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International Journal of Civil Engineering and Technology (IJCIET) Volume 7, Issue 5, September-October 2016, pp. 275–283, Article ID: IJCIET_07_05_030
Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=5
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
APPLICABILITY OF CONCRETE TREATED WITH
SELF-HEALING BACTERIAL AGENTS
Ashish Babarao Gawande
Final Year Engineering Student, Department of Civil Engineering,
K.I.T’s College of Engineering, Kolhapur. India.
Yash Suneel Khandekar
Final Year Engineering Student, Department of Civil Engineering,
K.I.T’s College of Engineering, Kolhapur. India.
Ojas Pravin Rahate
Third Year Engineering Student, Department of Mechanical Engineering,
K.I.T’s College of Engineering, Kolhapur. India.
ABSTRACT
In this fast developing world, the face of the earth has transformed from a jungle to a concrete
jungle. These concrete structures provide the concrete foundation for the development of a country.
Large skyscrapers have emerged as the glory of the town. However, concrete has its limits with
respect to durability and long term sustainability. Crack formation micro as well as macro is a
major issue, these cracks eventually lead to formation of fractures and fissures, resulting in
collapse and accident. Concrete treated with healing bacteria, Bacilla pseudofirmus, Sarconima
pasteurii, proves an exceptional solution both for preplanning new projects and renovation of
existing structures as a part of post planning. Healing of cracks occurs in 3-4 weeks just after
formation of cracks, when the bacteria are exposed to moisture. The bacterium fills the cracks
effectively by formation of limestone. Thus, subsequent to healing, the structural strength is
retained. This method of self healing concrete also provides an ingenious method for production of
concrete bricks/blocks. Due to its better durability, it proves to be a better alternative than the
conventional counterparts. Moreover, existing method of brick production utilizing the kilns are
contributing towards rise in pollution levels, should bricks prepared from self healing concrete be
used, pollution levels can be virtually zero.
Key words: concrete jungle, long term sustainability, healing of cracks, limestone, virtually zero.
Cite this Article: Ashish Babarao Gawande, Yash Suneel Khandekar and Ojas Pravin Rahate,
Applicability of Concrete Treated with Self-Healing Bacterial Agents. International Journal of Civil
Engineering and Technology, 7(5), 2016, pp.275–283.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=5
1. INTRODUCTION
Kolhapur is a tourist city at the foothills of the Western Ghats which has a deep-rooted and ancient history.
A number of ancient structures such as forts and pilgrim places are responsible for scenic aesthetics of the
city, which are the main reasons for tourist footfall into the city.
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Ancient nature of these structures is the very reason that imparts the aesthetic beauty in them. Yet,
being old, parts of these structures are in dilapidated condition. Concrete avenues that mark the entry and
transit in the city are in a state of despair, leading to fall in tourist count, also, causing problems for the
residents. The famous panhala fort built by Chatrapathi SHIVAJI MAHARAJ in the seventeenth century
still stands gracefully but the sands of time has led to the deteriorating conditions of some parts of the forts.
Kolhapur being the major cultivator of sugarcane requires large amount of water for irrigation of acres
of farmlands. Irrigation canals present the most favorable medium for irrigation however it lacks in
durability due to formation of cracks.
Present day production of bricks in numerous kilns and furnaces poses a major environmental setback.
Large amounts of pollutants and the poisonous fumes like carbon monoxide, carbon dioxide, oxides of
sulfur and nitrogen and particulate matter are released into the atmosphere contributing to the pollution and
greenhouse effects. Furthermore this method of production is not efficient as a number of bricks get over
burned or broken hence rendered useless. At local level some of these pollutants are injurious to human
health and plant life. At global level this pollutants contribute to phenomenon of global warming and
global warming.
An innovative method of growing brick using bacteria and naturally abundant materials proves to be
better alternatives to conventional methods. Self healing concrete is the solution to all.
2. PROBLEMS
• Weak structural nature of old concrete buildings leads to cracks micro as well as macro.
• Due to extensive traffic on concrete roads, live load gets generated leading to wear and tear of the roads.
Water percolates through the cracks reaching the sub surface layer thus disturbing the structural integrity.
This affects the durability of roads and can have hazardous impacts on the traffic.
• Due to their ancient nature of construction, fort has excellent durability yet due to the seasonal variation and
weathering of rocks, their condition is started to deteriorate.
• Temperature variation leads to disturbance in the homogenous nature in the concrete structures leading to
gradual formation of cracks.
• Conventional methods of production of bricks lead to environmental pollution and also wastage of the
bricks.
Figure 1 Micro cracks Figure 2 Macro cracks
3. SELF HEALING CONCRETE MIXTURE
The cracks of 0.2mm can be healed but the cracks more than 0.2mm needs some healing agents o heal.
