[PPT] - Innovative Processing for Stockpile Ash UKQAA Presentation 21st PowerPoint Presentation

SLIDE 1

Innovative Processing for Stockpile Ash

UKQAA Presentation

21st October 2015

SLIDE 2

Topics Covered

Material samples and characterisation
Wet storage studies
Initial laboratory processing studies
Initial concrete tests

SLIDE 3

Summary Project Flow Chart

Innovative Processing of Stockpile Fly Ash

Laboratory Conditioning Study Laboratory Scale Processing Use in Cementitious Systems Full-scale Tests Practical Guidelines Literature Review Characterisation Stockpile Fly Ash PHASE 0 PHASE 1 PHASE 2 PHASE 3 PHASE 4 PHASE 5

SLIDE 4

Materials Received to Date

Material received from 11 sources :

8 dry fly ashes
6 Stockpile fly ashes
8 Lagoon fly ashes

SLIDE 5

Material Characterisation

Property DFA 1 DFA 2 DFA 3 DFA 4 Fineness:% (45 µm) 33.8 8.1 5.7 19.1 LOI: % 8.3 3.3 9.9 14.4 Water Demand: % 97 96 100 109 Moisture Content: % 0.1 0.1 0.7 0.5 d10 2.5 1.6 0.9 2.7 d50 39.4 11.5 4.7 28.4 d90 199.4 62.7 153.4 132.4

Dry Fly Ashes

SLIDE 6

Material Characterisation

Property DFA 5 DFA 6 DFA 7 Fineness:% (45 µm) 18.5 18.3 21.2 LOI: % 13.6 3.9 6.8 Water Demand: % 104 100 100 Moisture Content: % 0.0 0.1 0.2 d10 2.6 2.7 2.6 d50 26.1 20.5 26.4 d90 81.5 82.0 103.1

Dry Fly Ashes

SLIDE 7

Material Characterisation

Dry Fly Ashes: Particle Size Distribution

1 2 3 4 5 6 0.1 1 10 100 1000 Volume (%) Particle diameter (µm) DFA 1 DFA 2 DFA 3 DFA 4 DFA 5 DFA 6 DFA 7

SLIDE 8

SEM Images

Dry Fly Ashes: x2000 Magnification DFA 1 DFA 2

SLIDE 9

Material Characterisation

Property SFA 1 SFA 2 SFA 3 SFA 4 Fineness:% (45 µm) 49.0 39.9 53.7 24.8 LOI: % 9.7 8.9 10.6 15.1 Water Demand: % 109 109 109 108 Moisture Content: % 12.7 21.1 17.7 15.8 d10 3.2 3.5 3.2 3.5 d50 31.3 38.7 30.9 28.9 d90 128.8 140.9 130.1 94.5

Stockpile Fly Ashes

SLIDE 10

Material Characterisation

Stockpile Fly Ashes: Particle Size Distribution

1 2 3 4 5 6 0.1 1 10 100 1000 Volumne (%) Particle Diameter (µm) SFA 1 SFA 2 SFA 3 SFA 4

SLIDE 11

SEM Images

Stockpile Fly Ashes: x2000 Magnification SFA 1 SFA 2

SLIDE 12

SEM Images

Stockpile Fly Ashes: x2000 Magnification SFA 3 SFA 4

SLIDE 13

Lime consumption by fly ash (BS EN 196-5)

MATERIALS QUANTITY Porland cement, g 15 Fly ash, g 5 De-ionized water, ml 100 Test temperature, °C 40 ± 2 Exposure period, days 8 and 15

SLIDE 14

Lime consumption by fly ash (BS EN 196-5)

2 4 6 8 10 12 14 16 18 20 35 45 55 65 75 85 95

Calcium oxide mmol Hydroxyl ion concentration mmol

Saturation…

Pass Fail

SLIDE 15

Material Characterisation

Dry Fly Ashes: Pozzolanic Activity

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 8 15 20 8 15 20 8 15 20 8 15 20 8 15 20 8 15 20 DFA 1 DFA 2 DFA 3 DFA 4 DFA 5 DFA 6

Calcium Oxide WRT Saturation Curve (%)

