Determination of Bacterial Concrete Strength Using Bacillus Subtilis and Lightweight Expandable Clay Aggregate

Author(s):  
Dhiraj Ahiwale ◽  
Rushikesh Khartode

This study examines the impact of bacterial concrete on strength and self-healing. Bacterial concrete has better compressive strength, permeability, corrosion resistance, chemical precursors, alkalinity resistance, and mechanical stress. Bacillus subtilis calcium lactate and spore powder effects are explored in this study, and the influence of this bacterial form on strength and self-healing capacity to crack repair. The Bacillus subtilis concentration 105 cells/mL is used in concrete with calcium lactate 0.3% of cement. In another trial, calcium lactates 0.3% and spore powder 0.5% of cement with Bacillus subtilis concentration of 105 cells/mL and lightweight expandable clay aggregate (LECA) is 30% replaced to the coarse aggregate used in concrete respectively. The conventional concrete and bacterial concrete cubes were molded with dimensions of 150 mm x 150 mm x 150 mm, cylinders with dimensions of 100 mm x 200 mm, and a beam with dimensions of 100 mm x 100 mm x 500 mm. These specimens were evaluated after 7 and 28 days of cure. The compressive, split tensile, and flexural strength of bacterial concrete was raised by 23%, 8%, and 7%, respectively when compared to conventional concrete. Thus, the experimental findings reveal that Bacillus subtilis at 105 cells/ml cells with 0.3% calcium lactate has a substantial impact on the strength and self-healing of bacterial concrete.

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 17-22
Author(s):  
Martín Eduardo Espitia Nery ◽  
Dery Esmeralda Corredor Pulido ◽  
Paula Andrea Castaño Oliveros ◽  
Johan Andrey Rodriguez Medina ◽  
Querly Yubiana Ordoñez Bello ◽  
...  

Fissures in concrete structures result from structural deterioration and inadequate building processes, among other factors. Traditional in situ repair is often expensive and complex. For this reason, self-healing techniques have been developed, such as the use of bacteria that precipitate calcium carbonate and seal fissures. However, adding bacteria directly to the concrete matrix reduces bacterial survival. We present a review of different methods of bacterial encapsulation and their effects on fissure repair and concrete resistance. We argue that encapsulation of Bacillus subtilis in clay is the most promising method for this type of concrete, increasing concrete strength by 12% and repairing fissures of up to 0.52 mm.


This paper focuses on how the bacterium produces calcite to repair cracks and thereby increases the strength and durability of the concrete. The bacterial concrete can be made by embedding bacteria in the concrete to make it constantly precipitate calcite. Bacillus E Coli and Bacillus Subtilis JC3 are used for this purpose. Bacillus E coli and Bacillus Subtilis JC3 induced at cell concentration 10^5 cells/ml improves properties of concrete. This paper campaigns for the induction of bacteria in concrete for the promotion of self-healing cracks.


Author(s):  
Dr.Sarvesh, Et. al.

Concrete is usually a combination of cement, coarse particles (aggregates and Sand) and water. It is used to design and improve the infrastructures.It is used to design and improve the infrastructures. Concrete has many advantages and disadvantage. The main property that is characteristic to a concrete’s workability is its compressive strength. Only through this single test, one can judge if cementing has been done appropriately. Possible advancements for development include the use of non-traditional and creative materials, and the reuse of waste materials with a specific end goal to replenish the absence of specific assets and to discover alternative ways to monitor the Earth..This investigation concentrate on Compressive strength, flexural and split tensile strength of Conventional Concrete (CC) and Class C fly ash remains with bio-cement and natural pozzolans to consider the impact of bio-concrete with blend extents of 0%,0.25%,0.5%,1% and 1.5% on quality properties. Moreover, effective self-healing usually occurred due to the use of polymers, microorganism and additional cementing material. It is the key issue to find out the self-healing efficiency’s effect to sealing the crack width successfully. And good resistance was observed during the bacterial chemical process against the freeze and thaw attacks.


