permeability
Performs well in freeze thaw tests
Reduces the effects of ASR
Reduced heat of hydration*
More susceptible to drying shrinkage
Slower strength gain*

52. Slag Activity Index
Higher grade GGBFS can be used in larger percentages
Improves early and ultimate performance
ASTM C989