Pass

SLIDE 16

Stockpile Fly Ashes: Pozzolanic Activity

50.00
40.00
30.00
20.00
10.00

0.00 10.00 20.00 30.00 40.00 8 15 20 8 15 20 8 15 20 8 15 20 SFA 1 SFA 2 SFA 3 SFA 4

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

Material Characterisation

SLIDE 17

Wet Storage Studies

Dry Fly Ash moistened in laboratory at various

levels (10, 15 and 20%)

Stored in sealed plastic bags in drums
Kept in a controlled environment at 20 oC
Periodically removed and characterised

SLIDE 18

Wet Storage Studies

Property DFA 5 LS 10% Initial Moisture Content 0 day 1 day 7 day 1 month 3 months Fineness:% (45 µm) 18.5 19.5 19.4 24.7 43.2 LOI: % 13.6 14.3 13.9 15.5 14.4 Moisture Content: % 10.0 9.8 8.6 8.8 8.7 d10 2.6 2.7 2.8 3.9 4.8 d50 26.1 23.6 24.4 26.3 27.8 d90 81.5 75.6 78.0 80.3 78.8

DFA 5 LS Material Characteristics

SLIDE 19

Wet Storage Studies

DFA 5 LS Material Characteristics

Property DFA 5 LS 20% Initial Moisture Content 0 day 1 day 7 day 1 month 3 months Fineness:% (45 µm) 18.5 21.8 23.1 26.9 41.8 LOI: % 13.6 14.8 15.1 14.9 15.6 Moisture Content: % 20.0 16.2 15.9 16.1 16.0 d10 2.6 2.7 2.6 3.3 4.2 d50 26.1 27.5 25.7 27.6 28.7 d90 81.5 86.5 82.2 85.3 87.3

SLIDE 20

Wet Storage Studies

Property DFA 1 LS 10% Initial Moisture Content DFA 3 LS 10% Initial Moisture Content 0 day 3 month 6 month 0 day 3 month 6 month Fineness:% (45 µm) 33.8 54.5 56.5 5.7 30.5 33.2 LOI: % 8.3 9.0 8.7 5.5 5.9 6.7 Moisture Content: % 10.0 8.6 8.4 10.0 9.3 8.8 Water Requirement: % 97 108 110 100 105 107 d10 1.6 6.0

0.9

4.1 7.7 d50 11.9 40.7

6.1

24.3 32.3 d90 59.5 164.3

92.5

83.8 97.4

DFA 1 LS and DFA 3 LS Material Characteristics

SLIDE 21

Wet Storage Studies

Change in Moisture Content and Fineness During Storage DFA 4 LS

0.0 10.0 20.0 30.0 40.0 50.0 60.0

2 4 6 8 10 12 14 16 18 20

10 20 30 40 50 60 70 80 90 Fineness (45µm retention, %) Moisture Conent (%) Storage Duration (days) DFA 4 LS 10% MC DFA 4 LS 20% MC DFA 4 LS 10% Fineness DFA 4 LS 20% Fineness

SLIDE 22

Wet Storage Studies

Change in Moisture Content and Fineness During Storage DFA 5 LS

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 10 20 30 40 50 60 70 80 90 Fineness (45µm retained, %) Moisture Conent (%) Storage Duration (days) DFA 5 LS 10% MC DFA 5 LS 15% MC DFA 5 LS 20% MC DFA 5 LS 10% Fineness DFA 5 LS 15% Fineness DFA 5 LS 20% Fineness

SLIDE 23

Wet Storage Studies

Change in Moisture Content and Fineness During Storage DFA 1 and DFA 3

0.0 10.0 20.0 30.0 40.0 50.0 60.0 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 20 40 60 80 100 120 140 160 180 Fineness (Retained, %) Moisture Content (%) Storage Duration (days) DFA 1 LS 10% MC DFA 3 LS 10% MC DFA 1 LS 10% Fineness DFA 3 LS 10% Fineness

SLIDE 24

Wet Storage Studies

Particle Size Distribution of DFA 5 LS 10%

1 2 3 4 5 6 0.1 1 10 100 1000 Percentage Volume (%) Particle diameter (µm) Dry 1 day 7 day 1 Month 3 Months

SLIDE 25

Wet Storage Studies

Particle Size Distribution of DFA 5 LS 20%

1 2 3 4 5 6 0.1 1 10 100 1000 Percentage Volume (%) Particle diameter (µm) Dry 1 day 7 day 1 Month 3 Months