2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Ehizemhen C Igibah ◽  
Lucia Agashua ◽  
Abubakar Sadiq

With increasing population and demand for infrastructural development in many developing countries, the demand for concrete has been on the increase and does not show any sign of slowing down in the nearest future. Existing concrete structures are also deteriorating and require repair or replacement. In this study, multivariate methods of factor analysis (FA) and cluster analysis (CA), were applied to analyze the liquefied samples datasets for clean and contaminated (sewage) water obtained in Ado- Odo Ota, Ogun State, Nigeria. FA clearly identified two groups of liquefied samples and indicated that the bacterial parameters are higher in fermented locust beans water which can be likened to presence of bacillus subtilis food type. Hierarchical cluster grouped 40 samples into two which are high and low levels of bacteria contents respectively. Descriptive statistics showed all parameters significantly (conductivity, TDS, BOD, COD, carbondioxide, Calcium, Chlorine, pH, Temperature, salinity) in Cluster A greater than in cluster B. The main self- healing parameter for crack sealing up, because when bacteria commence feeding on calcium lactate once activated, oxygen consumed as the bacteria feeds and insoluble limestone formed by conversion of the soluble calcium lactate is greater for contaminated water against portable water values. This study demonstrates the usefulness of multivariate statistical techniques for evaluation of presence of bacteria in liquefied samples before used as self-healing. Keywords— Carbondioxide, clean, self-healing concrete, water.


Author(s):  
Ms. P.Kala Et. al.

Bacterial concrete is one of the methods of rectifying the micro-cracks developed in the structural elements made of concrete. The gram-positive type bacteria Bacillus subtilis when acquainted with concrete produces calcite precipitation which heals the micro cracks in the concrete. Bacillus subtilis was used with a cell concentration of 106. The optimised percentage replacement of fine aggregates with sugarcane fibres of grain size less than 4.75 mm was 0.1 %. The effect of sugarcane fibres on the durability of bacterial concrete is presented in this paper.To study the Stress -Strain behaviour of Sugarcane based Bacterial concrete (SBC), appropriate analytic SS model is developed that resembles the experimental behaviour of the various samples such as Conventional Concrete (CC), Bacterial Concrete (BC) and SBC. This work mainly targets on utilizing the earlier models and offers a new SS model that can well represent the actual SS behaviour of SBC samples. After finding the SS behaviour of CC, BC and SBC specimens experimentally, equations are developed to characterise axial SS behaviour of CC, BC and SBC samples. From these mathematical equations, theoretical stress for CC, BC and SBC are calculated and compared with test values. The proposed equations have exposed good connection with test values authorizing the mathematical model developed.


2022 ◽  
Vol 6 (1) ◽  
pp. 23
Author(s):  
Salmabanu Luhar ◽  
Ismail Luhar ◽  
Faiz Uddin Ahmed Shaikh

