Concrete Technology Project: Bacterial Concrete

Introduction:

The subject of concrete technology is not unknown to the field of construction industry as well as other industries. It is the most common subject for the selection of project work at the academics in the engineering institutes. Taking a look over the subject it is undergone a numbers of research in the industry as well as academics. It is important to identify the appropriate region of the subject to explore it for the research work. There are various types of concrete available to research for the specific purpose. Most of the times in academics research project on concrete technology are only specified for the identification or analysis of the properties after addition of admixtures or materials. In contrast industry work only based on the product development or optimizing the product as per the needs of market. In the current article we will discuss the Bacterial Concrete, its basic introduction and other details related to academic projects.

Basics of Bacterial Concrete:

As we already know that concrete structures have to bear numbers of loads and stresses due to several factors. These factors cause small or large cracks in the structure which leads towards the decrease in strength of the structure^[1]. To get repaired those cracks needs different solutions. Numbers of remedial measures are available in the market as per the need of structure repair and type of crack or damage. To select an appropriate method for the repair of such small cracks or damage due to internal or external stresses is essential in terms of desired effects and economic as well^[7]. As an example using epoxy materials for the repair will cost you higher amount and also it requires constant maintenance. As same use of chemical materials are not in the criteria of environment friendly process. That is the primary reason to introduce the method which is environment friendly, cost as normal concrete, provides desired strength for the specific application along with healing factor to reduce the repair and maintenance cost. Bacterial concrete is the splendid alternative for such applications^[2].

The bacterial concrete is also known from various other names as per its materials / elements. Self healing concrete, Biological concrete are the other names of it. The bacterial concrete is formed with the addition of specific types of bacteria into the mix. These bacterial provides healing factor to the concrete mix against cracking without any additional mechanism of repair due to which is also known as self healing concrete. A name biological concrete represents the use of biological living elements in the concrete mix.

The novel method of environment friendly crack healing using biological process in the concrete was first introduced in 1995 by Gollapudi (U.K. Gollapudi et al., 1995) quoted in the study of S.S. Bang and V. Ramakrishnan, 2001^{[5 - 7]}. The process of using biological elements in the concrete mix is also known as bio mineralization. The process of bio mineralization is basically a precipitation of calcium carbonate caused due to incorporating calcite bacteria. When it comes in contact with water it will precipitate calcium carbonate and the formula will heal the crack^{[2, 3]}.

Image: Bacterial Organism Process (Source: Hammes & Verstraete., 2002)^[20]

Above figure is representing the carbonate precipitation process in a concrete mix^[19][20].

• Image A – It is representing the release of DIC (Dissolved Inorganic Carbon) & AMM (Ammonium) due to addition of Urea in the bacterial mix. In the mixture calcium ions are attracted towards the cell wall of bacteria due to opposite charges.
• Image B – Calcium carbonate’s heterogeneous precipitation takes place on the cell wall of bacteria caused by supersaturation in the presence of calcium ions.
• Image C – The whole cell encapsulated after some time.
• Image D – involvement of bacterial cell in the process of carbonate precipitation.

Table: Application of different bacterial organism in various operations ^{[8 – 19]}

Application	Organism	Literature
Concrete & Cement mortar	Bacillus cereus Bacillus sp. CT-5 Bacillus pasteurii Shewanella Sporosarcina pasteurii	Le Metayer- Leverel et al (1999) Achal et al., 2011b Ramachandran et al (2001) Ghosh et al (2005) Achal et al (2011a)
Crack repair in concrete	Sporosarcina pasteurii Bacillus pasteurii Bacillus pasteurii Bacillus sphaericus Bacillus sphaericus	Bang et al (2001) Ramachandran et al (2001) Ramakrishnan (2007) De Belie et al (2008) De Muynck et al (2008a, b)
Self Healing	Bacillus pseudifirmus Bacillus cohnii	Jonkers et al (2007)

To understand better about the effects on the strength characteristics of concrete due to bacterial organism, a table of several researches is presented here. From this it will easy to understand the effects^[7].