SLIDE 26

Wet Storage Studies

Particle Size Distribution of DFA 1 LS 10%

1 2 3 4 5 6 0.1 1 10 100 1000 Volume (%) Particle size distribution (µm) Dry 3 months 6 months

SLIDE 27

Wet Storage Studies

Change in Pozzolanic Activity During Storage DFA 1 LS and DFA 3 LS

43.2

23.0 38.4 37.3

74.5
52.9
17.1
1.6
74.5
56.5
23.0
1.8
5.9

23.1 31.4 37.3

74.5
35.3

12.2 22.9

95.6
49.5
11.8

3.8

110
100
90
80
70
60
50
40
30
20
10

10 20 30 40 50 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 DFA 1 DFA 1 LS-3 DFA 1 LS-6 DFA 3 DFA 3 LS-3 DFA 3 LS-6

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 28

Initial Conclusions

Around 20% of the initial moisture content of stored fly ash

was lost within the first 7 days beyond which the moisture content remains constant

Moisture is believed to become bound within the fly ash

and is not removed by oven drying at 105°C but is when testing for LOI at 975°C

The rapid decrease in moisture content did not coincide with

an immediate decrease in fineness due to agglomeration.

The decrease in fineness was noted to slow at 3-6 month

storage and further change was minor beyond 6 months

Wet Storage Studies

SLIDE 29

Initial Conclusions

Water requirement of the stored fly ash increased as

storage duration increased

Moistening and storing fly ash reduced lime consumption

and this effect increased with storage period

After 6 months, laboratory moistened and stored sample

results were found to be comparable to stockpile fly ash material

Similar effects were generally noted for the three moisture

contents tested, 10, 15 and 20%

Wet Storage Studies

SLIDE 30

Laboratory Processing Studies

Wet Fly Ash dried in oven at 105 oC then,

Ground in ball mill
Passed through an air jet mill
Passed through a 63 µm sieve
Thermally treated at 600 to 700 oC

SLIDE 31

Laboratory Processing Studies

Property SFA 1 SFA 1 SJM SFA 1 BM10 SFA 1 BM20 SFA 1 BM30 SFA 1 BM40 Fineness:% (45 µm) 49.0 7.4 12.1 4.11 2.7 1.3 LOI: % 9.7 9.7 9.9 9.6 9.9 9.8 Water Demand: % 109 100 100 100 99 100 Moisture Content: % 12.7 0.0 0.0 0.0 0.0 0.0 d10 3.2 2.0 1.9 1.7 2.0 1.8 d50 31.3 9.5 14.8 14.0 12.0 11.4 d90 128.8 31.8 61.1 49.8 41.0 37.4

Characterisation of Ground SFA 1 Material

SLIDE 32

Laboratory Processing Studies

Characterisation of Ground SFA 2 Material

Property SFA 2 SFA 2 BM10 SFA 2 BM20 SFA 2 BM30 SFA 2 BM40 Fineness:% (45 µm) 39.9 13.9 7.2 4.4 3.7 LOI: % 8.9 8.9 8.9 8.9 8.9 Water Demand: % 109 100 100 100 100 Moisture Content: % 21.1 0.0 0.0 0.0 0.0 d10 3.5 1.9 2.0 1.9 1.7 d50 38.7 17.8 15.1 13.9 12.1 d90 140.9 68.6 50.3 44.8 42.1

SLIDE 33

Laboratory Processing Studies

Particle size distribution of Ground SFA 1 Materials

10 20 30 40 50 60 70 80 90 100 1 10 100 1000 Passing (%) Particle diameter (µm) SFA 1 SFA 1 BM10 SFA BM20 SFA 1 BM30 SFA 1 BM40 SFA 1 SJM

SLIDE 34

Laboratory Processing Studies

Particle size distribution of Ground SFA 2 Materials

10 20 30 40 50 60 70 80 90 100

1 10 100 1000

Passing (%) Particle diameter (µm) SFA 2 SFA 2 BM10 SFA 2 BM20 SFA 2 BM30 SFA 2 BM40

