Progress Report on Progress Report on O’Hare Modernization PlanO’Hare Modernization Plan

February 8, 2004

University of Illinois

Department of Civil and Environmental Engineering

Concrete Mix DesignsConcrete Mix Designs

Concrete Mix Design TeamConcrete Mix Design Team

Prof. David LangeConcrete materials / volume stability

High performance concrete

Prof. Jeff RoeslerConcrete pavement design issues

Concrete materials and testing

Graduate Research AssistantsGraduate Research Assistants

Cristian GaedickeConcrete mix design / fracture testing

Sal VillalobosConcrete mix design and saw-cut timing

Rob Roddentesting, instrumentation, shrinkage

Zach GrasleyConcrete volume stability

Overview of Project ObjectivesOverview of Project ObjectivesMix Design

Minimize cracking potential Short and long-term

Minimize Shrinkage

Joint EnhancementAggregate Interlock

Targeted dowel placement

  Group Objectives

1 Mechanical PropertiesMax. Gf (Crack resistance)

Max. lch (ductility)

2 Volume Stability Min. Shrinkage

3 Load Transfer Max. Aggregate Interlock

Completed ActivitiesCompleted Activities

Survey of Existing Concrete Mixes

Initial Mix and Testing Methods Evaluation

Technote: Shrinkage Reducing Admixtures in

Concrete Pavements

Technote: Fiber-Reinforced Concrete Pavements

Survey of Existing MixesSurvey of Existing Mixes

Mix Id.Proposed Mix #1905

(2000)

Revised Mix #1905

(2000)

Mix #1933 (2000)

Proposed Mix #1994

(2000)

Mix K-5 003-

00(2004)Units

Water 280 262 280 262 258 lb/yd3Type I Cement 541 588 588 588 541 lb/yd3Type C Fly Ash 135 100 100 130 135 lb/yd3Coarse aggregate (# 57 Limestone, 1" max size. )

1850 1850 1850 1800 1840 lb/yd3

Fine aggregate 1125 1103 1115 1100 1117 lb/yd3Steel Fibers 0 0 0 85 0 lb/yd3Air entrainment admixture (Excel Air)

N/A 7 N/A N/A 6.8 oz/yd3

Water Reducer (Excel Redi Set)

29 15 28 29 30.4 oz/yd3

PropertiesProposed Mix #1905

Revised Mix #1905 Mix #1933

Proposed Mix #1904

Mix K-5 003-00

Units

W/CM 0.41 0.38 0.41 0.36 0.38 -fr7 N/A 788 802 N/A 770 psifr28 N/A 1030 842 N/A 855 psiAir 5-8 5-8 5-7 5-8 6.2 %Slump 2 3 +/- 1 3 +/- 1 3 +/- 1 1 in

Survey of Existing MixesSurvey of Existing Mixes

AirportCapital Airport

St. louis Lambert

St. louis Lambert

St. louis Lambert

St. louis Lambert

St. louis Lambert

St. louis Lambert

St. louis Lambert

St. louis Lambert

Fort Wayne

California

California

Mix Id. N/A Mix 1 F Mix 4 FMix 4 F

w/ fibers Mix 3 F Mix 5 F

Mix 5 F w/fibers

Mix 6 F Mix P 5 Mix 1 Mix 1 Mix 2

Water 233 250 258 258 248 258 258 258 250 218 300 258 lb/yd3Cement 490 510 535 535 354 310 310 372 680 288 489 479 lb/yd3

Type C Fly Ash 150 80 80 80 88 93 93 93 - 192 122 85 lb/yd3GGBS - - - - 148 217 217 155 - - - - lb/yd3

Coarse aggregate #1 1842 1866 1834 1834 1872 1808 1808 1836 1790 1424 1570 1400 lb/yd3Coarse aggregate #2 - - - - - - - - - 615 400 475 lb/yd3

Fine aggregate 1156 1225 1220 1220 1228 1232 1232 1206 1280 1198 1165 1310 lb/yd3Fibers - - - 3 - - 3 - - - - lb/yd3

Air entrainment admixture N/A 5.6 5.6 5.6 3 3.1 3.1 3.1 N/A N/A N/A 1.7 oz/yd3Water Reducer 19.6 14.2 14.2 14.2 17.7 18.6 18.6 18.6 N/A N/A N/A 16.92 oz/yd3

Materials PropertiesCement Type I I I I I I I I I I I IICoarse aggregate # 1 max. size. (in)

N/A 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 1" (57) 1" (57) 1" (57)

