A SEMINAR SYNOPSIS
On
SELF-HEALING CONCRETE
Submitted by
K Sandeep (MT18CIV009)
Under the guidance of
Dr. Shashank Bhatra
(Trainee Teacher)
Department of Civil Engineering
National Institute of Technology, Uttarakhand
September-2019
CONTENT
1. Introduction
1.1. Definition
1.1.1. Types of Bacillus Bacteria
1.1.2. How the healing agents are applied
1.2. Applications of Self-Healing Concrete
1.3. Need
1.4. Practical Significance
2. Methodology
2.1. Literature review
3. Objectives of study
4. Expected Outcomes
5. References
1. Introduction:
Self-healing concrete is an artificial or synthetically created substance that has the built-in ability
to automatically repair the damage to itself without any external diagnosis or human intervention.
1.1. Definition
Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and
other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. To
tackle this we need bacterial concrete, which can successfully remediate cracks in concrete. The
mineral precipitation induced because of microbial activities is pollution free and natural.
1.1.1. Types of Bacillus Bacteria:
Bacillus alkalinitrulicus
Bacillus pasterurii
Bacillus sphaericus
Bacillus subtilis
Bacillus cohnii
Bacillus balodurans
Bacillus pseudofirmus
Escherichia coli
1.1.2. How the healing agents are applied
By direct application:
The bacteria and the chemical precursor are added directly while making the
concrete.
Encapsulation:
The part of the coarse aggregate is replaced by the lightweight aggregate, which is
impregnated with the twice the calcium lactate solution and the spores of bacteria.
1.2. Applications of Self-Healing Concrete
It can be used by oil and gas industries, which can stop small cracks frim becoming
spillways.
It can be used to strengthen any kind of Structural building, both existing and new.
It can be effective in the regions where buildings undergo freezing and thawing frequently.
It can proved to be economical in case of irrigation works, dams etc. which are directly in
contact with water.
1.3. Need
Concrete being widely used for construction purpose is susceptible to cracking leading to
loss in structural strength and performance thus requiring attention and maintenances
leading to huge economic and environmental dent thus by introducing self-healing concrete
with least human intervene is boon to the construction industry.
1.4. Practical significance
As the self-healing concrete can heal the cracks occurred by itself without any need of
supervision it gives us great advantage at places where humans cannot get i.e. at very
narrow places or where maintenances work could lead to traffic delay (tunnels) and many
more.
2. Methodology:
To do extensive literature review.
2.1. Literature review:
Jonkers and Schlangen (2007) reported that the mechanism of bacterially mediated calcite
production likely proceeds via organic carbon respiration with oxygen what results in
carbonate ion production under alkaline conditions. The produced carbonate ions, which can
locally reach high concentrations at bacterially active ‘hot spots’, precipitate with excess
calcium ions leaking out of the concrete matrix. One advantage of application of bacteria as
self-healing agent was that healing event not only revives bacterial cells but also potentially
results in the production of fresh spores what resets the viability status.
Schlangen et al (2010) studied the self-healing property of concrete by both bacteria and
ECC(engineered cementious composites).When bacteria was used lactate milk i.e. the food for
the bacteria need to be provided and if ECC had been used then with low water content fly ash
mixture was use to induce self-healing.
3. Objectives of study:
Research work of various authors will be read in order to understand the self-healing process
of cement concrete and study results obtained by them to come a conclusion for best process
for incorporating self-healing process and find out whether this material is put use in large
concrete structure works.
4. Expected outcome:
To find the best possible way to adopt the self-healing of cement concrete.
5. References:
Jonkers, H. M., & Schlangen, E. (2007, April). Crack repair by concrete-immobilized bacteria.
In Proceedings of the first international conference on self healing materials (pp. 18-20).
Schlangen, H. E. J. G., Jonkers, H. M., Qian, S., & Garcia, A. (2010). Recent advances on self
healing of concrete. In FraMCos-7: Proceedings of the 7th International Conference on
Fracture Mechanics of Concrete and Concrete Structures, Jeju Island, Korea, 23-28 May
2010.