Because of the everyday chemical as well as physical reactions occurring on road, concrete has matured
self healing process. To enhance it, there is a need of addition of some healing agent for the concrete to
Ashish Babarao Gawande, Yash Suneel Khandekar and Ojas Pravin Rahate
http://www.iaeme.com/IJCIET/index.asp 277 [email protected]
heal properly within a given duration. Selection of concrete suitable bacteria is the most important task.
Also the study of bacteria is must. The bacteria should withstand high alkaline conditions and should
remain active over large span of time along with being chemically inert. Concrete constructions are
designed to last for many years so the bacteria used should also be feasible for a long time.
3.1. Mechanism of Healing
The capsules of bacteria and calcium lactate are inserted with the concrete during construction, the reason
to use it in the capsule form is to avert interaction between them. The capsules used are dormant and can
last upto a century. The concrete structures are bound to have microcracks due to the physical reactions
which decrease its durability. The capsules require water for their nutrition which gets leaked into the
cracks when they are exposed to environment. After reaction with water, calcium lactate forms limestone
which heals the cracks. It spreads throughout the cracks leading to the healing of the cracks .after
formation of limestone, the chances of water leaking inside is next to impossible. It leads to increase in the
sustainability. They are basically added as spores which are inactive having very high survival rate and
when the surviving conditions are against the odd, they active bacteria again forms spores and become
dormant.
3 days 7 days
14 days 28 days
40 days 200 days
Figure 3 Progress of crack healing.
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3.2. Self Healing Concrete in Dry Region
Since healing agent requires water for reaction, it is difficult to imply it in a dry region where there is
deficit of water. To encourage the use of self healing concrete in such dry regions, the use of plant fibres
along with self healing agent is suggested. The principle feature of plant fibres is that they have large
storage volume for liquids. They act as a reservoir for the healing agents for the supply of water so that it
can form limestone and the cracks can be healed. It primarily acts as glue. The diameter of plant fibres
should be 200 microns and ideal length should be 10mm.
Figure 4 Fibres in healing agent mix.
4. CASE STUDIES
The various statistics and study regarding the self healing concrete can be understood by the following case
studies.
4.1. Case Study 1
This case study portrays the advantages of cement treated with self healing agents in the form of
comparison between amount incurred in construction of cement road with conventional cement mix vs. the
cement treated with self healing agents.
For the purpose, a cement road of 2km from Kolhapur toll to Shivaji University. This cement road is a
two lane road prepared using conventional methods.
• Length of road = 2 km
• Breadth (2 lanes)= 24 m
• Depth = 0.38 m
• Volume = 18,240 m3
Ashish Babarao Gawande, Yash Suneel Khandekar and Ojas Pravin Rahate
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Figure 5 Route map of the stretch of the road considered.
4.1.1. Construction using Conventional Method
• Amount of Cement = 10.7 bags/m3
• COST of cement required = Rs.5,14,99,280
• Amount of Fine aggregate = 683.24 kg/m3
• COST of fine aggregate required = RS.96,32,945
• Amount of Coarse aggregate = 1108 kg/m3
• COST of coarse aggregate required = Rs.2,45,47,710
• Amount of Plasticisers = 4.6681l/m3
• COST of plasticisers required = Rs.1572
• Total cost of construction = Rs.8,56,81,507
4.1.2. Construction using Cement Treated with Self Healing Agents.
• Amount of cement = 9.23 bags/m3
• COST of cement required =Rs.4,59,64,800
• Amount of Fine aggregate= 673.3 kg/m3
• COST of fine aggregate required = Rs.94,92,816
• Amount of Coarse aggregate = 1006 kg/m3
• COST of Coarse aggregate required = Rs.2,22,88,409
• Amount of Plasticisers = 4.32l/m3
• COST of Plasticisers = Rs.1568
• Amount of SELF HEALING AGENT = 158.15 Kg/m3
• Cost of SELF HEALING AGENT required = Rs.2,61,51,869
• Total cost of construction = Rs.10,38,99,463.
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From the above statistics it is clear that construction cost of cement road using treated concrete is more
than that by using conventional methods. Although, the cost of construction has increased by about 2
crores, but on the long run, this method is actually economic. This can be understood by analyzing the
additional cost required for the repair and maintenance of roads made using conventional methods.
Furthermore, the bacteria lasts for a century, hence improving durability manifold. This is explained
elaborately in the Case Study 2.
4.2. Case Study 2
This case study basically indicates one of the many important applications of self healing agents. They
play a major role in increasing the service life of various structures such as buildings, canals, roads etc.
Self healing agents help combat the damages occurring due to ageing by crack filling.
For this case study, a bridge of cement road of span 0.5km located at the Tawade Hotel roundabout,
NH4 (Pune-Bengaluru Highway), Kolhapur is considered for the calculation of its maintenance cost. This
includes crack sealing, application of penetrating sealer, overlays and electrochemical treatment as a part
of routine maintenance on the damages induced due regular service and ageing.
