scholarly journals A Study on Biomineralization using Bacillus Subtilis Natto for Repeatability of Self-Healing Concrete and Strength Improvement

2019 ◽  
Vol 17 (12) ◽  
pp. 700-714
Author(s):  
Nguyen Ngoc Tri Huynh ◽  
Kei-ichi Imamoto ◽  
Chizuru Kiyohara
Keyword(s):  
Bacillus Subtilis ◽  
Self Healing ◽  
Strength Improvement

Bio-inspired self-healing and self-sensing cementitious mortar using Bacillus subtilis immobilized on graphitic platelets

2022 ◽  
Vol 316 ◽  
pp. 125818
Author(s):  
Rao Arsalan Khushnood ◽  
Ajlal Arif ◽  
Nafeesa Shaheen ◽  
Ahmad Gul Zafar ◽  
Talal Hassan ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Self Healing

scholarly journals Bioprecipitation of calcium carbonate by Bacillus subtilis and its potential to self-healing in cement-based materials

2020 ◽  
Vol 18 (5) ◽  
Author(s):  
Héctor Ferral Pérez ◽  
Mónica Galicia García
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Building Materials ◽  
Soil Stabilization ◽  
Amorphous Material ◽  
Crystallinity Index ◽  
Self Healing ◽  
Semi Solid ◽  
A Minor ◽  
Novel Applications

In recent years, biological mineralization has been implemented as a viable option for the elaboration of new building materials, protection and repair of concrete by self-healing, soil stabilization, carbon dioxide capture, and drug delivery. Biogenic mineralization of calcium carbonate (CaCO3) induced by bacterial metabolism has been proposed as an effective method. The objective of the present study was to characterize the bioprecipitation of CaCO3 crystals by Bacillus subtilis in a semi-solid system. The results show that CaCO3 crystals were produced by day 3 of incubation. The prevalent crystalline polymorph was calcite, and in a minor proportion, vaterite. The presence of amorphous material was also detected (amorphous CaCO3 (ACC)). Finally, the crystallinity index was 81.1%. This biogenic calcium carbonate does not decrease pH and does not yield chloride formation. Contrary, it increases pH values up to 10, which constitutes and advantage for implementations at reinforced concrete. Novel applications for biogenic calcium carbonate derived from Bacillus subtilis addressing self-healing, biocementation processes, and biorestoration of monuments are presented.  

scholarly journals Mechanisms of encapsulation of bacteria in self-healing concrete: review

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 ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Concrete Strength ◽  
Self Healing ◽  
Bacterial Survival ◽  
Precipitate Calcium Carbonate ◽  
Structural Deterioration ◽  
Bacterial Encapsulation ◽  
Concrete Matrix ◽  
In Situ Repair

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.

scholarly journals Compressive strength of bacterial concrete by varying concentrations of E.Coli and JC3 bacteria for Self-Healing Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 3659-3661
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Cell Concentration ◽  
Self Healing ◽  
E Coli ◽  
Strength And Durability ◽  
Bacterial Concrete

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.

scholarly journals Self-healing bacterial cementitious concrete composites: development and performance evaluation

2021 ◽  
Author(s):  
Sini Bhaskar
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Statistical Modelling ◽  
Energy Dispersive Spectrum ◽  
Ultrasonic Pulse Velocity ◽  
Pulse Velocity ◽  
Self Healing ◽  
Chloride Permeability ◽  
Sporosarcina Pasteurii ◽  
Subtilis Subsp

The principal objective of the research is to contribute towards attaining the goal of developing self-healing cementitious concrete composites by incorporating bacteria as healing agent. Since the root cause of the majority of structural failure is attributed to concrete cracking, there is a compelling economic incentive to develop a concrete that can treat and repair the damage all by itself. Even though some research has been carried out in this area, a major breakthrough in identifying the types of bacteria, modes to protect this bacteria from high pH concrete environment and nutrients for effective healing are yet to materialise. For the present study, three different bacteria namely, Sporosarcina ureae, Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii and two protective vehicles such as zeolite and pumice were selected to determine the best combination among them for self-healing. Normal and fibre reinforced mortar and engineered cementitious composite (ECC) specimens were employed for the study. In order to develop self-healing bacterial concrete based materials, it is crucial to understand whether the introduction of mineral producing bacteria and nutrients adversely affect the properties. Thus, various concentrations of bacteria and nutrients were tested to determine the best possible combinations without sacrificing concrete properies. Evaluation of healing effect was determined by comparing compressive strength, sorptivity and rapid chloride permeability (RCPT), four point bending and ultrasonic pulse velocity (UPV) properties of sound and damaged specimens at different ages. Healing associated with crack closure was visualised and analysed using scanning electronmicroscopy (SEM), Energy Dispersive Spectrum Energy (EDS) and X-ray diffraction (XRD) studies. Finally, an attempt was made to employ statistical models for parameter optimization of self-healing characteristics in terms of compressive strength, sorptivity, RCPT and UPV by design and analysis of experiments. Evaluation of results to determine self-healing efficiency indicated that a significant amount of self-healing was achieved by all three selected bacteria, out of which Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii found to be promising choices. Both zeolite and pumice turned out to be effective protective vehicles. Statistical modelling of the experiment proved to be the ideal choice for modelling self-healing characteristics.

