Seminario Internacional de Buenas Prácticas y Mejoramiento del Desempeño de Hormigones para Pavimentos

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

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

4. 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

5. 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

6. Workability
6

7. Workability
7

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

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

10. Proportioning
10

11. Proportioning
Glue
What sort
How much
Filler
Gradation
11

12. Proposed Mixture Proportioning
Procedure
Koehler
Aggregate
system
Paste QualityPaste Quantity
12

13. 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

14. 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

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

16. Step 2 Aggregate system
• ASTM C33
16

17. Step 2 Aggregate system
• Haystack
17

18. Step 2 Aggregate system
• Power 45
18

19. Step 2 Aggregate system
• Shilstone
19

20. Step 2 Aggregate system
• Tarantula Curve
20

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

22. 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

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

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

25. 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

26. VKelly Index
0.80 1.1 in/√s
26

27. VKelly Index
1.1 in/√s
27

28. Step 2 Aggregate system
• Choose an aggregate system…
28

29. Step 2 Aggregate system
• Tarantula Curve
29

30. Step 3 Paste Content
30

31. Step 3 Paste Content
31

32. Step 3 Paste Content
32

33. Workability
33

34. Strength
34

35. Air Permeability
35

36. Rapid Chloride Penetration
36

37. Shrinkage
37

38. Step 3 Paste Content
• Effect of aggregate gradation
38

39. 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

40. Proposed Mixture Proportioning
Procedure
Koehler
Aggregate
system
Paste QualityPaste Quantity
40

41. Doing the Sums
The wonders of
a spreadsheet and a
solver function…
Aggregate System
Project Effect of gradation 9/29/2016
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
0
5
10
15
20
25
2"
11/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
PercentRetained
Sieve
Tarantula
Greater than 15% on thesum of #8, #16 and #30
24-34% of finesand (#30-200)
0
20
40
60
80
100
2"1
1/2"
1"3/4"1/2"3/8"# 4# 8# 16# 30# 50# 100# 200
PercentPassing
Sieve
Individual and CombinedGradations
C33
Sand
3/8"
1"
Combined
0
20
40
60
80
100
%Passing
Sieve (^0.45)
Power 45
Mixture
Max Density
Limits
#50 #16 1" 2"1/2"#4#200
20
25
30
35
40
45
020406080100
WorkabilityFactor
Coarseness Factor
ShilstoneChart
IV
Sandy
I
Gap
II
III
Small Agg
V
Coarse
41
Measure Va

42. 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

43. 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

44. Does it Work?
• Local project – as built
44

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

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