Self-healing concrete: Ready for the market? - Betonica Healing... · Challenge the future 1...

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Self-healing concrete:Ready for the market?

Henk Jonkers, Renee Mors, Annegreeth Lameijer Symone KokDelft University of Technology Corbionh.m.jonkers@tudelft.nl s.kok@corbion.com

a.a.lameijer@tudelft.nl

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1. Concrete & self-healing mechanisms

2. Bacteria-based self-healing concrete

3. Practical applications

CEG – Structural Engineering - Materials & Environment - Sustainability Group

Topics overview:

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1. Concrete: most used construction material

CementSand

Gravel Water

Chemicals(performance enhancers)

Relatively cheap!: +/- 80 Euro / m3

Concrete

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‘Designed’ damage No strength loss but decreases durability (service life!)

Damage contours of reinforced concrete with loadingwww.ansys.com

Typically:Micro crack formation

Concrete problems

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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→ Ingress of aggressive chemicals

→ Degrada�on of concrete matrix

→ Risk of reinforcement corrosion

Needed: Self-healing mechanism resulting

in Sealing of cracks, reducing permeability

‘Designed’ damage No strength loss but decreases durability (service life!)

CEG – Structural Engineering - Materials & Environment - Sustainability Group

Concrete problems

6Challenge the futureCEG – Structural Engineering - Materials & Environment - Sustainability Group

1. Concrete & self-healing mechanisms

→ Permeability decreasing / crack sealing systemsExamples of self-healing systems investigated by TUD:

Wiktor & Jonkers

1. (Encapsulated) cements, expanding agents

3. Encapsulated chemical agents

4. Bio-mineral producing bacteria

2. Fiber reinforced cementitious composites

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2. Limestone-producing bacteria

How to make concrete self-healing with bacteria?→ include limestone-producing bacteria!

Locations:1. Chiprana, Spain (dessert crusts)

2. Playa, Spain (carbonate / gypsum rock)

3. Wadi Natrun, Egypt (alkaline lake)

4. Kulunda lakes, Siberia (alkaline lakes) 3. Wadi Natrun, Egypt pH ~ 10

4. Altai Steppe, Siberia pH ~ 102. Playa, rock 1. Chiprana, crust

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Endospore

Wadi Natrun, Egypt pH ~ 10

Playa, rock

Alkali-resistant

spore-forming bacteria

1. > 50 years viable

2. Concrete compatible

Endolithic communities

Soda-lake communities

2. Limestone-producing bacteria

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+

Ca(C3H5O3)2 + 6 O2 >>> CaCO3 + 5 CO2 + 5 H2O

(Increased calcite productionfrom concrete matrix Portlandite:) Ca(OH)2

2. Limestone-producing bacteria

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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Two-component ‘self-healing agent’:

1. Bacteria (catalyst)

2. Mineral precursor compound (chemical / 'food')

→ Packing of agents in particles

Reservoir for healing agents (bacteria + chemicals)

Bacteria food

CEG – Structural Engineering - Materials & Environment - Sustainability Group

2. Limestone-producing bacteria

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2. Limestone-producing bacteria

Llim Cicatrisation « naturelle » < 180µmCaCO3

Massive CaCO3precipitation

325 µm

Crack width healing limit Llim : Bacterial concrete < 460 µm

Quantification of crack-healing

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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Two-component self-healing agent:

1. Bacterial spores (powder)

2. Mineral precursor compound (powder)

Powder compression + coating (concrete compatible)

1. Strong

2. Good concrete binding properties

Tablets: 2nd generationHealing agent

Expensive

2. Limestone-producing bacteria

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New concepts TUD/Corbion3rd generation healing agent:

Bio-based / strong / large scale - economical

1. Bacteria

2. Food (Puracal)

3. Bacterial growth agent

4. Encapsulation Matrix (Puralact)

Initial products

PLA-coatingSpores / Nutrients /

CaLactate

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PLA-based healing agent

Computer tomography (CT)-scan:PLA-coated particle in (Portland) cement paste

t=0 t=24h t=7d

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Potential of limestone producing bacteria for:

1. Repair materials:

→ Impregnation system

→ Repair mortar

2. Self-healing concrete

3. Practical applications

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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1. Development / application of liquid impregnation system

→ Micro-crack healing / matrix densification

→ Leakage proving /

increase durability

e.g. frost/thaw scaling

→ Impregnation system

3. Practical applications

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Bacterial CaCO3 formation in impregnation system

3. Practical applications

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First aid emergency station 'Paviljoen Galder', Breda

3. Practical applications

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2. Development of fiber-mortar based repair system

→ Repair / retrofitting larger damages

→ Improved compatibility / durability

Thermal changes /Delamination Drying shrinkage

→ Repair mortar

3. Practical applications

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3. Practical applications

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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Self-healing concrete: irrigation canals in Ecuador

3. Practical applications

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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3. Practical applications

Cruzsacha Canal:Length = 19 kmHeight = 4100 to 3800 mDaily temp = 5 to 15C

Canal cross section

Landscape around Poalo

15 15

100

??

?100 cm

Irrigation canals in Ecuador

CEG – Structural Engineering - Materials & Environment - Sustainability Group

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Conclusions

1. Several concepts for self-healing concrete are being developed

2. Limestone-producing bacteria can make concrete self-healing

3. Large scale (economical) production in progress

4. Various full scale outdoors applications under way

CEG – Structural Engineering - Materials & Environment - Sustainability Group