Geopolymer Cements: Resistance-Engineered Sewer

Infrastructure for Longevity using Innovative, Energy-efficient,

Synthesis Techniques (RESILIENT)

Wil V. Srubar III, PhD, University of Colorado Boulder

Claire White, PhD, Princeton UniversityTeam Members: Mohammad Matar, Christine Pu, Xu Chen, and Kai Gong

Total Project Cost: $1.2M

Length 24 mo.

Solving biogenic acid-induced concrete corrosion, cement-related CO2 emissions, and life-

cycle cost with performance-enhanced alkali-activated metakaolin

Sewer Systems in the United States

Problem: Biogenic Sulfuric Acid Degradation of OPC Concrete via Microbial-Induced Concrete Corrosion

Proposed Solution: Low-Calcium Alkali-Activated Cement

(i.e., Geopolymer) Concrete

SOB

H2SO4 + OPC ® Gypsum (CaSO4)

$13.8B Per Year on MICC

Sewer Systems in the United States

Conventional Materials Used in Sewer Infrastructure

Alkali-Activated

Metakaolin

(i.e., Geopolymer)

Coating

Our Solution:

Project Objectives:

To engineer a geopolymer cement that exhibits 80% reductions in steady-state biodeterioration rates

compared to OPC concrete (from ~5 mm year to ~1 mm year), which will extend the service life of concrete

sewer infrastructure ~5X (250 Years) and will yield reductions in total life cycle environmental (i.e., embodied

energy and embodied carbon) costs of mitigating biogenic sulfuric acid degradation by 75%.

The Team

‣ Specializes in integrating biology, polymer science, and cement chemistry for innovative,

responsive material technologies; Previous

NSF Award on Acid Resistant Geopolymers

‣ Researchers: Xu Chen, Mohammad Matar

3

University of Colorado Boulder Princeton University

PI: Wil V. Srubar III, Ph.D. Co-PI: Claire E. White, Ph.D.

‣ Specializes in the complex and heterogeneous sub-micron structures and processes in

conventional and alternative cements using a

combined simulation-experiment approach

‣ Researchers: Kai Gong, Christine Pu

Project Objectives

4

Cation 1

Cation 2

‣ Goal #1: Establish benchmarks for sulfuric acid resistance and desirable

mechanical properties

‣ Goal #2: Demonstrate superiority of low-calcium geopolymer binders for sulfuric

acid resistance

‣ Goal #3: Produce synthetic metakaolin on

the benchtop to address

limited geographic

availability

‣ Goal #4: Maximize sulfuric acid resistance through

novel cation additives;

strongly bound cations that

stabilize geopolymer

framework

4

Cation 1 Cation 2

Project Objectives

5

Cation 1

Cation 2

Cation 1 Cation 2

4

‣ Goal #1: Establish benchmarks for sulfuric acid resistance and desirable

mechanical properties

‣ Goal #2: Demonstrate superiority of low-calcium geopolymer binders for sulfuric

acid resistance

‣ Goal #3: Address limited geographic availability of

metakaolin through

creation of synthetic

metakaolin

‣ Goal #4: Maximize sulfuric acid resistance through

novel cation additives;

strongly bound cations that

stabilize geopolymer

framework

Project Objectives

6

‣ Goal #5: Improve economic viability and energy efficient manufacturability through abiotic and biotic

seeding agents; seeding agents should increase

reaction kinetics and enable reduced alkali content

and accelerate ambient-temperature curing

‣ Goal #6: Substantiate improved economic and environmental

viability through lifecycle cost

analysis and lifecycle assessment

5

Nano-Seed

#1

Nano-Seed

#2

Nano-Seed

#3

Nano-Seed

#4

Project Objectives

7

‣ Goal #5: Improve economic viability and energy efficient manufacturability through abiotic and biotic

seeding agents; seeding agents should increase

reaction kinetics and enable reduced alkali content

and accelerate ambient-temperature curing

‣ Goal #6: Substantiate improved economic and environmental

viability through lifecycle cost

analysis and lifecycle assessment

5

Nano-Seed

#1

Nano-Seed

#2

Nano-Seed

#3

Nano-Seed

#4

Results: Benchmarking

8

OPC Samples Geopolymers>15 MPa

Results: Benchmarking

9

0

0.1

0.2

0.3

0.4

0.5

0.6

Type I/II - w/c

=0.4

Type I/II - w/c

=0.5

Type II/V - w/c

=0.4

Type II/V - w/c

=0.5

2 3 6 7

Corr

osi

on

Dep

th (

mm

)

H2SO4 Exposure: Sample Corrosion Depth @ 7 Days

Geopolymer Mix ID

All three (Mix ID

2, 3, and 6)

moved forward

for cation

enhancement

studies

Results: Cation Binding Energies

10

= Selected for

Further Study

Based on

Performance and

Cost Considerations

Results: Improved Sulfuric Acid Resistance

11

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

2 2-1a 2-1b 2-2a 2-2b 2-3a 2-3b 2-4a 2-4b

Co

rro

sio

n D

ep

th (

mm

)

