This document summarizes a seminar presentation about bioconcrete as a sustainable construction material. Bioconcrete is a type of self-healing concrete that uses bacteria to seal cracks in concrete. It is composed of regular concrete ingredients along with bacterial spores and a nutrient. When cracks form, the spores activate, consume the nutrient, and precipitate minerals to fill the cracks. This extends the lifespan of concrete structures and reduces maintenance costs, providing environmental and economic benefits. The bacteria most suitable for this are spore-forming Bacillus species that can survive in the highly alkaline environment of concrete. Bioconcrete shows promise as a more sustainable alternative to traditional concrete.

1. Bioconcrete
as a SustainableConstruction Material
A seminarpresented by:
Asst. Prof. Muhammed Abbas Husain
December 2021
University of Samarra
College of Engineering
Department of Architecture Engineering

2. ‫الرحيم‬ ‫الرحمن‬ ‫الله‬ ‫بسم‬
(
‫عليم‬ ‫علم‬ ‫ذي‬ ‫كل‬ ‫وفوق‬
)
‫العظيم‬ ‫الله‬ ‫صدق‬

3. Contents
▪Meaning of Sustainability.
▪Impact of the Construction industry on Environment.
▪Needs for Sustainable Construction Industry.
▪Impact of Concrete on Environment.
▪Green Concrete.
▪Self-Healing Concrete.
▪Bioconcrete and its composition.
▪The Bacteria used in Bioconcrete.
▪Mechanism of Bacterial Healing.
▪Benefits of Bioconcrete.
▪Applicability of Bacterial Self-Healing.
▪Extended Applications of Bacterial Healing.

4. The Meaningof Sustainability
Sustainability refers to the ability of something to maintain (or sustain) itself
over time. It is used to describe maintaining the natural resources of the earth
for the current generation and for the next generations as well.

5. The ThreePillarsof Sustainability
Social sustainability: well-cared and healthy society.
Environment sustainability: Lowest impact to the environment.
Economic sustainability: Benefits between the sustainability and economy.
Without these three pillars the sustainability does not support itself.

6. Impact of Construction Industry on Environment
The main harmful impact of the construction industry:
▪ Consumes large amounts of natural resources.
▪ It is an energy-intensive products.
▪ Contributes to considerable carbon dioxide emission.
The amount of carbon dioxide emission from the building industry accounts
for about 47% of the total carbon dioxide emission in the UK.

7. Needs for Sustainable Construction Industry
Using of sustainable construction has become necessary as a result of:
▪ Increased levels of global pollution.
▪ Consumption of natural resources and energy.
▪ Continued global warming and climate change.
Main objectives of using sustainable construction:
➢ Using local construction materials to avoid transportation.
➢ Reducing the consumption of natural resources and energy.
➢ Reducing the waste and pollution that caused by the construction industry.
➢ Recycling the waste materials in the components of construction.
➢ Recycling and reusing the construction materials (life cycle sustainability).
➢ Increase the durability of the construction to reduce repairing and replacement.

8. Examplesof Sustainable ConstructionMaterials
(Environment-Friendlyor Eco-FriendlyMaterials)

9. Impactof Concrete on Environment
▪ Concrete is one of the most used building materials but it is a major
contributor to pollution through the production of cement.
▪ More than 25 billion tons of concrete are produced annually and use
about 3-4 billion tons of Portland cement worldwide per year.
▪ In addition to consuming natural materials and energy, in producing one
ton of Portland cement about one ton of carbon dioxide is released into
the environment.
▪ Calcination of limestone (the process of converting calcium carbonate
CaCO3 to calcium oxide CaO) releasing CO2 in the process.
CaCO3 + heat ⇒ CaO + CO2
▪ Approximately 40 percent of the CO2 emitted due to fuel combustion,
with the remaining 60 percent of the limestone during calcination.
▪ The cement industry is one of the most emitting source of gases which
results in about 10% of the total CO2 globally.

10. Green Concrete
▪ Green concrete is a concrete with more
sustainability..
▪ The word “green” refers to eco-friendly
system not to the color of concrete.
▪ The first green concrete had done by
Dr. WG. in Denmark in 1998.
▪ Main goals of green concrete:
➢ Reducing CO2 emissions and energy
consumption by replacing a ratio of
cement by another materials like fly ash.
➢ Reducing the consumption of natural
resources by using waste materials.
➢ Improving the properties and the
durability of the concrete.

