1 www.carboncure.com Simply Better Concrete 1

Fifth International Conference on Accelerated Carbonation for Environmental and Material Engineering (ACEME 2015) June 24, 2015

Carbon Upcycling to Improve Ready-Mixed Concrete Sean Monkman1,Mark MacDonald1, Paul Sandberg1, Doug Hooton2

1 CarbonCure Technologies 2 University of Toronto, Department of Civil Engineering

2 www.carboncure.com Simply Better Concrete

is the most abundant man-made material on the planet and makes up about 50% by mass of all materials produced globally.

Materials and the Environment, 2nd Ed, by M.F. Ashby, 2012

CONCRETE

3 www.carboncure.com Simply Better Concrete

0

1

2

3

4

5

6

1990 2000 2010 2020 2030 2040 2050

Gt

Cem

ent

Year

CEMENT is the most important component of concrete and is in ever increasing demand

USGS/IEA

China

Other developing countries

India

OECD, industrial nations

3

4 www.carboncure.com Simply Better Concrete

A SOBERING LOOK AT DEMAND

4

0

1

2

3

4

5

6

7

USA (1901-2000)

China (2011-2013)

Cem

ent

cons

umpt

ion

(Gt)

China used 47% more cement between 2011 and 2013 than the United States used in the entire 20th century.

Making the Modern World: Materials and Dematerialization, Vaclav Smil

5 www.carboncure.com Simply Better Concrete

CO2 EMISSIONS

5 Damtoft et al, (2008). Cement and Concrete Research, 38(2), 115-127

are a byproduct of cement production and total about 5% of the total annual global. One tonne of cement

clinker results in about 865 kg of CO2 emitted.

6 www.carboncure.com Simply Better Concrete

Carbon solution: upcycle CO2

6

Limestone CaCO3

CO2 permanently mineralized within concrete

Concrete

Add aggregates & water

CaCO3 bound within

CO2

Cement CaO

7 www.carboncure.com Simply Better Concrete 7

Carbon dioxide can react with cement

Precipitation (CO2 Storage)

Ca+2(aq) + CO3

-2(aq) ↔ CaCO3 (s)

CO2 Dissociation (CO3

-2 Supply)

CO2 (g) ↔ CO2 (aq)

CO2 (aq) + H2O ↔ H2CO3 (aq)

H2CO3 (aq) ↔ HCO3- (aq) + H+

HCO3- (aq) ↔ CO3

-2 (aq) + H+

Dissolution (Ca2+ Supply)

3CaO·SiO2 + 3H2O ↔ 3Ca2+ + SiO20 + 6OH-

2CaO·SiO2 + 2H2O ↔ 2Ca2+ + SiO20 + 4OH-

Ca(OH)2 + H2O ↔ Ca2+ + 2OH- + H2O

=

+

Cement + water + CO2 → calcium carbonate

8 www.carboncure.com Simply Better Concrete 8

Gas system meters CO2

9 www.carboncure.com Simply Better Concrete 9

Inject CO2 into the concrete as it mixes

10 www.carboncure.com Simply Better Concrete 10

Trial summary

o  Workability, temperature, isothermal calorimetry

o  Compressive strength (1, 3, 7, 28, 56, 91 days),

o  Resistivity

Truck 1 Three sequential doses of CO2 after batching

Truck 2 One dose of CO2 during batching

11 www.carboncure.com Simply Better Concrete

Trial outline

11

Sample Code Condition CO2 dose

(%bwc)

Age at injection

(min)

Slump (inches)

Mix Temperature

(°C)

801 Control -  -  3.5 22.4

802 CO2 0.10 27 3.0 24.0

803 CO2 0.30 43 2.5 24.7

804 CO2 0.60 52 1.5 27.3

805 CO2 0.30 0 3.0 23.3

•  Workability was decreasing •  Temperature was increasing … attributable to the hydration time or CO2 addition?

12 www.carboncure.com Simply Better Concrete 12

Calorimetry – Power

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2 6 10 14 18 22

Nor

mal

ized

Pow

er (a

.u.)

Time After Mixing (hours)

Control 801

CO2 802

CO2 803

CO2 804

CO2 805

13 www.carboncure.com Simply Better Concrete 13

Serial dose – Early strength

1 da

y

3 da

y

7 da

y

99%

106%

108%

107%

112%

109%

106%

111%

115%

0

1000

2000

3000

4000

0

5

10

15

20

25

30

Control CO2 - 1 CO2 - 2 CO2 - 3

Com

pres

ive

Stre

ngth

(psi

)

Com

pres

sive

Str

engt

h (M

Pa)

Batch

14 www.carboncure.com Simply Better Concrete 14

Serial dose – Late strength

28 d

ay

56 d

ay

91 d

ay

104%

110%

107%

85%

116%

111%

103%

106%

107%

0

1000

2000

3000

4000

5000

6000

0

5

10

15

20

25

30

35

40

45

Control CO2 - 1 CO2 - 2 CO2 - 3

Com

pres

ive

Stre

ngth

(psi

)

Com

pres

sive

Str

engt

h (M

Pa)

Batch

15 www.carboncure.com Simply Better Concrete 15

Strength - CO2 during batching

114%

126%

121%

115%

118%

0

1000

2000

3000

4000

5000

6000

0

5

10

15

20

25

30

35

40

45

1 day 3 day 7 day 28 day 56 day

Com

pres

sive

Str

engt

h (p

si)

Com

pres

sive

Str

engt

h (M

Pa)

Test Age

16 www.carboncure.com Simply Better Concrete

Strength benefit conclusions

16

•  Best results observed when CO2 added during batching •  Resistivity results assured no change to chloride risk

Age (days)

1 3 7 28 56 91

0801 Control 100% 100% 100% 100% 100% 100%

0802 0.10% CO2 99% 107% 106% 104% 85% 103%

0803 0.30% CO2 106% 112% 111% 110% 116% 106%

0804 0.6% CO2 108% 109% 115% 107% 111% 107%

0805 0.30% CO2 114% 126% 121% 115% 118% 115%

17 www.carboncure.com Simply Better Concrete

Mechanism

In-situ formation of nano-CaCO3 consistent with ex-situ nano-calcite addition

18 www.carboncure.com Simply Better Concrete 18

Environmental Impact •  Doses are small, but industry is huge •  A consistent strength benefit allows

for increased SCM usage thereby lowering the carbon footprint of the concrete mix design.

19 www.carboncure.com Simply Better Concrete

Further work - Durability Study

19

•  Strength •  Compressive and flexural

•  Exposure •  Freeze-thaw durability, salt

scaling •  Chloride Permeability •  RCPT, bulk diffusion test

•  Shrinkage •  Service life carbonation

testing •  Abrasion testing

20 www.carboncure.com Simply Better Concrete 20

Thank You Sean Monkman VP Technology Development smonkman@carboncure.com @carboncure