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.
Acknowledgements
Principal Investigators
Prof. Jeff Roesler
Prof. David Lange
Research Students
Cristian Gaedicke
Sal Villalobos
Rob Rodden
Zach Grasley
Others students
Hector Figueroa
Victor Cervantes
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
FY2005-06 Accomplishments
Tech Notes (TN) -
www.cee.uiuc.edu/research/ceat
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
FY2006 Accomplishments
Tech Notes (TN) -
www.cee.uiuc.edu/research/ceat
TN21: An Overview of Ultra-Thin Whitetopping
Technology
TN23: TN23: Effect of Large Maximum Size Coarse
Aggregate on Strength, Fracture and Shrinkage Properties
of Concrete
TNXX: Effects of Concrete Materials and Geometry on
Slab Curling
TNYY: Concrete Saw-Cut Timing Model
TNZZ: Functionally Layered Concrete Pavements
Presentation Overview
Large-sized coarse aggregate mixtures
Saw-cut timing model
Slab Curling
Field Demo Project
Recycled Concrete Aggregate
Aggregate Interlock Joints
Reduced LTE with small maximum size CA
Dowels deemed necessary
Crack width, cw
Aggregate Interlock Joints
Larger maximum size CA
Larger aggregate top size increases aggregate
interlock and improves load transfer
Crack width, cw
Why Larger Size Coarse Aggregate?
Potential benefits
Less paste  lower cementitious content
 Shrinkage
Higher toughness
 Fracture and crack propagation resistance
Increase roughness of joint surfaces
 Increased load transfer between slabs
 Reduced # of dowels
Durability (??)
 D-cracking
Cost - Effectiveness
Experimental Design
Effect of aggregate size (1.0” vs. 1.5”)
Effect of 1.5” coarse aggregate:
Total cementitious content:
 688 lb/yd3, 571 lb/yd3, 555 lb/yd3 and 535 lb/yd3
Water / cementitious ratio:
 0.38 versus 0.44
Fly Ash / cementitious ratio:
 14.5% versus 0%
Effect of coarse aggregate cleanliness
Mix Design Results
ID
water (lb/yd3)
cement (lb/yd3)
fly ash (lb/yd3)
CA (lb/yd3)
FA (lb/yd3)
AEA (oz/yd3)
w/cm
CA/ FA
cm
w/c
Fl\y Ash/ CM
688.38 (1.5" 688.38
CA) CLEAN standard
688.44
688.38
571.44
571.38 571.44 Nof 535.44
555.44
AGG
(3/4 " CA) (1.5" CA) (1.5" CA) (1.5" CA) (1.5" CA) (1.5" CA) (1.5" CA) (1.5" CA)
261
262
303
261
251
217
251
235
244
588
588
588
588
488
488
571
535
455
100
100
100
100
83
83
0
0
100
1842
1850
1772
1842
1924
1982
1938
1984
1942
1083
1103
1042
1083
1132
1166
1140
1167
1142
19.4
12.7
19.4
19.4
16.1
16.1
16.1
15.1
15.6
0.38
0.38
0.44
0.38
0.44
0.38
0.44
0.44
0.44
1.7
1.68
1.7
1.7
1.7
1.7
1.7
1.7
1.7
688
688
688
688
570.96
570.96
571
535
555
0.44
0.45
0.51
0.44
0.51
0.44
0.44
0.44
0.54
0.15
0.15
0.15
0.15
0.15
0.15
0.00
0.00
0.18
Slump (in)
Air (%)
6.13
7.0
7.63
6.5
9.00
6.0
6.25
8.0
7.38
2.9
2.50
7.3
2.25
6.5
8.63
2.9
7.88
3.7
Density (pcf)
143.8
145.1
141.8
141.8