SLIDE 35

SEM Images

Stockpile x2000 Magnification SFA 1 BM10 SFA 1 BM20 SFA 1

SLIDE 36

SEM Images

Stockpile x2000 Magnification SFA 1 BM30 SFA 1 SJM SFA 1

SLIDE 37

Bulk Oxide Composition

XRFS Bulk Oxide Composition Fly Ash Samples

Compound (%) SFA 1 <63µm SFA 1 BM20 SFA 2 <63µm SFA 2 BM20 DFA 1 LS-6 BM20 DFA 3 LS-6 BM20 SiO2 46.4 46.3 49.0 48.4 47.8 49.7 Al2O3 23.0 22.6 26.2 25.8 20.7 22.3 Fe2O3 9.3 9.3 9.6 9.1 8.5 7.6 CaO 5.0 5.3 2.4 2.5 5.7 4.2 K2O 2.3 2.3 2.8 2.8 2.3 2.7 Na2O 0.8 0.8 0.9 0.8 1.2 1.1 SO3 1.6 1.5 0.5 0.6 1.8 1.2 MgO 1.7 1.8 1.8 1.8 1.7 1.8 P2O5 0.6 0.6 0.4 0.4 0.6 0.5 TiO2 1.1 1.1 1.1 1.1 1.0 1.0

SLIDE 38

Laboratory Processing Studies

Pozzolanic Activity of Ground SFA 1 Materials

74.5
56.5
23.0
1.8

5.6 13.4 17.2

4.5

19.8 29.4

34.1

16.9 23.2 21.3

38.5

23.6 23.0 25.3

34.3

17.6 18.4 23.4

80
60
40
20

20 4 8 15 20 8 15 20 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 SFA 1 SFA 1 SJM SFA BM10 SFA 1 BM20 SFA 1 BM25 SFA 1 BM30

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 39

Laboratory Processing Studies

Pozzolanic Activity of Ground SFA 2 Materials

95.6
49.5
11.8

3.8

50.5

8.6 4.4 15.0

48.5

9.3 14.9 14.7

41.8

9.8 16.5 20.5

100
80
60
40
20

20 4 8 15 20 4 8 15 20 4 8 15 20 4 8 15 20 SFA 2 SFA 2 GM20 SFA 2 GM25 SFA 2 GM30

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 40

Activity Index (BS EN 450-1)

28-day Activity Index Pass/Fail SFA 1 74.3 Fail SFA 2 72.2 Fail SFA 1 BM20 83.7 Pass SFA 2 BM20 78.3 Pass

Grinding gives a 13% increase in activity index for SFA 1 and a 9% increase for SFA 2 at 28-days over unprocessed stockpile fly ashes

SLIDE 41

Laboratory Processing Studies

Property SFA 1 <63µm SFA 2 <63µm SFA 3 <63µm SFA 4 <63µm Fineness:% (45 µm) 9.2 6.4 8.6 8.5 LOI: % 8.9 6.0 7.4 15.0 Water Demand: % 104 100 103 104 Moisture Content: % 0.0 0.0 0.0 0.0 d10 6.5 3.0 5.4 4.6 d50 25.3 19.0 22.4 24.2 d90 56.8 52.3 50.8 57.0 Yield Obtained; % 40.0 31.0 20.4 47.4

Characterisation of Sieved Stockpile Material

SLIDE 42

Laboratory Processing Studies

Pozzolanic Activity of Sieved SFA 1 and SFA 2 Materials

56.5
23.0

4.7 19.2

49.5
11.8

3.7 15.8

60
50
40
30
20
10

10 20 8 15 8 15 8 15 8 15 SFA 1 SFA 1 <63μm SFA 2 SFA 2 <63μm

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 43

Laboratory Processing Studies

Thermally Treated Stockpile Material

2 4 6 8 10 12 LOI (%)

LOI after thermal treatment

SFA 1 LOI (%) SFA 2 LOI (%)

SLIDE 44

Laboratory Processing Studies

Pozzolanic Activity of Thermally Treated SFA 1 Materials

56.5
23.0
35.8
0.5
30.7
5.8
32.1
7.0
27.9
10.1
33.1

0.7

27.5
2.2
21.8
7.6
31.2
2.3
60
50
40
30
20
10

8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 SFA 1 TH600- 45 TH600- 60 TH700- 45 TH700- 60 TH600- 45-C/H TH600- 60-C/H TH700- 45-C/H TH700- 60-C/H

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 45

Laboratory Processing Studies

Pozzolanic Activity of Thermally Treated SFA 2 Materials

49.5
11.8
29.1

9.2

29.0

7.7

22.4

9.1

25.7

4.5

26.3

12.4

21.4

14.0

15.0

3.4

19.2

7.6

55
45
35
25
15
5

5 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 8 15 SFA 2 TH600- 45 TH600- 60 TH700- 45 TH700- 60 TH600- 45-C/H TH600- 60-C/H TH700- 45-C/H TH700- 60-C/H