Coarse aggregate # 2 max. size. (in)

- - - - - - - - - 3/8" 3/8"1/2 x #4"

Fine aggregate type N/ARiver Sand

River Sand River SandRiver Sand

River Sand

River Sand

River Sand

River Sand

N/A,FM= 2.68

N/A,FM= 2.96

Sechelt Sand

AEA type AEA GracePolychen AE VRC

Polychen AE VRC

Polychen AE VRC

Polychen AE VRC

Polychen AE VRC

Polychen AE VRC

Polychen AE VRC

GRT AEA N/A N/A MBAE

WR typeDaracem Grace

Polychen MC 400

Polychen MC 400

Polychen MC 400

Polychen MC 400

Polychen MC 400

Polychen MC 400

Polychen MC 400

GRT KB 1000

N/A N/APozz 200N

Fiber type - - -GRT Polymesh fibers

- -GRT Polymesh fibers

- - - - -

Concrete Properties Units W/CM 0.36 0.42 0.42 0.42 0.42 0.42 0.42 0.42 0.37 0.45 0.49 0.46 -fr28 770 1033 850 905 700 675 675 675 1280 N/A N/A 767 psiAir 5.5 7.6 7 7 5 5 5 5 6 N/A N/A 3 %

Slump 4 1/2" 2" 3 3/4 " 3 3/4 " 1 1/4 " 3" 3" 3" 1 1/2" N/A N/A 3 1/4" in

Initial Mix EvaluationInitial Mix Evaluation

Mix used in previous projects at O’HareRevised Mix #1905 (2000)

Material Quantity Unit Water 262 lb/yd3Type I Cement 588 lb/yd3Type C Fly Ash 100 lb/yd3Coarse aggregate (# 57 Limestone, 1" max size. )

1850 lb/yd3

Fine aggregate 1103 lb/yd3Air entrainment admixture (Excel Air)

7 oz/yd3

Water Reducer (Excel Redi Set) 15 oz/yd3

Properties Value Unit fr7 788 psifr28 1030 psiAir 5-8 %Slump 3 +/- 1 in

Common Strength TestsCommon Strength Tests

3rd Point Loading (MOR) Compressive strength and Concrete elastic modulus

Standard Concrete ShrinkageStandard Concrete Shrinkage

Mortar Bar shrinkage

ASTM C596

Concrete shrinkage

prism

ASTM C157

Initial Mix EvaluationInitial Mix Evaluation

Compressive strength 4470 psi @ 7daysModulus of Rupture 380 psi @ 7daysDrying shrinkage 440 mAutogenous shinkage 170 mInstrumented cube (measurement of RH and Temp.)

Shrinkage(microstrains) vs Age(Days)

-500

-450

-400

-350

-300

-250

-200

-150

-100

-50

0

0 5 10 15 20 25 30

Days

Mic

ro S

trai

ns

Drying

Autogenous

Fracture vs. Strength PropertiesFracture vs. Strength Properties

Peak flexural strength (MOR) same but fracture energy (GF) is different

Avoid brittle mixes

Deflection

Tough / ductile

Brittle

GF

MOR

Fracture Test SetupFracture Test Setup

Wedge Split Test

Notched Beam Test

Wedge Split Test ResultWedge Split Test Result

The concept of GF

Wedge split Gf and lch =EGf/ft2

Load vs Displacement

0

500

1000

1500

2000

2500

3000

3500

4000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1CMOD (mm)

Lo

ad

(N

)

ft

GF = Area under the Curve Cracking Area

Effect of Aggregate Type on GEffect of Aggregate Type on GFF

Benefits of SRA in Pavements Benefits of SRA in Pavements

Reduced Shrinkage and Cracking Potential Near 50 –60% reduction

Increased Joint spacing Brooks et al. (2000)

Problems of SRA in PavementsProblems of SRA in Pavements

Technical Early age strength lossDelay in set timeInteraction with air entrainment admixturePotentially washout with water

EconomicCost

Fiber-Reinforced Concrete PavementsFiber-Reinforced Concrete Pavements

Application of low volume, structural fibers

Benefits of FRC PavementsBenefits of FRC Pavements

Increased flexural capacity and toughnessThinner slabs

Increased slab sizes

Limited impact on construction productivity

Limits crack width

Promotes load transfer across cracks (?)