150.4
143.9
146.2
150.9
150.2
fs7 (psi)
362
526
275
440
412
416
505
390
480
570
423
454
513
429
524
415
490
4,045
3,267
3,241
3,608
3,369
3,329
2,338
3,327
4,217
4,131
3,785
4,344
3,744
5,366
3,369
4,212
3,476
4,177
4,031
3,879
4,224
3,326
3,426
3,692
#¡DIV/0!
3,752
3,695
3,438
4,204
3,881
3,958
3,311
4,209
#¡DIV/0!
802
668
639
688
651
794
619
663
fs28 (psi)
fc7 (psi)
fc28 (psi)
Ec7 (psi)
Ec28 (psi)
MOR28 (psi)
#¡DIV/0!
3,393
#¡DIV/0!
3,236
Phase II Mix Summary
Mixture ID
Coarse Aggregate Size (in)
Coarse Aggregate (lb/yd3)
Fine Aggregate (lb/yd3)
Water (lb/yd3)
Cement (lb/yd3)
Fly ash (lb/yd3)
Air (oz/yd3)
Slump (in.)
Air Content (%)
Unit Weight (lb/ft3)
Mixture ID
fsp28 (psi)
MOR28 (psi)
E28 (ksi)
688.38ST
0.75
1850
1103
262
588
100
12.7
7.5
6.5
145.1
688.38ST
570
802
3,752
688.38
1.5
1842
1083
261
588
100
19.4
6.25
8
141.8
688.38
454
639
3,438
571.44
1.5
1938
1140
251
571
0
16.1
2.25
6.5
146.2
571.44
524
794
3,958
555.44
1.5
1942
1142
244
455
100
15.6
8.0
3.7
150.2
Effect of larger-size
coarse aggregate on
strength
555.44
490
663
4,209
Larger-size coarse aggregate
Drying Shrinkage – Phase II
Total Shrinkage vs. Age
Shrinkage (microstrain)..
500
400
Effect of larger-size
coarse aggregate on
shrinkage
300
\
200
688.38 st
688.38
100
571.44
555.44
0
0
5
10
15
20
25
30
Concrete Age (days)
Mixture ID
sh3 (microstrain)
sh7 (microstrain)
sh14 (microstrain)
sh28 (microstrain)
688.38 st
688.38
571.44
555.44
48
193
292
417
118
233
338
405
139
250
320
380
52
158
273
335
Fracture Energy Results-Phase II
688.38 st
156
Mixture ID
GF (Nm)
688.38
166
3000
688.38st
688.38
555.44
Fv (N)
2000
1500
1000
500
0
0
0.5
1
CMOD(mm)
Age = 28-days
1.5
555.44
161
Effect of larger-size
coarse aggregate on fracture
properties
Load vs. CMOD curves for Wedge Splitting Samples
2500
571.44
N/A
2
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.
Saw-Cut Timing Model
Concrete E and fracture properties(cf ,KIC) at early
ages.
Develop curves of nominal strength vs notch depth
for timing.
a
d
Nominal strength vs ao/d for the 300mm slab
1.20
ls@6hr
Nominal strength
1.00
•Notch depth (a) depends on stress,
strength, and slab thickness (d)
ls@12hr
rg@6hr
0.80
rg@12hr
0.60
0.40
•Stress = f(coarse aggregate,T,RH)
0.20
0.00
0.000
0.100
0.200
0.300
ao/d
0.400
0.500
0.600
Saw-Cut Timing and Depth
Saw cut depth / timing – EXPERIENCE
Fracture properties at early ages
Critical Stress Intensity Factor (KIC)
Critical Crack Tip Opening Displacement
(CTOCC) form this type of specimen
Wedge Splitting Test (WST)
 need geometric factors
a
d
Saw-Cut Timing and Depth
Process
Concrete Mix
• Aggregate size
• Cementitious content
Crack Propagates
Tensile strength of the slab at 12 hours
FRACTURE
PROPERTIES
Nominal strengthMPa)
1.00
0.80
688.38ST
0.60
0.40
