Transcript Document

Progress Report on
O’Hare Modernization Plan
Concrete Mix Designs
University of Illinois
Department of Civil and
Environmental Engineering
February 8, 2004
Concrete Mix Design Team
Prof. David Lange
Concrete materials / volume stability
High performance concrete
Prof. Jeff Roesler
Concrete pavement design issues
Concrete materials and testing
Graduate Research Assistants
Cristian Gaedicke
Concrete mix design / fracture testing
Sal Villalobos
Concrete mix design and saw-cut timing
Rob Rodden
testing, instrumentation, shrinkage
Zach Grasley
Concrete volume stability
Overview of Project Objectives
Mix Design
Minimize cracking potential
 Short and long-term
Minimize Shrinkage
Joint Enhancement
Aggregate Interlock
Targeted dowel placement
Group
1
Mechanical Properties
2
Volume Stability
3
Load Transfer
Objectives
Max. Gf (Crack resistance)
Max. lch (ductility)
Min. Shrinkage
Max. Aggregate Interlock
Completed 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 Mixes
Mix Id.
Water
Type I Cement
Type C Fly Ash
Coarse aggregate (# 57
Limestone, 1" max size. )
Fine aggregate
Steel Fibers
Air entrainment admixture
(Excel Air)
Water Reducer (Excel Redi
Set)
Properties
W/CM
fr7
fr28
Air
Slump
Proposed
Mix #1905
(2000)
280
541
135
Revised
Mix #1905
(2000)
262
588
100
Proposed
Mix #1933
Mix #1994
(2000)
(2000)
280
262
588
588
100
130
Mix K-5
003Units
00(2004)
258
lb/yd3
541
lb/yd3
135
lb/yd3
1850
1850
1850
1800
1840
lb/yd3
1125
0
1103
0
1115
0
1100
85
1117
0
lb/yd3
lb/yd3
N/A
7
N/A
N/A
6.8
oz/yd3
29
15
28
29
30.4
oz/yd3
Proposed
Mix #1905
0.41
N/A
N/A
5-8
2
Revised
Mix #1905
0.38
788
1030
5-8
3 +/- 1
Proposed
Mix #1933 Mix #1904
0.41
0.36
802
N/A
842
N/A
5-7
5-8
3 +/- 1
3 +/- 1
Mix K-5
003-00
0.38
770
855
6.2
1
Units
psi
psi
%
in
Survey of Existing Mixes
Airport
Capital
Airport
St. louis
Lambert
St. louis
Lambert
Mix Id.
N/A
Mix 1 F
Mix 4 F
Water
Cement
Type C Fly Ash
GGBS
Coarse aggregate #1
Coarse aggregate #2
Fine aggregate
Fibers
Air entrainment admixture
Water Reducer
233
490
150
1842
1156
N/A
19.6
250
510
80
1866
1225
5.6
14.2
258
535
80
1834
1220
5.6
14.2
St. louis
Lambert
Mix 4 F
w/ fibers
258
535
80
1834
1220
3
5.6
14.2
I
I
I
I
Materials Properties
Cement Type
Coarse aggregate # 1 max.
size. (in)
Coarse aggregate # 2 max.