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 46

Laboratory Processing Studies

Pozzolanic Activity of Ground and Thermally Treated Stockpile and Laboratory Stored Materials

74.5
52.9
17.1
1.6
60.2
13.0

12.8 14.6

62.5
23.0

19.8 20.4

74.5
35.3

12.2 22.9

67.7

9.5 18.5 26.6

58.6

3.3 20.4 18.5

95.6
49.5
11.8

3.8

69.3
11.6

15.1 23.6

67.8
11.9

14.4 14.5

120
100
80
60
40
20

20 40

4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 4 8 1520 Unprocessed BM20 BM+TH Unprocessed BM20 BM+TH Unprocessed BM20 BM+TH DFA 1 LS-6 DFA 3 LS-6 SFA 2

Calcium Oxide WRT Saturation Curve (%)

Pass Fail

SLIDE 47

Initial Conclusions

After 20 minutes grinding (ball mill) the fineness of fly

ash samples was found to be less than 12% retained regardless of initial fineness, beyond 20 minutes grinding is does not give further significant increases in fineness

Sieving using a 63µm mesh resulted in an increase in

all stockpiled samples fineness, to lower than 12% retained, and reduced LOI by a small degree in most cases however not in SFA 4

Sieving gave low useable yields of between 20-50%

from stockpile fly ash Laboratory Processing Studies

SLIDE 48

Initial Conclusions

Improvements in water requirement can be obtained

from grinding, sieving and thermal treatment

Grinding, sieving and thermal treatment all increased

lime consumption following the BS EN 196-5 test methods

The most effective furnace temperature and duration

for thermal treatment tested was found to be 600°C for 45 minutes allowing the fly ash to be heated and cooled with the furnace Laboratory Processing Studies

SLIDE 49

Previous Concrete Results (2005)

Stockpile and Lagoon Fly Ashes Concrete Compressive Strengths

y = 0.1229x + 26.132 R² = 0.8078 24 26 28 30 32 34 36 10 20 30 40 50 60 70 Particles < 10 μm, % Original 63 µm sieved Air-classified Ground L C A L C A L C A L C A 28 Days Compressive Strength (MPa)

w/c ratio 0.53

SLIDE 50

Concrete Mix Proportions

Mix Proportions (kg/m3)

Total Cement PFA % PC PFA Free Water Aggregate Sand W/C Ratio 20-10mm 10-5mm 350 30 245 105 175 805 405 650 0.5

All mixes included superplasticizing admixture ranging from 0.2% for ground stockpile fly ash up to 0.5% by mass of cement for unprocessed stockpile fly ash.

SLIDE 51

Admixture Required to Obtain S3 Slump

y = 0.3214x + 10.257 R² = 0.8624 5 10 15 20 25 30 10 20 30 40 50 60 Admixture (g) Fineness (% retained) Stockpile Beneficiated Stockpile Linear (All)

SLIDE 52

Concrete Strength

Ball Mill Grinding Concrete Compressive Strengths

19.6 20.4 19.8 17.2 18.9 19.8 20.7 19.0 28.4 26.3 23.4 25.6 24.3 24.1 27.5 24.8 38.1 39.0 37.2 38.5 37.3 36.6 40.6 39.1 42.7 45.8 47.9 45.6

0.00 10.00 20.00 30.00 40.00 50.00 60.00 Stockpile BM 10 BM 20 BM 30 Stockpile BM 10 BM 20 BM 30 SFA 1 SFA 2 Compressive Strength (MPa) 3-day Average 7-day Average 28-day Average 56-day Average

SLIDE 53

Initial Conclusions

Previous research suggests that the quantity of

particles less than 10 µm influence concrete strength

Admixture demand tends to correspond to the fineness
f fly ash following processing
There is no significant improvement noted in ground

stockpile samples over unprocessed samples until 28

r 56 days where improvements are up to 5 MPa

Concrete Studies

SLIDE 54

Research Plan for the Next 6 Months

Literature Review
Characterisation of test samples
Wet storage studies
Continuation of processing
Continuation of beneficiated fly ash concrete study
Planning of large-scale trial