0.20
0.00
0.00
Wedge Split Test
FEM Model
688.38
0.10
0.20
0.30
ao/d
0.40
Saw Cut Depth
Model
0.50
Wedge Split Testing
WST setup and specimen
80mm
40mm 80mm
200 mm
b
a
t
205mm
Notch detail
200 mm
30mm
57mm
2mm
a = a/b
Saw-Cut Timing and Depth
FEM Model
200 mm
Special Mesh
around crack tip
Q8 elements
Symmetry and BC
considerations
100 mm
Saw-cut timing and depth
FEM Model Results
Determination of Fracture parameters
K IC  Psmax *
f1 (a )
t * b1/2
K IC 
f1 vs a/b
5.0
4.5
Psmax
* f1 (a )
t * b1/2
y = 9.8214x - 1.4584
R2 = 0.9779
f1
4.0
3.5
y = 25.598x 2 - 15.757x + 4.8066
R2 = 0.9996
3.0
2.5
2.0
0.40
0.42
0.44
0.46
0.48
0.50
a/w
0.52
0.54
0.56
0.58
0.60
Saw-cut timing and depth
FEM Model Results
Determination of Fracture parameters
CMOD  Psp *
f 2 (a )
CMOD 
t *E
Psp
t *E
CTOD  f 3 (a ) * CMOD
y = 207.07x - 58.121
R2 = 0.9736
2
K IC
f3 vs a/b
0.35
60.0
0.3
50.0
0.25
40.0
30.0
y = 1.2088x - 0.3456
R2 = 0.9847
0.2
y = -3.3883x 2 + 4.7542x - 1.2625
R2 = 0.9991
0.15
20.0
y = 590.13x 2 - 382.59x + 86.31
R2 = 0.9995
0.1
10.0
0.0
0.40
CTODC*E
0.4
f3
f2
70.0
cf 
f2 vs a/b
80.0
* f 2 (a )
0.05
0.42
0.44
0.46
0.48
0.50
a/w
0.52
0.54
0.56
0.58
0.60
0
0.40
0.42
0.44
0.46
0.48
0.50
a/w
0.52
0.54
0.56
0.58
0.60
Saw-Cut Depth Model
Tensile strength of the slab at 6hrs
SEM Model (Bazant)
Nominal strength(MPa)
σt
0.30
c n K IC
g'(a o /d)c f  g(a o /d)d
0.25
555.44
0.20
555.44ST
0.15
0.10
0.05
cf 
CTODC*E
K
K IC 
2
IC
Psmax
* f1 (a )
t * b1/2
0.00
0.00
0.10
0.20
ao/d
0.30
0.40
0.50
Nominal Strength vs Notch Depth Chart
g a /d   παc f a /d 
g' a /d   πf a /d   2παcn f a /d  f'a /d 
2
n
o
2
o
o
2
o
o
o
f a /d   1.12  0.203α-1.197 α  1.93α
2
o
f' a /d   0.203  2.394α  5.79 α
o
2
3
Saw-cut timing and depth
Concrete
Mix proportions
ID
Units
w/cm
555.44
555.44 st
0.44
688.38
688.38 st
0.38
Max aggregate size
mm (inch)
38 (1 1/2")
25 (1")
38 (1 1/2")
25 (1")
Water
kg/m3
145
145
155
155
Cement
kg/m3
270
270
349
349
Fly ash
kg/m3
59
59
59
59
Coarse Aggregate (SSD)
kg/m3
1152
1142
1093
1098
672
643
654
678
kg/m3
All mixtures were air entrained rangin from 4% to 8%
Fine Aggregate (SSD)
Aggregate gradations
Coarse Aggregate 11/2 inch max. size
BSG=2.71 AC= 1.27%
Sieve
Opening Retained
(%)
1.5"
1"
3/4"
1/2"
3/8"
#4
Total
0
59
34
7
1
0
100
Cumulative
retained (%)
0
59
92
99
100
100
Coarse Aggregate
BSG=2.67
3/4 inch max. size
AC= 2.0%
Cumulative
Cumulative Cumulative
Retained (%)
passing (%)
retained (%) passing (%)
100
41
8
1
0
0
0.00
0.00
32.55
55.70
8.82
2.94
100.00
0.00
0.00
32.55
88.25
97.06
100.00
100.00
100.00
67.45
11.75
2.94
0.00
Concrete Fracture Properties
Critical Stress Intensity Factor (KIC)
AGE
555.44
(hr)
(days)
0
6
8
10
12
0
0.25
0.33
0.42
0.50
0.0
0.01
0.05
0.08
0.19
MIXTURE
555.44st
688.38
KIC (Mpa-m1/2)
0.0
0.01
0.03