size. (in)
Fine aggregate type
AEA type
WR type
Fiber type
Concrete Properties
W/CM
fr28
Air
Slump
N/A
-
3/4" (#67) 3/4" (#67)
-
River
Sand
Polychen
AEA Grace
AE VRC
Daracem
Polychen
Grace
MC 400
N/A
-
-
-
-
0.36
770
5.5
4 1/2"
0.42
1033
7.6
2"
0.42
850
7
3 3/4 "
Mix 3 F
Mix 5 F
248
354
88
148
1872
1228
3
17.7
258
310
93
217
1808
1232
3.1
18.6
St. louis
Lambert
Mix 5 F
w/fibers
258
310
93
217
1808
1232
3
3.1
18.6
I
I
I
St. louis
Lambert
St. louis
Lambert
Fort Californ Califor
Wayne
ia
nia
Mix 6 F
Mix P 5
Mix 1
Mix 1
Mix 2
258
372
93
155
1836
1206
3.1
18.6
250
680
1790
1280
N/A
N/A
218
288
192
1424
615
1198
N/A
N/A
300
489
122
1570
400
1165
N/A
N/A
258
479
85
1400
475
1310
1.7
16.92
I
I
I
I
II
1" (57)
1" (57)
3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 3/4" (#67) 1" (57)
-
River Sand River Sand
Polychen
AE VRC
Polychen
MC 400
St. louis St. louis
Lambert Lambert
Polychen
AE VRC
Polychen
MC 400
GRT
Polymesh
fibers
0.42
905
7
3 3/4 "
-
-
-
River
Sand
Polychen
AE VRC
Polychen
MC 400
River
Sand
Polychen
AE VRC
Polychen
MC 400
-
-
River
Sand
Polychen
AE VRC
Polychen
MC 400
GRT
Polymesh
fibers
0.42
700
5
1 1/4 "
0.42
675
5
3"
0.42
675
5
3"
-
-
River
River
Sand
Sand
Polychen
GRT AEA
AE VRC
Polychen GRT KB
MC 400 1000
lb/yd3
lb/yd3
lb/yd3
lb/yd3
lb/yd3
lb/yd3
lb/yd3
lb/yd3
oz/yd3
oz/yd3
1/2 x
#4"
N/A,FM N/A,FM Sechelt
= 2.68 = 2.96 Sand
3/8"
3/8"
N/A
N/A
MBAE
N/A
N/A
Pozz
200N
-
-
-
-
-
0.42
675
5
3"
0.37
1280
6
1 1/2"
0.45
N/A
N/A
N/A
0.49
N/A
N/A
N/A
0.46
767
3
3 1/4"
Units
psi
%
in
Initial Mix Evaluation
Mix used in previous projects at O’Hare
Revised Mix #1905 (2000)
Material
Quantity
Unit
Water
262 lb/yd3
Type I Cement
588 lb/yd3
Type C Fly Ash
100 lb/yd3
Coarse aggregate (# 57
1850 lb/yd3
Limestone, 1" max size. )
Fine aggregate
1103 lb/yd3
Air entrainment admixture (Excel
7 oz/yd3
Air)
Water Reducer (Excel Redi Set)
Properties
fr7
fr28
Air
Slump
15 oz/yd3
Value
788
1030
5-8
3 +/- 1
Unit
psi
psi
%
in
Common Strength Tests
3rd Point Loading (MOR)
Compressive strength and
Concrete elastic modulus
Standard Concrete Shrinkage
Mortar Bar
shrinkage
ASTM
C596
Concrete
shrinkage
prism
ASTM
C157
Initial Mix Evaluation
Compressive strength  4470 psi @ 7days
Modulus of Rupture  380 psi @ 7days
Drying shrinkage  440 mm
Autogenous shinkage 170 mm
Instrumented cube (measurement of RH and Temp.)
Shrinkage(microstrains) vs Age(Days)
0
0
5
10
15
20
25
-50
-100
Micro Strains
-150
-200
-250
Drying
-300
Autogenous
-350
-400
-450
-500
Days
30
Fracture vs. Strength Properties
Brittle
s
MOR
Tough / ductile
GF
Deflection
Peak flexural strength (MOR) same but
fracture energy (GF) is different
Avoid brittle mixes
Fracture Test Setup
Notched Beam Test
Wedge Split Test
Wedge Split Test Result
The concept of GF
Wedge split Gf and lch =EGf/ft2
Load vs Displacement
4000
ft
3500
3000
Load (N)
2500
2000
1500
1000
500
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
CMOD (mm)
GF = Area under the Curve
Cracking Area
0.8
0.9
1
Effect of Aggregate Type on GF
Benefits of SRA in Pavements
Reduced Shrinkage and Cracking Potential
Near 50 –60% reduction
Brooks et al. (2000)
Increased Joint spacing
Problems of SRA in Pavements
Technical
Early age strength loss
Delay in set time
Interaction with air entrainment admixture
Potentially washout with water
Economic
Cost
Fiber-Reinforced Concrete Pavements
Application of low volume, structural fibers
Benefits of FRC Pavements
Increased flexural capacity and toughness
Thinner slabs
Increased slab sizes
Limited impact on construction productivity
Limits crack width
Promotes load transfer across cracks (?)