Figure 6 Route map of bridge considered for case study 2.
Cost of maintenance is calculated as follows:
• Crack sealing – Rs.99.645 / sq.ft.
• Penetrating sealer – Rs.332.15 / sq.ft.
• Overlays – Rs.146.146 / sq.ft.
• Electrochemical treatment – Rs.3985.15 / sq.ft.
Note: the above shown values are approximate.
• Length of the bridge = 0.5 km = 3116 ft.
• Breadth of the bridge = 40 m = 131.2 ft.
• Total area = 4.08,819.2 sq.ft.
• Considering that 20% area of the bridge requires repairing, i.e, 8176.38 sq.ft.
• Cost of crack sealing = Rs.8,14,735.38
• Cost of penetrating sealer = Rs.27,15,784.617
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• Cost of Overlays = Rs.11,94,945.231
• Cost of electrochemical treatment = Rs.3,25,89,415.4
• Total cost of maintenance = Rs.3,73,14,880.63
With the implementation o f self healing agents, the above incurred maintenance cost can be reduced
manifold.
With self healing agents, the following data was obtained
• Area under consideration for repair = 8176.38 sq.ft.
• Cost of crack sealing (Rs.9.65/sq.ft.)= Rs.78,902.07
• Cost of penetrating sealer (Rs.132.15/sq.ft.)= Rs.10,80,508.617
• Cost of overlays (Rs.46.146/sq.ft.)= Rs.3,77,307.23
• Cost of electrochemical treatment (Rs.0/sq.ft.)= Rs.0.00
• Total cost of maintenance incurred= Rs.15,44,894.28
Due to crack healing properties of self healing agents, the above shown calculations justify its
importance of applicability. It is very clear that a colossal amount of about Rs.3,57,69,986.35 can be saved
on maintenance. Furthermore, by adding of self healing agents, the service life of various structures can be
improved exponentially and hence incur savings in the cost of maintenance.
4.3. Case Study 3
Bricks are the major part of any construction. So bricks should be durable and should last longer without
any damage. We visited a brick kiln in Kolhapur to collect information related to this case study. This case
study focuses on comparison between conventional bricks, concrete bricks and self healing concrete
bricks.
Figure 7 Brick kiln for preparation of conventional bricks
4.3.1. Conventional Bricks
• Dimensions-19*19*9
• Cost of bricks-5-7 Rs.
• Fuel used-coal and biomass
• Gases emitted
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GASES COAL BIOMASS
SO2 (mg/Nm cube) 5.2-943.2 18.3-52.4
CO (mg/Nm cube) 355-3579 2622-5026
CO2 % 1.0-2.4 1.7-2.0
In a brick kiln in Kolhapur, approximately one lakh bricks are prepared out of which 20% are damaged
and are of no use. In addition to this, fuel is required for burning which causes pollution. Some experts say
that pollution from brick kilns is worse than that of factories.
Burning of coal in brick kilns leads to formation of smoke which emits gaseous pollutants like sulfur
dioxide, nitrogen oxide and particulate matter. A substance known as poly aromatic hydrocarbon is also
emitted which causes vomiting, diarrhea, nausea and eye irritation and even cancer.
4.3.2. Concrete Bricks
• Dimensions- 6*8*12 in.
• Cost of brick-13 Rs
4.3.3. Self Healing Agent Bricks
Bricks made with self healing agents and concrete do not cause any type of pollution or harm to the
environment. There is no fuel required for their production that’s why there is no pollution occurring. Also
self healing agent bricks last longer as compared to conventional bricks due to the ability of self healing
agents to repair the bricks.
5. CONCLUSION
• Self healing concrete is a new technology developed in Delft University, Netherlands. This concrete has
bacteria in the form of capsules which remain dormant till 100 years unless it receives water which is its
nutrient to become active and multiplicate. Capsules receive water only when exposed to the environment
which is possible when cracks appear in the structures.
• The bacteria heal the cracks or gap within three to four weeks by producing limestone as its byproduct.
• The cost of construction for constructing cement road has increased by about 2 crores with the
implementation of self healing agents in the cement. However, on the long run, this method is actually
economic. This can be understood by analyzing the additional cost required for the repair and maintenance
of roads made using conventional methods.
• From our case study of analysis of maintenance cost required for a bridge, we conclude that by adding of
self healing agents, the service life of various structures can be improved exponentially and hence incur
savings in the cost of maintenance.
• Method of preparation of conventional bricks involve the process of baking the bricks in large kilns. This
process is not environmental friendly as it involves release of poisonous gases into atmosphere, contributing
towards green house effect.
• We can prepare bricks using self healing concrete which are environmental friendly as they are not produced
in kilns and are more durable than conventional bricks.
Ashish Babarao Gawande, Yash Suneel Khandekar and Ojas Pravin Rahate
http://www.iaeme.com/IJCIET/index.asp 283 [email protected]
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