0.14
0.15
688.38st
0.0
0.02
0.07
0.14
0.32
0.0
0.02
0.06
0.11
0.25
MIXTURE
555.44st
688.38
688.38st
Critical Crack Extension (cf)
AGE
(hrs)
6
8
10
12
555.44
0.001
0.005
0.006
0.006
c f (m)
0.003
0.008
0.008
0.023
0.002
0.007
0.012
0.024
0.001
0.004
0.006
0.018
Curling Stress in Concrete Slab
Tensile strength of the slab at 6hrs
Westergaard Slab Curling
σ
C  1
CEαT
2( 1-ν)
2 cos λ cosh λ( tan λ  tanh λ)
sin 2 λ sinh 2 λ
Eh 3
l4
L
12( 1  v 2 )k
λ
l 8
AGE (hr)
MIXTURE
688.38
555.44
6
0.15
0.18
8
10
Stress (Mpa)
0.20
0.25
0.24
0.30
Nominal strength(MPa)
0.30
0.25
555.44
0.20
555.44ST
0.15
0.10
0.05
0.00
0.00
0.10
0.20
ao/d
Saw cut
Depth
12
0.30
0.37
0.30
0.40
0.50
Low Cementitious Content
Saw Cut Depth Charts
Tensile strength of the slab at 8hr
Tensile strength of the slab at 6hrs
0.40
Nominal strength(MPa)
Nominal strength(MPa)
0.30
0.25
555.44
0.20
555.44ST
0.15
0.10
0.30
555.44
555.44ST
0.20
0.10
0.05
0.00
0.00
0.10
0.20
0.30
0.40
0.00
0.00
0.50
0.10
0.50
555.44
555.44ST
0.30
0.20
0.10
0.10
0.20
0.30
ao/d
0.40
0.50
Tensile strength of the slab at 12 hours
1.00
Nominal strength(MPa)
Nominal strength (MPa)
Tensile strength of the slab at 10 hours
0.60
0.00
0.00
0.30
ao/d
ao/d
0.40
0.20
0.40
0.50
0.80
555.44
555.44ST
0.60
0.40
0.20
0.00
0.00
0.10
0.20
ao/d
0.30
0.40
0.50
High Cementitious Content
Saw Cut Depth Charts
Tensile strength of the slab at 6 hours
Tensile strength of the slab at 8 hours
0.50
0.25
Nominal strength(MPa)
Nominal strength(MPa)
0.30
688.38
0.20
688.38ST
0.15
0.10
0.05
0.00
0.00
0.10
0.20
0.30
0.40
0.40
688.38
0.30
0.20
0.10
0.00
0.00
0.50
688.38ST
0.10
ao/d
Tensile strength of the slab at 10hours
0.40
0.50
Tensile strength of the slab at 12 hours
0.80
1.00
0.70
0.60
688.38
0.50
688.38ST
Nominal strengthMPa)
Nominal strength(MPa)
0.20
0.30
ao/d
0.40
0.30
0.20
0.10
0.00
0.00
0.10
0.20
ao/d
0.30
0.40
0.50
0.80
688.38
688.38ST
0.60
0.40
0.20
0.00
0.00
0.10
0.20
0.30
ao/d
0.40
0.50
Summary of Notch Depth
Requirements
Age(hours)
Temp. stress(Mpa)
555.44
Notch depth
555.44st
required
Temp. stress(Mpa)
688.38
Notch depth
688.38st
required
6
0.15
0.05
-----0.18
0.02
0.02
8
0.2
0.07
0.05
0.24
0.08
0.07
10
0.25
0.09
0.09
0.3
0.12
0.09
10
12
0.4
Notch depth (ao/d)
555.44
0.3
555.44st
688.38
688.38st
0.2
0.1
0
6
8
Age (hours)
12
0.3
0.26
0.23
0.37
0.36
0.26
Saw-cut timing and depth
Summary
Saw cut depth increases with concrete age
 dramatic increase in depth after 10 to 12 hr.
Larger maximum aggregate size increases saw cut
depth
 High cementitious materials especially
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?
Slab Curling
 (t , z ) 
Effects of materials
and slab geometry on
moisture and
temperature curling
C (t ) E (t ) ( z ) C (t ) E (t ) T (t , z )   HT (t , z )   CR (t , z ) 

