It was prepare during a seminar in my B.tech

1. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
SELF HEALING CONCRETE
Introduction
The concept of self-healing concrete (SHC) that
happens over time (autogenic) has been
observed in many old structures which have
remained standing for long periods of time in
spite of the fact that they have limited
maintenance.

2. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
Self-healing concrete is a product that will biologically produce
limestone to heal cracks that appear on the surface of concrete
structures.
Specially selected types of the bacteria genus Bacillus, along with
a calcium-based nutrient known as calcium lactate, and nitrogen
and phosphorus, are added to the ingredients of the concrete
when it is being mixed.
These self-healing agents can lie dormant within the concrete for
up to 200 years.
BIO-CONCRETE

3. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
when a concrete structure is damaged and water starts to seep
through the cracks that appear in the concrete, the spores of the
bacteria germinate on contact with the water and nutrients.
The bacteria gets activated & starts to feed on the calcium lactate.
As the bacteria feeds on, Oxygen is consumed and the soluble
calcium lactate is converted to insoluble limestone.
The limestone solidifies on the cracked surface, thereby sealing it
up.

4. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
The consumption of oxygen during the bacterial conversion of
calcium lactate to limestone has an additional advantage.
Oxygen is an essential element in the process of corrosion of
steel and when the bacterial activity has consumed it all it
increases the durability of steel reinforced concrete constructions.

5. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
The two self-healing agent parts:
 Bacterial spores.
 Calcium lactate-based nutrients.
are introduced to the concrete within separate expanded clay
pellets 2-4 mm wide, which ensure that the agents will not be
activated during the cement-mixing process.
Only when cracks open up the pellets and incoming water brings
the calcium lactate into contact with the bacteria do these become
activated.

6. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
Comparison of some aspects
Safety:
1. Cracks are closed with no extra costs.
2. General safety of a particular construction is increased.
3. Conducted Researches showed that concrete gains about
25% of its original strength in the healed spot which more than
the 15% gained back when the crack is sealed by current
methods.
Cost:
1. It is obvious that the initial cost of construction using SHC is
higher, however, on the long-term, durable concrete is much
more cost-efficient due to the low cost of maintenance.

7. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
Durability:
1. Research and experimentation bacteria-based SHC is denser
and more durable than concrete.
Availability:
1. It is still under development.
2. Used on a limited scale and still not commercially wide-spread.
3. Main obstacles are cost and production.

8. ST. ANDREWS INSTITUTE OF
TECHNOLOGY & MANAGEMENT
Effects on Architecture & Design: Architects’ main task is to
foresee the upcoming needs and the current ones to design and
construct a useful, aesthetic and more importantly, highly-flexible
buildings in order to be change function easily.
Environmental impact: Cement industry is one of the main
producers of carbon dioxide (CO2) emissions, which is directly
harming our planet. Therefore, by using SHC the carbon dioxide
emissions are reduced significantly.

9. 1.9
References:
 As per research and study

10. Last slide