Mix ID

Benchmark

-95%

90%

43%

-94%

-99%

100%

-70%

135%

142%

Nomenclature: 2-1aGeopolymer Mix ID

Cation Dosage

Cation ID

Results: Improved Sulfuric Acid Resistance

12

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

3 3-1c 3-2c 3-3c 3- 4cC

orr

osi

on

Dep

th (

mm

)

Mix ID

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

2 2-1a 2-1b 2-2a 2-2b 2-3a 2-3b 2-4a 2-4b

Co

rro

sio

n D

ep

th (

mm

)

Mix ID

-95%

86%

90%

89%

43%

-94%

-99%

-97%

100%

-70%

135%

142%

125%

148%

Results: Improved Sulfuric Acid Resistance

13

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

3 3-1c 3-2c 3-3c 3- 4cC

orr

osi

on

Dep

th (

mm

)

Mix ID

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

2 2-1a 2-1b 2-2a 2-2b 2-3a 2-3b 2-4a 2-4b

Co

rro

sio

n D

ep

th (

mm

)

Mix ID

0

0.1

0.2

0.3

0.4

0.5

0.6

Type

I/II -

w/c

=0.4

6 6-1a 6-1b 6-2a 6-2b 6-3a 6-3b 6-4a 6-4b

Co

rro

sio

n D

epth

(m

m)

Mix ID

-95%

86%

90%

89%

43%

-94%

-99%

-97%

100%

-70%

135%

142%

125%

148%

187%

107%

36%

-99%

-98%

138%

-49%

121%

85%

Main Takeaway: Geopolymer Mix #2 and #3 + Cation #2

Results: Best Performing Mix Selection

14

Overall

Pass/FailGeopolymer Mix ID Acid Resistance Compression Setting Time Porosity

Pass 2 Pass Pass Pass Pass

Fail 2-1a Fail Pass Pass Fail

Fail 2-1b Fail Pass Pass Fail

Pass 2-2a Pass Pass Pass Pass

Pass 2-2b Pass Pass Pass Pass

Fail 2-3a Fail Pass Pass Pass

Fail 2-3b Fail Pass Pass Pass

Fail 2-4a Fail Pass Pass Pass

Fail 2-4b Fail Pass Pass Pass

Fail 3 Fail Pass Pass Pass

Fail 3-1c Fail Pass Pass Pass

Pass 3-2c Pass Pass Pass Pass

Fail 3-3c 125% Pass Pass Pass

Fail 3-4c 148% Pass Pass Pass

Fail 6 Fail Pass Fail Pass

Fail 6-1a Fail Pass Pass Pass

Fail 6-1b Fail Pass Pass Pass

Fail 6-2a Pass Pass Fail Pass

Fail 6-2b Pass Pass Fail Pass

Fail 6-3a Fail Pass Fail Pass

Fail 6-3b Fail Pass Pass Pass

Fail 6-4a Fail Pass Fail Pass

Fail 6-4b Fail Pass Fail Pass

Results: Initial Cost Analysis of Best-Performing Mixes

15

0

20

40

60

80

100

120

140

OPC Raven 405 GeopolymerPipe

GeopolymerCoating

Co

st

($/L

F)

Upfront Cost Comparison

Labor Cement pasteRaven 405 MetakaolinWater Cation additiveActivator

Results: Initial Cost Analysis of Best-Performing Mixes

16

0

20

40

60

80

100

120

140

OPC Raven 405 GeopolymerPipe

GeopolymerCoating

Co

st

($/L

F)

Upfront Cost Comparison

Labor Cement pasteRaven 405 MetakaolinWater Cation additiveActivator

0.0

0.5

1.0

1.5

2.0

2.5

OPC Raven 405 GeopolymerPipe

GeopolymerCoating

Co

st

($/L

F/Y

ea

r)

Cost per Year Comparison

Labor Cement pasteRaven 405 MetakaolinWater Cation additiveActivator

50

ye

ars

50

ye

ars

25

0 y

ea

rs

85

ye

ars

Challenges and Risks

‣ Our product needs to be as cost effective and easy to implement as portland cement

‣ We must ensure supply chain sustainability (e.g., geographic availability of metakaolin)‣ We aim to address these challenges and risks in Phase II of the project

Minimize

Cost

Consumer

Education

Application-based

Constraints

New Product

Integration

Potential Partnerships

18Insert Presentation NameNovember 6, 2020

Summary

19Insert Presentation NameNovember 6, 2020

‣ Geopolymer cement is our solution to biogenic sulfuric acid sewer corrosion– Extended lifespan, lower lifecycle cost, and reduced environmental impact

‣ Current work demonstrates superior acid resistance of cation-dosed geopolymer cement

‣ Future work will address:– Improving technical performance (Goal #5)

– Expanding geographic availability (Goal #2)

– Establishing partnerships with relevant companies to bring this technology to market (T2M).

Benchmark

performance

Enhance acid

resistance with metal

cations

Create synthetic

metakaolin

Add abiotic and

biotic additives

Compute life cycle

economic and

environmental costs