Table: Comparison of results of previous research work

Type of Strength	Author	Bacteria	Mixed with	Increase in strength
Compressive Strength	Abhijitsinh Parmar et al. (2013)	Bacillus cohnii	Ennore Sand	20%
	Abhijitsinh Parmar et al. (2013)	Bacillus sphaericus	Ennore Sand	18.60%
	Harshad Patel et al. (2013)	Bacillus cohnii	Fly ash	23.58%
	Gandhimathi A., Suji D., and Elayarajah B. (2015)	Bacillus sphaericus	Ennore Sand	31.11%
	Koustubh A. Joshi, Madhav B. Kumthekar and Vishal P. Ghodak (2016)	Bacillus subtilis	Directly Mixed	26.66 to 52.71%
		Bacillus pasteurii (NCL 24.77)	Directly Mixed	26%
		Bacillus sphaericus (NCL 24.78)
Flexural Strength	Abhijitsinh Parmar et al. (2013)	Bacillus sphaericus	Ennore Sand	4.30%
	Abhijitsinh Parmar et al. (2013)	Bacillus cohnii	Ennore Sand	6.78%

Materials:

To complete the project you will need the basic ingredients of concrete i.e. cement, sand, aggregates, and water. In addition as we are practicing bacterial concrete we need to add specific type of bacterial organism in the concrete mix.

The bacteria used in concrete mix are classified in three different ways. As per shape there are Spirilla, Bacilli, Cocci. For gram stain there are gram positive and gram negative. As per oxygen demand there are Aerobic and Anaerobic bacteria^[3]. Some of the common types of bacteria used in previous studeis are as follow: Bacillus subtilis, Bacillus pseudofirmus, Bacillus pasteurii, Bacillus sphaericus, Escherichia coli, Bacillus cohnii, Bacillus balodurans, Bacillus halodurans, etc.^[4]

Method:

There are two methods for the application of bacterial concrete in the industry. The first method comprises application of bacteria in the concrete mix at the mixing stage. It will produce the concrete having modified properties of high durability and high strength characteristics. In the second method the bacteria are introduced in the hardened concrete for the purpose of repair of cracks and damage. The only limitation of second method is the depth of crack and its healing time. The method is not suitable for the concrete surface having crack of more than 25 mm in depth. As same the healing time may take up to one month for the complete repair of the damaged part which is not feasible in case of emergency repair works. It is notable to identify the proportion of the bacteria to be mixed in the mixture or application of bacterial mix in the crack, which can be obtained with help of mix design.

Methodology:

• Selection of topic for the project in terms of property analysis or concrete production 
• Selection of bacterial organism.
• Identifying the amount of concrete to be produced as per the numbers of test using volumetric calculations 
• Calculation of materials with the help of mix design procedure.
• Application of mix design and producing cubes, beams or slabs of concrete for the further testing
• Discussion of result and analysis
• Conclusion
  

Project Scope:

As we have discussed in the above topics there are numbers of research work is going on in the industry as well as academic institutes. The selections of topics of such projects in the academic institutes are depended on the available resources, availability of specialized faculty or guide in the institute. Considering concrete technology for bacterial concrete there are limited scope in terms of research. Still, it is possible to expansion of the project by addition of other materials to analyze the combine effects of bacterial organism and admixtures. Following are the main region of topics that can be used to prepare your own project title.

• Critical review on bacterial concrete
• Analysis of strength characteristics for bacterial concrete
• Analysis of concrete properties due to bacterial organism
• Analysis of bacterial organism of bacterial concrete with admixtures (mineral/chemical)
• Repair of concrete blocks using bacterial organism

References:

[1] Abhishek Thakur, Akshay Phogat and Khushpreet Singh, Bacterial Concrete and Effect of Different Bacteria on the Strength and Water Absorption Characteristics of Concrete: A Review. International Journal of Civil Engineering and Technology, 7(5), 2016, pp.43–56.

[2] V Srinivasa Reddy, M V SeshagiriRao, S Sushma. Feasibility Study on Bacterial Concrete as an innovative self crack healing system. International Journal of Modern Trends in Engineering and Research, e-ISSN No.:2349-9745, Volume 2, Issue 7, [July-2015] Special Issue of ICRTET’2015, Date: 2-4 July, 2015, PP 642-647.

[3] Palanisamy, Magudeaswaran. (2017). Bacterial concrete: A review. International Journal of Civil Engineering and Technology. 8. 588-594.

