self-healing concrete: ready for the market? - betonica healing... · challenge the future 1...
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1Challenge the future
Self-healing concrete:Ready for the market?
Henk Jonkers, Renee Mors, Annegreeth Lameijer Symone KokDelft University of Technology [email protected] [email protected]
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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