2(1  v)
2(1  v)
 tot   T   HT   CR
 HT ( z ) Total 
  RH ( z )  3  
RT ( z )  1
1 

1

0
.
75

   ln( RH ( z ))
1  


v w  3k 3k 0  
  0.98   
 CR  0.5   HT
Vapor
Diffusion
 HT L NL ( z )   HT ( z ) Total 
h/2
  RH ( z )  3  
1
RT ( z )  1
1 

1

0
.
75

   ln( RH ( z ))dz
1  


h h/ 2 v w  3k 3k 0  
  0.98   

Pc

Stress




Time
after Grasley (2006) & Rodden (2006)
Field vs Lab
Internal RH (%)
100
95
Surface - 1
90
Surface - 2
1/2" - 1
85
1/2" - 2
80
1"
75
5"
70
7"
11" - 1
65
11" -2
60
14" - 1
55
14" - 2
50
8
9
10
11
12
13
14
Elapsed Time (days)
15
100
Field
95
Internal RH (%)
90
0"
85
1/2"
80
1"
75
3"
70
7"
11"
65
14"
60
55
50
Lab
0
5
10
15
Elapsed Time (days)
20
25
30
RH Profile - Lab
-7.5
-6
Location in Slab (in)
-4.5
-3
-1.5
0.6
0.7
0.8
0.9
0
1
1.1
Actual RH
1.5
Second Order
3
4.5
6
7.5
RH (%)
STD Cube Moisture Stresses
0
0
5
10
15
20
25
30
Tensile Stress/Strength (psi)
-100
-200
-300
Tensile Stress
Tensile Strength
-400
-500
-600
-700
Elapsed Time (days)
Summary of Curling
Moisture profile effects
Temperature
Set temperature
Shrinkage Reducing Admixtures
Fiber Reinforced Concrete
Joint Type Analysis
How can we choose dowel vs. aggregate interlock joint
type & joint spacing?
h
Need to predict crack width & LTE
Shrinkage, zero-stress temperature, creep
Aggregate size and type (GF)
Slab length & base friction
If we use aggregate interlock joints there is a significant cost savings
Field Demo Project
Joint Opening Measurement
Two week joint opening
0.12
D
C
A
6/30
7/2
0.1
JOINT-OPENING (in)
B
A
B
C
D
0.08
0.06
0.04
0.02
0
-0.02
6/22
6/24
6/26
6/28
DATE
7/4
7/6
7/8
Shrinkage (mm/mm)…….
Concrete Free Shrinkage
SHRINKAGE 688.38 ST MIX
800
Total shrinkage - Lab Mix
Total shrinkage - Field Mix
Autogrenous shrinkage - Field Mix
600
400
200
0
0
4
8
12
16
20
24
28
Age (days)
Crack Width Model Approach
Step 1: Predict
crack opening, w
Step 2: Predict
differential
deflection, δdiff
Step 3:
Determine
LTE
Step 4:
Acceptable
LTE?
Inputs:
RH, T, L, E, , C
Inputs:
w, CA topsize, 
Inputs:
δfree, δdiff, 
Inputs:
FAA
recommendation
c2i f i 


