Bio-concrete
Bio-concrete, also known as self-healing concrete, is a type of concrete that contains bacteria or other microorganisms that can precipitate calcium carbonate (CaCO3) to fill cracks and heal the concrete. This process is similar to how natural materials like seashells and bones form. Bio-concrete is still under development, but it has the potential to revolutionize the construction industry by reducing the need for repairs and extending the lifespan of concrete structures.
Concrete, one of the most
widely used building materials, is essential in many industries. Buildings,
dams, storage tanks, seaports, highways, bridges, tunnels, subways, and other
infrastructure have all been built using it extensively. Cement, coarse and
fine aggregate, and water are the essential ingredients of concrete. The most
crucial component of concrete is cement. It fills the spaces between coarse and
fine particles and binds the aggregates. Concrete is the material of choice for
many applications due to its high compressive strength, availability,
durability, compatibility with reinforcement bars, affordability, ease of
preparation, and flexibility to be cast in the necessary shapes and sizes.
Despite concrete’s
advantages, it has a high tendency to produce fractures allowing aggressive
chemicals to infiltrate into the structure. Cracks are one of the main causes
of concrete deterioration and loss in durability. Cracks can be developed in
both plastic and hardened states. Formwork movement, plastic settlement and
plastic shrinkage due to rapid loss of water from the concrete surface result
in crack formation during the plastic state, whereas weathering, drying
shrinkage, thermal stress, error in design and detailing, chemical reaction,
constant overload and external load contribute to crack formation in hardened
state.
Concrete is one of the
most extensively used construction materials and has a high potential to create
cracks. These cracks lead to considerable reduction in concrete service life
and high replacement costs. Although it is not possible to prevent crack creation,
many sorts of treatments are in place to heal the cracks. It has been
established that some of the current concrete treatment methods such as the
application of chemicals and polymers are a source of health and environmental
dangers, and more significantly, they are effective only in the short term.
Thus, treatment solutions that are ecologically friendly and long-lasting are
in great demand. A microbial self-healing technique is characterized by its
potential for long lasting, fast and active crack repair, while also being
environmentally friendly. Furthermore, the microbial self-healing approach
surpasses the other treatment strategies due to the efficient bonding capacity
and compatibility with concrete compositions.
Bio-concrete is a
revolutionary new building material that has the potential to revolutionize the
construction industry. This innovative material is created by combining
bacteria and concrete, resulting in a product that is both environmentally
friendly and incredibly strong.
Bio-concrete is created
by introducing a special type of bacteria into the concrete mixture. This
bacteria, known as Sporosarcina pasteurii, feeds on calcium lactate and
produces calcium carbonate, which is a key component of concrete. As the
bacteria feeds, it produces calcium carbonate, which strengthens the concrete
and makes it more resistant to cracking and other damage. In addition, the
calcium carbonate produced by the bacteria also helps to absorb and store
carbon dioxide, making bio-concrete a more sustainable and environmentally
friendly building material.
Bio-concrete is an
exciting new development in the construction industry and has the potential to
revolutionize the way we build. Not only is it stronger and more durable than
traditional concrete, but it is also more sustainable and environmentally friendly.
With its unique properties, bio-concrete promises to be an important part of
the future of construction.
- -
Bio-concrete is a type of concrete that
uses bacteria to create a self-healing material.
- - This material is created by adding a
special type of bacteria to the concrete mix, which produces calcium carbonate
when it comes into contact with water.
- -
This calcium carbonate acts as a filler,
filling in any cracks or holes in the concrete and making it stronger and more
durable.
- - Bio-concrete is more environmentally
friendly than traditional concrete, as it does not require the use of large
amounts of energy or resources to produce.
- - It also has a longer lifespan, as it is
able to repair itself over time.
Overview
of microorganisms and nutrients which have been used to produce calcium
carbonate in concrete matrix
Microorganism |
Nutrient |
|
Bacillus pseudofirmus |
Calcium lactate,
calcium glutamate, yeast extract and peptone |
|
Bacillus pseudofirmus |
Calcium lactate,
calcium acetate, yeast extract and peptone |
|
Bacillus sphaericus |
Urea and calcium chloride |
|
S. pasteurii |
Urea,
calcium nitrate and calcium chloride |
|
Bacillus amyloliquefaciens |
Urea, calcium acetate yeast extract and glucose |
|
Diaphorobacter nitroreducens |
Urea, calcium formate, calcium nitrate and yeast extract |
|
Sporosarcina soli |
Urea and calcium chloride |
Application of bio self-healing methodology commends itself over existing treatment methods due to efficient bonding capacity, compatibility with concrete compositions and sustainability. It is capable of filling deep microcracks as well as restricting crack formation. This can reduce inspection work and maintenance expenses (Jonkers et al. 2010; Wang et al., 2012a). Moreover, it reduces carbon dioxide emission due to the decrease of cement production (De Muynck et al., 2008a; De Muynck et al., 2008b; Berenjian et al. 2012). Reduction in porosity of structure, rendering the concrete watertight, good compatibility between precipitated calcium carbonate and concrete compositions and favourable thermal expansion are the other advantages of this procedure. Bio self-healing treatment delivers safer, more sustainable, more long-standing and more inexpensive construction materials. Therefore, mixing healing agent with cement and other materials during casting makes this method a potential strategy as compared to the standard treatment procedures.
Key Points
- ·
Sustainable and eco-friendly
- · Strong bonding capacity, compatibility
with concrete compositions, and sustainability
- · Fill deep micro-cracks and prevent cracks
from spreading
- ·
Reducing labor and upkeep costs
- ·
Reducing cement production, carbon dioxide
emissions are reduced
- ·
The addition of bacteria significantly
improves concrete's properties
- ·
Adding bacteria significantly increases
compressive and split tensile strength
- ·
Bacteria generate calcium carbonate, which
seals and fills cracks, repairing damage
- ·
Bio concrete, when combined with sand,
reduces voids and increases packing density
- ·
Destructive and non-destructive tests show
that 10% bacteria addition yields optimal results
- ·
Bio concrete has a 15% greater compressive
strength than ordinary concrete, 30% more flexural strength, and the ability to
withstand larger strains, and preventing earthquakes
References:
Seifan, M., Samani, A.K. & Berenjian, A. Bioconcrete: next
generation of self-healing concrete. Appl Microbiol Biotechnol 100,
2591–2602 (2016).
Jonkers
HM, Thijssen A, Muyzer G, Copuroglu O, Schlangen E (2010) Application of
bacteria as self-healing agent for the development of sustainable concrete.
Ecol Eng 36:230–235
De Muynck W, Debrouwer D, De Belie N,
Verstraete W (2008a) Bacterial carbonate precipitation improves the durability
of cementitious materials. Cement Concrete Res 38:1005–1014
Berenjian
A, Chan N, Malmiri HJ (2012) Volatile organic compounds removal methods: a
review. Am J Biochem Biotechnol 8:220–229