The development of cracks, owing to a relatively lower tensile strength of concrete, diverse loading, and environmental factors driving the deterioration of structures, is an inescapable key concern for engineers. Reparation and maintenance operations are thus extremely important to prevent cracks from spreading and mitigating the lifetime of structures. However, ease of access to the cracked zone may be challenging, and it also needs funds and manual power. Hence, autonomous sealing of cracks employing microorganisms into the concrete sans manual intervention is a promising solution to the dilemma of the sustainable improvement of concrete. ‘Ureolytic bacteria’, key organism species in rumen-producing ‘urease’ enzymes such as Bacillus pasteurii or subtilis—when induced—are capable of producing calcium carbonate precipitations into the concrete. As their cell wall is anionic, CaCO3 accumulation on their surface is extensive, and the whole cell, therefore, becomes crystalline and ultimately plugs pores and cracks. This natural induction technique is an environmentally friendly method that researchers are studying intensively. This manuscript reviews the application process of bacterial healing to manufacture autonomous self-healing bacterial concrete. Additionally, it provides a brief review of diverse attributes of this novel concrete which demonstrate the variations with the auto-addition of different bacteria, along with an evaluation of crack healing as a result of the addition of these bacteria directly into concrete or after encapsulation in a protective shell. Comparative assessment techniques for autonomous, bio-based self-healing are also discussed, accompanied by progress, potential, modes of application of this technique, and its resultant benefits in the context of strength and durability. Imperatives for quantitative sustainability assessment and industrial adoption are identified, along with the sealing of artificially cracked cement mortar with sand as a filling material in given spaces, as well as urea and CaCl2 medium treatment with Bacillus pasteurii and Sporosarcina bacteria. The assessment of the impact on the compressive strength and rigidity of cement mortar cubes after the addition of bacteria into the mix is also considered. Scanning electron microscope (SEM) images on the function of bacteria in mineral precipitation that is microbiologically induced are also reviewed. Lastly, future research scope and present gaps are recognised and discussed.


Author(s):  
Sohail Muhammad ◽  
Humair Ahmed Siddiqui

Crack growth is a major cause of failure in structures that are made using cement and concrete. Healing of these cracks can increase the life span of structures. In the present study micro-organism based self-healing of structures is studied. A commonly occurring micro-organism bacterium called Bacillus Subtilis, is used in the manufacturing of cement mortar blocks as a self-healing agent for cement mortar blocks, with the use of Calcium Lactate as feed for bacteria. In the first step, colonies of Bacillus Subtilis were grown and added with calcium lactate to produce a solution. The solution was then kept for one week to observe the metabolic product of Bacillus Subtilis. It was found that the bacterial product was composed of CaCO3 and thus the bacteria is suitable to be used as self-healing agent. Self-healing cement mortar blocks were made by adding Bacteria and Calcium Lactate with usual ingredients of cement mortar, i.e. cement, sand and water. It was found that the bacteria were also effective in converting Calcium Lactate to Calcium Carbonate, when mixed in cement mortar blocks. It was observed that the pores of cement mortar blocks were filled by Calcium Carbonate and that cracks get healed by the deposition of Calcium Carbonate in the cracks. Cement mortar blocks, with and without healing agent, were made to compare the effect of curing time. The samples were tested after seven, fourteen and twenty-eight days to compare the effect of healing agent. All the samples with the healing agent showed a higher compressive strength in comparison with the samples that were made without healing agent. Different percentages of Calcium Lactate, ranging from 1-7% were also used to find the best composition for future use. It was found that the compressive strength was increasing up to 5% while above 5% the increase was marginal thus it is proposed that Calcium Lactate should be used in between 5-7 % to reduce the cost of self-healing cement in construction industry.


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Katie Molyneux

Bacterial concrete is concrete in which bacteria are embedded and is a material which exploits the metabolic functions of these specially selected bacteria, genus Bacillus. The bacteria are amalgamated within clay pellets along with the nutrient calcium lactate. When the concrete around the pellet cracks, the pellets break, and the bacteria metabolise the calcium lactate to produce insoluble calcium carbonate, filling cracks up to ~2 mm wide. The addition of the clay pellets and the bacteria to the concrete improves its compressive and tensile strengths, making it better suited for applications where the concrete must endure severe stress. Consequently, the modulus of toughness is improved, though the extent of the improvement depends on the grade of concrete used. Bacterial concrete is industrially advantageous as its low coefficient of permeability and high acid durability factor makes it less prone to corrosion and less likely to require extensive repairs. This is ideal for structures that are difficult or expensive to maintain as well as for use in motorways that endure corrosion from salt used in de-icing. This review will focus on the properties of bacterial concrete and its industrial use. It reveals that despite higher initial costs, the enhanced properties of bacterial concrete compared to conventional concrete, makes it a more sustainable material in the long run with an overall benefit to global carbon emissions.


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