Concrete (PCC) Mixture Designs for O’Hare Modernization Program

1. 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 • Dong Wang • Yi-Shi Liu • Victor Cervantes • Cristian Gaedicke

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. FY2006 Accomplishments www.cee.uiuc.edu/research/ceat • 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 • TN29: Moisture and Temperature Curling Stresses in Airfield Concrete Pavements • TN30: Fracture Behavior of Functionally Graded Concrete Materials (FGCM) for Rigid Pavements • TN31: Fracture and Drying Shrinkage Properties of Concrete Containing Recycled Concrete Aggregate • TNXX: Overview of GGBFS for Concrete Pavements (95%)

6. Presentation Overview • 2006 Review • Large-sized coarse aggregate mixtures • FGCM • Recycled Concrete Aggregate Concrete • Moisture/Temperature Curling • Saw-cut timing model • Field Demo Project • Crack width-Curling prediction • 2007 Work Plan

7. 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.

8. FGCM Pavement Systems Figure 1. Multifunctional and functionally graded concrete material (FGCM) under temperature (T), relative humidity (RH) and mechanical loading (P), where fi =fiber type and volume content for layer i. Here hi=layer thickness, Ei=elastic modulus, υi=Poisson’s ratio, i=coefficient of thermal expansion Di=diffusivity coefficient, ki=thermal conductivity, and i=layer density

9. Experiment Plain concrete FRC • Composite beams • Single edge notch fracture • PCC and FRC combinations • Full-depth or bi-layered • Material Strength • Compressive • Split-Tensile

10. Numerical vs. Experimental Numerical Results Experimental Results

11. Recycled Concrete Aggregate (RCA) 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

12. Mixture Proportions

13. Results – Virgin, RCA, & 50-50 • Similar peak loads • Virgin GF is similar to the 50-50 GF • Virgin GF is 1.6 times larger than RCA GF

14. Virgin, RCA, & 50-50 with FRC • Similar peak loads • Similar softening curves • Similar GF

15. RCA Shrinkage

16. 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

17. Summary of Notch Depth Requirements

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

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

20. Field vs Lab Lab Field

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

22. Joint Opening Measurement

23. Three month joint opening

24. Joint opening ()

25. Predicted joint opening

26. FY 2007 Work Plan • Objectives: Predict early-age behavior of concrete pavement based on interaction of design, construction techniques, material constituents and proportions, and climatic conditions.

27. FY 2007 Tasks • Concrete Mixture Evaluation • Combined aggregate gradation • GGBFS • Temperature / Moisture Prediction • Construction factors • Mixture variables • Climatic variables • Design factors

28. Principles of Design Optimized Concrete • Minimize Voids to reduce cement paste volume • Higher sand fraction and well graded CA (2 sizes) needed • Polycarboxylate superplasticizer to achieve workability

29. Particle Packing • Continuous grading reduces void volume • Mathematical models can predict max density from particle sizes

30. Properties of DOC • Similar or higher strength compared to OPC • Reduced shrinkage • Reduced bleeding and segregation • Better workability (with vibration) and finishability (no waiting)

31. Cost savings with DOC

32. Ground Granulated Blast Furnace SlagGGBFS

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

34. Pros and Cons 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* Cons Pros

35. GGBFS • Fracture and Strength properties • Shrinkage properties Dan Ryan Expressway mixture

36. Heat Transfer Problem: Early Age Concrete Pavement • Predict temperature profile in concrete pavement at the early age • Sensitivity studies: - Asphalt Concrete initial temperature - Mix/construction temperature (nighttime) - Mixture constituents (cement content / type, thermal properties, etc.) -climatic effects • Construction questions - Curing methods and nighttime construction - Saw-cut timing & curling stresses

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

38. Heat Transfer Model: Theoretical Background N-layer Pav’t system Governing PDE Layer 1 Layer 2 Layer Layer

39. Heat of Hydration • Heat of hydration of cementitious material is modeled as [1] [1]Emborg, M., thermal stresses in concrete structures at early ages, doctoral thesis, Lulea Univ. of Technology, Sweden, 1989

40. Boundary Condition

41. Numerical Methods • Spatial discretization: • Finite difference schemes PCC • Time integrator: • 2nd-order semi-implicit backward • differentiation formula Base Subgrade

42. Sample Results • Temperature profile prediction (no term, based on uniform initial temperature profile T = 40 F, and linear air temperature assumption)

43. Field Data Requirements • Weather data • Air Temperature, wind speed, solar radiation • Concrete final set time • Concrete mixture proportions • Cementitious composition • Field instrumentation • Initial concrete mixture temperature • Curing conditions • Temperature / moisture profile

44. Temp / Moisture Profile Outcome • Concrete Pavement Behavior Predictions • Saw-cut timing and depth • Early-age curling stresses (slab model) • Joint opening prediction

45. QUESTIONS • www.cee.uiuc.edu\research\ceat • Thanks!