Use of FRC in Pavements
Fiber-reinforced concrete
225
Plain
0.48% Synthetic Macro Fiber
200
0.32% Synthetic Macro Fiber
175
Load (kN)
150
125
100
75
50
25
0
0
1
2
3
4
5
6
7
8
9
10
11
Average Interior Maximum Surface Deflection (mm)
 Final cost: reduction of 6% to an increase of 11%
12
13
Testing Program
Variables- Phase I
Variables
Aggregate Type
Aggregate Size
Cementitious Content
Fly Ash Content
W/CM
Values
Limestone
1.5 " and 3/4"
600 and 700 lb/yd3
0, 25%
0.4
Proposed Variables- Phase II
Variables
Slag
High Pozzolan Mix
Cememt Type effects
Values
TBD after Phase 1
TBD after Phase 1
TBD after Phase 1
Testing 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
sfl 7 = flexural strength at 7 days
ssp 7 = splitting strength at 7 days
esh = drying shrinkage
eas = autogenous shrinkage
•28-day properties
•Fracture Energy
Joint Type Selection
Are dowels necessary at every contraction joint?
h
Aggregate Interlock Joint
Dummy contraction joint
No man-made load transfer devices
Shear transfer through aggregate/concrete
surface
aggregate type and size; joint opening
Joint Design
Saw-cut timing
Aggregate
Interlock
Targeted
Dowels
Joint Design
Promote high shear stiffness at
joint
High LTE
Larger and stronger aggregates
Increase cyclic loading performance
Predict crack or joint width
accurately
Effect of Concrete Mix on GF
Mix ID
GF (N/m) at 12
hours
GF (N/m) at 28 days
38GTR
194.5
566.2
38mm Trap Rock
38GRG
145.8
573.3
38 mm Gravel
25DTR
114.4
384.9
25mm Trap Rock
25GRG
89.1
252.3
25mm Gravel
25DRG
87.8
208.8
25mm Gravel
25DLS
52.7
93.7
25mm Limestone
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
AGGREGATE GRADATION
Gradation doesn’t have
much impact.
AGGREGATE SIZE
LARGE BETTER THAN SMALL
(38MM)
(25MM)
Other significance of GF
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 Depth
Notch depth (a) depends on stress, strength,
and slab thickness (d)
Stress = f(coarse aggregate,T, RH)
a
d
Requirements for Saw-cut Timing
s
Stress
Strength
Time
Stress = f(thermal/moisture gradients, slab geometry,
friction)
Strength (MOR,E) and fracture parameters (Gf or
KIC) with time
Project Goals
Crack-free concrete (Random)
Specification for shrinkage
Specification for GF
Specifiction for MOR
Optimal joint type
Aggregate Specification
Stabilized base
Saw-cut timing
Cost effective!
Minimum Quantity of Cement
Improvement of Aggregate Interlock
Concrete Mix Design
Minimum strength criteria (MORmin)
Minimum fracture energy (GF)
Max. concrete shrinkage criteria (esh)
Aggregate top size (Dmax)
Strong coarse aggregate (LA Abrasionmax)
Saw-cut timing table
Slow down hydration rates and temperature
Summary of Progress
Concrete Mix Survey Technote
FRC Technote
SRA Technote
Initial Mix Evaluation
Phase I - Testing Program
Saw-Cut Timing
Questions