Use of FRC in Pavements Use of FRC in Pavements

Fiber-reinforced concrete

Final cost: reduction of 6% to an increase of 11%

0

25

50

75

100

125

150

175

200

225

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Average Interior Maximum Surface Deflection (mm)

Lo

ad

(k

N)

Plain

0.48% Synthetic Macro Fiber

0.32% Synthetic Macro Fiber

Testing ProgramTesting Program

Variables- Phase I

Variables ValuesAggregate Type LimestoneAggregate Size 1.5 " and 3/4"Cementitious Content 600 and 700 lb/yd3Fly Ash Content 0, 25%W/CM 0.4

Proposed Variables- Phase II

Variables ValuesSlag TBD after Phase 1High Pozzolan Mix TBD after Phase 1Cememt Type effects TBD after Phase 1

Testing FactorialTesting Factorial

Where: fc’7 = compressive strength at 7 days

E 7 = modulus of elasticity at 7 days

Gf 7 = energy release rate at 7 days

fl 7 = flexural strength at 7 days

sp 7 = splitting strength at 7 days

sh = drying shrinkage

as = autogenous shrinkage

fc' 7

E 7

Gf7 fl 7

sp

7

sh

as

FA=0%FA=25%FA=0%FA=25%FA=0%FA=25%FA=0%FA=25%

CM= 600 lb/yd3

CM= 700 lb/yd3

AG

G =

3

/4"

WC

M

= 0

.4 CM= 600 lb/yd3

Typical O Hare mix

Proposed Independent Variables: Proposed Dependent Variables:

CM= 700 lb/yd3Ag

gre

ga

te T

ype

AG

G =

1.5

"

WC

M =

0

.4

•28-day properties

•Fracture Energy

Joint Type SelectionJoint Type Selection

Are dowels necessary at every contraction joint?

h

Dummy contraction joint

No man-made load transfer devices

Shear transfer through aggregate/concrete surface

aggregate type and size; joint opening

Aggregate Interlock JointAggregate Interlock Joint

Joint Design Joint Design

Saw-cut timing

Aggregate Interlock

Targeted Dowels

Joint Design Joint Design

Promote high shear stiffness at joint

High LTE

Larger and stronger aggregatesIncrease cyclic loading performance

Predict crack or joint width accurately

Effect of Concrete Mix on GEffect of Concrete Mix on GFF

Mix IDGF (N/m) at 12

hoursGF (N/m) at 28 days

38GTR 194.5 566.2

38GRG 145.8 573.3

25DTR 114.4 384.9

25GRG 89.1 252.3

25DRG 87.8 208.8

25DLS 52.7 93.7 25mm Limestone

25mm Gravel

25mm Trap Rock

38mm Trap Rock

38 mm Gravel

25mm Gravel

GF and Shear Load Transfer

•Shear load transfer depends on GF at 28 days.•Concrete with high GF at 28 days provides good shear load transfer across cracks/joints.

AGGREGATE TYPE

TRAP ROCK > RIVER GRAVEL > LIMESTONE

Gradation doesn’t have much impact.

AGGREGATE SIZE

LARGE BETTER THAN SMALL (38MM) (25MM)

Other significance of GOther significance of GFF

GF better characterize the effect of CA on concrete performance.w/c = 0.49 fc’ (12 hrs) = 3.80 – 4.20 MPa fc’ (28 days) = 31.7 – 38.1 MPa

GF (12 hrs) = 52.7 – 194.5 N/m

GF (28 days) = 93.7 – 573.3 N/m

Saw-cut Timing and DepthSaw-cut Timing and Depth

Notch depth (a) depends on stress, strength, and slab thickness (d)

Stress = f(coarse aggregate,T, RH)

d

a

Requirements for Saw-cut TimingRequirements for Saw-cut Timing

Stress = f(thermal/moisture gradients, slab geometry, friction)

Strength (MOR,E) and fracture parameters (Gf or KIC) with time

Time

StrengthStress

Project GoalsProject Goals

Crack-free concrete (Random)Specification for shrinkageSpecification for GF

Specifiction for MOR

Optimal joint typeAggregate SpecificationStabilized base

Saw-cut timing

Cost effective!Minimum Quantity of CementImprovement of Aggregate Interlock

Concrete Mix DesignConcrete Mix Design

Minimum strength criteria (MORmin)

Minimum fracture energy (GF)

Max. concrete shrinkage criteria (sh)

Aggregate top size (Dmax)

Strong coarse aggregate (LA Abrasionmax)

Saw-cut timing table

Slow down hydration rates and temperature

Summary of ProgressSummary of Progress

Concrete Mix Survey Technote

FRC Technote

SRA Technote

Initial Mix Evaluation

Phase I - Testing Program

Saw-Cut Timing

Questions