01mixtureproportioningb-180530170714

Designing Concrete Mixture Proportions
• Dr. Peter Taylor PE (IL)
• Dr. Xuhao Wang
• Dr. Ezgi Yurdakul

Outline
Introduction
Proportioning:
Paste quality
Aggregate system
Paste quantity
In reality…
3

Proportioning Approaches
Past
• Structural concrete 1:2:4
• Other concrete 1:3:6
• Waterproof concrete
Add salt
• No chemicals
• No SCMs
• Precision was ugly
• Bulking made it worse
4

Proportioning Approaches
Present
• ACI 211
• Last revised in 1991
• Linear
• Developed
• Before water reducers
• Before supplementary cementitious materials
• Primarily focused on structural concrete
• 100 mm (4”) slump
• 30 MPa (~4000 psi)
5

Workability
6

Workability
7

Preconceptions
• More cement = more strength
• Strength is everything
• Slump indicates quality
• Gradations of individual fractions are critical
8

Design
• Choosing what you need
• Workability, setting time
• Durability, strength,
cracking risk
9

Proportioning
10

Proportioning
Filler
Gradation
Glue
What sort
How much
11

Proposed Mixture Proportioning
Procedure
Aggregate
system
Paste Quantity
Paste Quality
Koehler
12

How do we proportion to achieve
design goals?
Workability Transport Strength Cold
weather
Shrinkage
Aggregate
stability
Aggregate System Type, gradation - - - -
Paste quality
Air, w/cm, SCM
type and dose
Paste quantity Vp/Vv - - - -
13

Step 1 Paste Quality
• Binder type
• Cement type
• SCM type and dosage
• w/cm
• ~0.38-0.42
• Air void system
• <0.2 SAM
• <0.008 in. spacing factor
• >5% in place
• Stable
14

Step 2 Aggregate system
• Choices…
• 2 bins or 3?
• ASTM C33
• Or combined:
• Haystack
• Shilstone Plot
• Power 45
• Tarantula
15

Step 2 Aggregate system
• ASTM C33
16

Step 2 Aggregate system
• Haystack
17

Step 2 Aggregate system
• Power 45
18

Step 2 Aggregate system
• Shilstone
19

Step 2 Aggregate system
• Tarantula Curve
20

Step 2 Aggregate system
• What if we got a perfect Power 45
21

Step 2 Aggregate system
• 3 Combinations of the same materials
Traditional Power 45 Tarantula
Coarse Limestone 1" 60.0 47.5 44.9
Fine river sand 30.0 35.3 45.7
Int. Limestone 3/8" 10.0 17.2 9.5
22

Step 2 Aggregate system
• 3 Combinations of the same materials
23

VKelly
• Kelly ball test
• Developed in the 1950s in US
• Standardized in California DOT test
• Comparable to slump test
24

VKelly
• Measure initial slump (initial penetration)
• Start vibrator for 36 seconds at 8000 vpm
• Record depth every 6 seconds
• Plot on root time
• Calculate slope = VKelly Index
25

VKelly Index
0.80 1.1 in/√s
26

VKelly Index
1.1 in/√s
27

Step 2 Aggregate system
• Choose an aggregate system…
28

Step 2 Aggregate system
• Tarantula Curve
29

Step 3 Paste Content
30

Step 3 Paste Content
31

Step 3 Paste Content
32

Workability
33

Strength
34

Air Permeability
35

Rapid Chloride Penetration
36

Shrinkage
37

Step 3 Paste Content
• Effect of aggregate gradation
38

Step 3 Paste Content
• Need a minimum paste for workability
• Excess has a:
• Small negative effect on strength
• Negative effect on permeability, shrinkage, cost
• “Optimum” depends on:
• Aggregate type
• Gradation
• Binder type
• Typically Vv ~125-200%
39

Proposed Mixture Proportioning
Procedure
Aggregate
system
Paste Quantity
Paste Quality
Koehler
40