[4] El˙zbieta Stanaszek-Tomal, Bacterial Concrete as a Sustainable Building Material?, Sustainability 2020, 12, 696; doi:10.3390/su12020696.

[5] Gandhimathi, A., Vigneswari, N., Janani, S.M., Ramya, D., Suji, D. and Meenambal, T. 2012. “Experimental Study on Self–Healing Concrete”, Emerging Trends in Engineering Research.

[6] U.K. Gollapudi, C.L. Knutson, S.S. Bang, M.R. Islam, A new method for controlling leaching through permeable channels, Chemosphere, Volume 30, Issue 4, 1995, Pages 695-705, ISSN 0045-6535, https://doi.org/10.1016/0045-6535(94)00435-W.

[7] Chapter 07, Abhijitsinh Parmar, Kaushal Raval, Sachin Bhavsar and Dixitkumar Patel, “Special Concretes: Materials and Mix Designs”, Studium Press (India) Pvt. Ltd., ISBN 13 : 978-93-85046-54-4.

[8] Achal, V.; Mukherjee, A. & Reddy, M.S. (2011a). Effect of calcifying bacteria on permeationproperties of concrete structures, J Ind Microbiol Biotechnol, Vol. 38, pp. 1229-1234.

[9] Achal, V.; Mukherjee, A. & Reddy, M.S. (2011b). Microbial Concrete: A Way to Enhance the Durability of Building Structures, J Mater Civ Eng, Vol. 23, pp. 730-734. Bang, S.S.; Galinat, J.K. & Ramakrishnan, V. (2001). Calcite precipitation induced by polyurethane-immobilized Sporosarcina pasteurii, Enzyme Microb. Technol., Vol.28, pp.404–409.

[10] De Belie, N. & De Muynck,W. (2008). Crack repair in concrete using biodeposition. In: Proc. of ICCRR, Cape Town, South Africa.

[11] De Muynck,W.; Cox, K.; De Belie, N. & Verstraete,W. (2008a). Bacterial carbonate precipitation as an alternative surface treatment for concrete, Constr. Build. Mater., Vol. 22, pp. 875–885.

[12] De Muynck,W.; Debrouwer, D.; De Belie, N. & Verstraete,W. (2008b). Bacterial carbonate precipitation improves the durability of cementitious materials, Cem. Concr. Res., Vol. 38, pp.1005–1014.

[13] Ghosh, P.; Mandal, S.; Chattopadhyay, B.D. & Pal, S. (2005). Use of microorganism to improve the strength of cement mortar, Cem. Concr. Res., Vol. 35, pp.1980–1983.

 [14] Jonkers, H.M. & Schlangen, E. (2007). Crack repair by concrete-immobilized bacteria.In: Schmets, A.J.M., van der Zwaag, S. (Eds.), Proc. of First International Conference on Self Healing Materials, Noordwijk, The Netherlands.

[15] Le Metayer-Levrel, G.; Castanier, S.; Orial, G.; Loubiere, J.F. & Perthuisot, J.P. (1999). Applications of bacterial carbonatogenesis to the protection and regeneration of limestones in buildings and historic patrimony. Sedimentary Geology Vol. 126, pp. 25–34.

[16] Le Metayer-Levrel, G.; Castanier, S.; Orial, G.; Loubiere, J.F. & Perthuisot, J.P. (1999). Applications of bacterial carbonatogenesis to the protection and regeneration of limestones in buildings and historic patrimony, Sediment. Geol., Vol. 126, pp. 25–34.

[17] Ramachandran, S.K.; Ramakrishnan, V. & Bang, S.S. (2001). Remediation of concrete using micro-organisms, ACI Materials journal, Vol. 98, pp. 3–9.

[18] Ramakrishnan, V. (2007). Performance characteristics of bacterial concrete—a smart biomaterial. In: Proceedings of the First International Conference on Recent Advances in Concrete Technology, Washington, DC, 2007, pp. 67–78.

[19] Dhami, Navdeep & Reddy, Mondem & Mukherjee, Abhijit. (2012). Biofilm and Microbial Applications in Biomineralized Concrete. 10.5772/31124.

[20] Hammes, F. & Verstraete,W. (2002). Key roles of pH and calcium metabolism in microbial carbonate precipitation, Rev. Environ. Sci. Biotechnol. Vol. 1, pp. 3–7.