11. Self-HealingConcrete
• Concrete self-healing is the process in which the material recovers itself
(repairing inner cracks) by an intrinsic (autogenous) or an extrinsic
(autonomous) process.
• Autogenous healing: produced by hydration of unhydrated cementitious
material particles or by precipitation of calcium carbonate (CaCO3).
• Autonomous healing: produced by reactions of agents added to the
concrete mix to produce self-healing. For examples: superabsorbent
polymers, microencapsulated sodium silicate, and bacteria.

12. Advantages of Self-Healing Concrete
• Any effort to improve the lifespan of
concrete structures will indirectly
improve the sustainability of the
environment.
• Ingress of water, chemicals, and gasses
cause leakage and degradation of
concrete and corrosion of embedded
steel reinforcement, affecting the
durability and service life of the
structure.
• Self-healing leads to more durable
concrete with longer lifespan thereby
resulting a more sustainable concrete.

13. Bioconcrete
(Bacteria-BasedSelf-HealingConcrete)
▪ Bioconcrete is a concrete that heals
itself using bacteria.
▪ Henk M. Jonkers, a microbiologist at
Delft University of Technology,
Netherlands, began working on it in
2006, when a concrete technologist
asked him if it possible to use bacteria
to make self-healing concrete.
▪ The first paper about the topic is
published by Jonkers et al. in 2010.
▪ This invention is a successful
combination of microbiology and civil
engineering – two sciences that are
unlikely collaborators at first glance.

14. Composition of Bioconcrete
▪ The bioconcrete is mixed just like regular concrete, but with an extra
ingredient: the bacteria (healing agents).
▪ The healing agents are mostly composed of:
➢ spores of Bacillus bacteria.
➢ Calcium lactate as a nutrient for the bacteria.
▪ The components are usually embedded in capsules (2 - 4 mm size)
to prevent interaction during mixing the concrete.

15. The Bacteria
▪ The bacteria used should be able to survive in an extremely alkaline
harsh environment (The pH value of concrete mis is up to 13).
▪ Jonkers et al. found that spore-producing bacteria (Bacillus) are the
only group of bacteria capable of surviving in such environment.
▪ Spores are inactive cells, with extremely thick cell walls which can
resist highly alkaline environment with fluctuations in temperature.
▪ The spores can stay intact for up to 200 years.
▪ The spores are activated when the food source and water are available.

16. Mechanismof BacterialHealing
▪ When the cracks in the concrete is initiated, they disintegrates
(break off) capsules and water begins to enter into a concrete cracks.
▪ Once the components of the capsules become in contact with the
water, the bacteria spores are activated.
▪ The activated bacteria start to consume the calcium lactate and convert
it to into insoluble calcium carbonate (limestone).
▪ The limestone expands to fill in the cracks and therefore rebuilds the
structure from the inside out, completely sealing the initial point
where the crack began.

17. Additional Healing
▪ The carbon dioxide reacts directly with calcium hydroxide which
available on the surface of the crack, forming an additional limestone.
Bacteria healing
Additional healing

18. Life Cycle of the Spore-ProducingBacteria
▪ After filling cracks are finished and the environment of the bacteria
no longer meets their living conditions, the active bacteria will return
to their dormant state and form spores again.

19. Benefits of Bioconcrete
▪ Reduces the costs of concrete
repair and maintenance.
▪ Well-suited for structures that are
exposed to weathering, as well as
points that are difficult to access
for repair workers.
▪ Extends the durability and lifespan
of concrete structures.
▪ Improves the mechanical
properties of the concrete and
enhance its strength.
▪ Improves the sustainability of the
concrete.

20. Applicabilityof BacterialSelf-Healing
▪ Bacteria can heal cracks up to 1 mm wide.
▪ Complete healing takes up to 3 – 4 weeks.
▪ The amount of 15 kg of healing-agents per one cubic meter of cement
mortar gives efficient recovery.
▪ Currently the healing-agents cost (in Europe) around 130 dollars per
a cubic meter of bioconcrete, but a new method of encapsulating are
currently investigated which will reduce the cost of healing-agents to
be about 20 – 25 dollars.

21. Extended Applications of BacterialSelf-Healing
▪ The applications of bacterial healing are extended into two other mixtures:
➢ Liquid repair system.
➢ Repair mortar.
▪ In self-healing concrete, bacterial content is integrated during construction,
while the repair mortar and liquid system only come into play when acute
damage has occurred on concrete elements.

22. Self-healing concrete appears a promising,
sustainable alternative for extending the service
life of new structures, lowering maintenance costs
and avoiding complicated repairs.
Dr. M. S. Moreno
University of Cordoba

23. Thank you