Doing the Sums
Project Effect of gradation 9/29/2016
Aggregate System
The wonders of
a spreadsheet and a
solver function…
Materials
Blue= Input Data
Red = Calculation Don’t touch!
Cementitious 472 Yellow = Output Don’t touch!
Coarse Agg 1" Black = Working Don’t touch!
Fine Agg
Sand
Intermediate 3/8"
Sieve Analysis Data
Max nominal aggregate size 1.00 inch (0.75, 1.0 or 1.5)
Coarse 1" Fine Sand Intermediate 3/8" Combined Fineness
Percent Cum. Sieve Modulus
Percent mass 100.0 44.9 45.7 9.4 Passing Retained Retained
Sieve: % Pass % Mix % Pass % Mix % Pass % Mix % % %
2" 100.0 44.9 100.0 45.7 100.0 9.4 100.0 0.0 0.0
1 1/2" 100.0 44.9 100.0 45.7 100.0 9.4 100.0 0.0 0.0
1" 99.0 44.4 100.0 45.7 100.0 9.4 99.6 0.4 0.4
3/4" 73.9 33.2 100.0 45.7 100.0 9.4 88.3 11.7 11.3
1/2" 37.5 16.8 100.0 45.7 100.0 9.4 71.9 28.1 16.3
3/8" 19.7 8.8 100.0 45.7 90.2 8.5 63.0 37.0 8.9 0.0
# 4 3.5 1.6 98.6 45.1 21.6 2.0 48.7 51.3 14.4 1.4
# 8 0.8 0.4 88.3 40.3 2.0 0.2 40.9 59.1 7.8 11.7
# 16 0.4 0.2 68.9 31.5 0.6 0.1 31.7 68.3 9.2 31.1
# 30 0.4 0.2 37.0 16.9 0.4 0.0 17.1 82.9 14.6 63.0
# 50 0.3 0.1 9.7 4.4 0.4 0.0 4.6 95.4 12.5 90.3
# 100 0.3 0.1 0.8 0.4 0.3 0.0 0.5 99.5 4.1 99.2
# 200 0.3 0.1 0.2 0.1 0.3 0.0 0.3 99.7 0.3
2.97
Coarsness Factor 62.55 Power 45 least difference 31.0 Tarantula error 0.0 4.5
Workability Factor 40.89 Power 45 error 350.2 113.7
Adjustments 0.00
Adjusted Workability Factor 40.89 Fine 31.5 24-34 23.9 34.1
Coarse 31.5 >15 15
Measure V a
Percent Retained
25
20
15
10
5
Tarantula
Greater than 15% on the sum of #8, #16 and #30
24-34% of fine sand (#30-200)
Percent Passing
100
80
60
40
20
Individual and Combined Gradations
C33
Sand
3/8"
1"
0
2"
1 1/2"
1"
3/4"
1/2"
3/8"
# 4
# 8
Sieve
# 16
# 30
# 50
# 100
# 200
0
# 200 # 100 # 50 # 30 # 16 # 8
Sieve
# 4
3/8" 1/2" 3/4"
1"
Combined
1
1/2"
2"
Power 45
Shilstone Chart
100
80
45
40
IV
Sandy
II
III
Small Agg
% Passing
60
40
20
0
Mixture
Max Density
Limits
#200 #50 #16 #4
1/2"
1" 2"
Sieve (^0.45)
Workability Factor
35
30
25
20
100
I
Gap
80
60
40
Coarseness Factor
V
Coarse
20
0
41

Doing the Sums
The wonders of a spreadsheet…
Paste Quality
Project Effect of gradation 9/29/2016
Materials
Targets
R.D.
Cement Type I 3.15
SCM 1 C Ash 2.65
SCM 2 Slag 1.00
Coarse Agg 1" 2.68
Fine Agg Sand 2.66
Intermediate 3/8" 2.68
Water 1.00
Blue= Input Data
Cementitious 472 pcy Red = Calculation Don’t touch!
w/cm 0.42 Yellow = Output Don’t touch!
Air % 5.0 % Black = Working Don’t touch!
% SCM 1 20 %
% SCM 2 0 %
Voids in aggregate 28.1 %
Required Vp/Vv 125 %
Strength psi 7 days
RCP coulomb 56 days
Wenner kΩ-cm 28 days
42

Doing the Sums
The wonders of a spreadsheet…
Mixture Proportions
Project Effect of gradation 9/29/2016
Mixture Proportions
Targets
Actual
Pounds R.D. Volume
Cement Type I 378 3.15 1.92
SCM 1 C Ash 94 2.65 0.57
SCM 2 Slag 0 1.00 0.00
Coarse Agg 1" 1495 2.68 8.94
Fine Agg Sand 1522 2.66 9.17
Intermediate 3/8" 314 2.68 1.87
Water 198 1.00 3.18
Air % 5.0 1.35 Blue= Input Data
4000 27.00 Red = Calculation Don’t touch!
Yellow = Output
Don’t touch!
Cementitious 472 472 pcy Black = Working Don’t touch!
Volume of paste 26.0 %
Volume of aggs 74.0 %
Volume of voids 20.8
vp/vv 125 125.0 5.2
w/cm 0.42 0.42
% SCM 1 20 20 %
% SCM 2 0 0 %
Mass aggs 3330 3330 pcy
43

Does it Work?
• Local project – as built
44

Trial Batches
• Workability / Admixture dosages / Void ratio
• Air void system
• Setting
• Strength gain
• Permeability
45

Why bother?
• Save money
• Improve Sustainability
• Better product
46