CWi  CC  L    SHRi  a PCC T 


E
PCC
i


*after Zollinger
Crack spacing
Drying shrinkage
Temperature drop
Restraints
f
i

L U m  P
 2  L
 C 0 1    f
c1i  d b
h  2

Base friction
Curling (thermal and moisture)
Steel reinforcement
Recycled concrete aggregate (RCA)
RCA
Can RCA (coarse) provide similar mechanical
properties for airfield rigid pavements as
virgin aggregates?
Slight strength reduction
Higher shrinkage potential
Lower modulus
Lower concrete density
Potential cost saving ++
UIUC First Trial
RCA from Champaign recycling plant
Concrete came from pavements, parking garages, etc.
Mix of materials with unknown properties
Material washed, dried, and sieved to match natural
fine aggregate
Soaked for 24 hrs, surface dried, and then 100%
replacement of natural fine aggregate
Saturated RCA vs Lab Aggregates
20
Shrinkage strain x 10-6
0
lab stock
lab ssd
RCA SSD
-20
-40
-60
-80
-100
0
5
10
Age (d)
•Similar autogenous shrinkage curves
15
20
Mechanical Property Test Plan
Simple lab crusher
Three Point Bend (TPB) test
 Fracture properties
(Spring 2006)
Full-scale crushing at contractor
Fracture / strength properties
Shrinkage
(Summer 2006)
Sample Preparation
1. Crush Process
Sample Preparation (Con’t)
2. Gradation
3. Mixture Design
Gradation - Maximum size 25 mm
Percentage passing (%)
100
Plain Concrete
80
Mix ID
Material
Water
Type I Cement
Coarse aggregate
Fine aggregate
Synthetic Fibers
60
40
20
0
Particle Size (mm)
# 10
#4
3/8"
1/2"
3/4"
1"
PCC
Kg/m lb/yd3
183
308
360
607
976
1645
807
1360
----3
Synthetic Fiber
Reinforced
Concrete
FRCPP
Kg/m3
lb/yd3
183
308
360
607
976
1645
807
1360
7.2
12.1
Sample Preparation (Con’t)
4. Dimensions
P
80 mm
150mm
50 mm
CMOD
600mm
700mm
Sample Preparation(Con’t)
3 beams
Tested 7 day
Position control
displacement
CMOD = 3 Max
3 Cycles
Load – CMOD curve
Test
Plain Concrete Fracture Behavior
Load (kN)
4
3.5
3
2.5
2
1.5
1
0.5
0
0
PCC
0.4
0.8
RCA
1.2
1.6
2
CMOD (mm)
FRC Fracture Behavior
FRC
RCA w/ Fibers
Fracture Energy
3.5
3
Load (kN)
2.5
Gf 
2
Area Under Plot Load  CMOD
Fracture Area
1.5
1
0.5
0
0
0.2
0.4
CMOD
0.6
0.8
(N/m)
Results (Con’t)
500
450
400
350
300
250
200
150
100
50
0
RCCA
Virgen
RCA
Virgin
Plain
RCA
Virgin
FRC
(N/m)
Results
500
450
400
350
300
250
200
150
100
50
0
Sample 1
Sample 2
Sample 3
Average
RCA
Fiber RCA
RCA vs FRCA
CMOD - LOAD CURVE
4
FRCA # 1
3.5
FRCA # 2
FRCA # 4
RCA # 1
3
RCA # 2
RCA # 3
Load (kN)
2.5
PLAIN
2
1.5
1
0.5
0
0
0.5
1
1.5
2
CMOD
2.5
3
3.5
Summary of Fracture Properties
FRCA - Fracture Energy Pc (N)
(N/m)
KIC (Mpa CTODc
m1/2)
(mm)
Gc (N/m)
Sample 1
Sample 2
Sample 3
329
436
493
2,623
2,627
3,006
0.86
0.80
0.98
0.024
0.021
0.029
36.00
33.03
49.22
Average
C.O.V (%)
420
19.79
2,752
7.99
0.88
10.63
0.025
16.29
39.42
21.87
3,833
1.01
0.013
36.1
12.79%
-92.80%
-9.18%
Virgin Aggregate 399
Difference
-5.15% 28.20%
Initial Findings
RCA reduce the concrete fracture energy by 50%
RCA does not affect the fracture energy in fiber reinforced
concrete (peak load still less)
Summer 2006
RCA Concrete Mixtures
Type of Coarse
Aggregate
Virgin (V)
Recycled (R)
V&R
Fibers
Yes
No
Yes
No
No
Mix ID
VF
VP
RF
RP
MP
Mix date
7.11.06
7.11.06
7.21.06
7.21.06
7.24.06
Mixture
lb/yd3
lb/yd3
lb/yd3
lb/yd3
lb/yd3
Water
308
308
308
308
308
Cement Type I
607
607
607
607
607
Coarse Aggregate
1645
1645
1645
1645
1645
Fine Aggregate
1360
1360
1360
1360
1360
Synthetic Fibers
3
---
3
---
---
BSGSSD = 2.42
AC = 5.7%
RCA Tests
Fresh properteis
Slump, Density, Air
Compressive Strength (7 days)
Split Tensile (7 days)
Three Point Bending at 7days
GF
Gf
CTODc
Drying Shrinkage – 28 days
Work remaining for FY2006
Joint type and size analysis – con’t
Saw-cut timing model - TN
Materials and geometry effects on curling - TN
Functionally-layered concrete pavements - TN
Recycled concrete aggregate – con’t
P
Top
layer
Botto
m
layer
h
ao
1
h
2
h
QUESTIONS
www.cee.uiuc.edu\research\ceat
Thanks!