Self-Healing Microbial Concrete - A Review

2020 ◽  
Vol 990 ◽  
pp. 8-12
Author(s):  
Sasan Farhadi ◽  
Shervin Ziadloo
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Concrete Structure ◽  
Concrete Durability ◽  
Self Healing ◽  
Bacillus Pasteurii ◽  
Structure Degradation ◽  
Healing Agent

The cracks naturally exist in concrete and make it weak to the deleterious environment, ending with structure degradation. According to this fact, concrete requires to be improved and remediated. Self-healing methods are considered as a helpful way to mitigate the propagation and development of the cracks in the concrete. Bio-mineralization methods can heal the concrete by using bacteria suchlike Bacillus subtilis and Bacillus pasteurii, which can seal the cracks by CaCO3 precipitation. The literature represents the MICP method of using bacteria in concrete, which can improve the concrete durability by increasing the compressive strength. Furthermore, the different kinds of bacteria used in the concrete structure and the methods of employing as a self-healing agent review. Moreover, it illustrates B. Pasteurii and B. Sphaericus has more efficient results between other bacteria due to increasing the compressive strength and lifespan of the concrete.

Bio-inspired self-healing cementitious mortar using Bacillus subtilis immobilized on nano-/micro-additives

2018 ◽  
Vol 30 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Rao Arsalan Khushnood ◽  
Siraj ud din ◽  
Nafeesa Shaheen ◽  
Sajjad Ahmad ◽  
Filza Zarrar
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Iron Oxide ◽  
Cement Mortar ◽  
Healing Process ◽  
Main Concern ◽  
Scanning Electron Micrographs ◽  
Self Healing ◽  
Micro Cracks ◽  
Cracked Specimens

Bio-inspired self-healing strategies are much innovative and potentially viable for the production of healable cement mortar matrix. The present research explores the feasibility of gram-positive “Bacillus subtilis” microorganisms in the effective healing of nano-/micro-scale-induced structural and non-structural cracks. The main concern related to the survival of such microorganisms in cementitious environment has been successfully addressed by devising proficient immobilization scheme coherently. The investigated immobilizing media includes iron oxide nano-sized particles, micro-sized limestone particles, and milli-sized siliceous sand. The effect of induced B. subtilis microorganisms immobilized on nano-micro-additives was analyzed by the quantification of average compressive resistance of specimens (ASTM C109) and healing evaluation. The healing process was mechanically gauged by compressive strength regain of pre-cracked specimens after the healing period of 28 days. The pre-cracking load was affixed at 80% of ultimate compressive stress “[Formula: see text]” while the age of pre-cracking was kept variable as 3, 7, 14, and 28 days to precisely correlate healing effectiveness as the function of cracking period. The healing mechanism was further explored by examining the healed micro-crack using field emission scanning electron micrographs, energy dispersive x-ray spectrographs, and thermogravimetry. The results revealed that B. subtilis microorganisms contribute extremely well in the improvement of compressive strength and efficient healing process of pre-cracked cement mortar formulations. The iron oxide nano-sized particles were found to be the most effective immobilizer for preserving B. subtilis microbes till the generation of cracks followed by siliceous sand and limestone particles. The micro-graphical and chemical investigations endorsed the mechanical measurements by evidencing calcite precipitation in the induced nano-/micro-cracks as a result of microbial activity.

scholarly journals BAKTERI BACILLUS SUBTILLS SEBAGAI AGEN SELF HEALING CONCRETE DENGAN VARIASI PERSENTASE DAN NILAI PH

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Fauzan Gumelar ◽  
Rika Nuraini
Keyword(s):  
Bacillus Subtilis ◽  
Self Healing

Material yang selalu digunakan sebagai pengisi dari struktur adalah beton, dikarenakan memiliki kuat tekan yang kuat dan pembuatannya mudah. Sampai saat ini, telah banyak dilakukan berbagai inovasi terhadap beton dan salah satunya adalah dengan memanfaatkan bakteri agar beton dapat memiliki kemampuan untuk menutup kerusakan berupa retakan secara mandiri atau biasa disebut dengan self healing concrete. Tujuan pada penelitian kali ini adalah untuk mengetahui pengaruh dari beton dengan bahan tambah bakteri bacillus subtilis yang dienkapsulasi dengan persentase sebesar 0,5% dan 1%. Beton tersebut akan diuji kuat tekan dan dibandingkan dengan beton normal. Setelah itu, beton dengan bahan tambah kapsul bakteri akan direndam dalam air selama 14 hari dengan nilai pH yang berbeda- beda sebagai pengujian self healing concrete. Hasil penelitian menunjukkan bahwa nilai kuat tekan beton normal 25,18 Mpa, beton dengan bahan tambah enkapsulasi bakteri sebesar 0,5% memiliki nilai kuat tekan 24,51 Mpa, dan beton dengan bahan tambah enkapsulasi bakteri sebesar 1% memiliki nilai kuat  tekan 26,20 Mpa. Pengujian self  healing concrete menunjukkan bahwa beton dengan bahan tambah enkapsulasi bakteri sebesar 0,5% pada perendaman air dengan nilai pH 7 selama 14 hari, dinilai yang paling baik dalam menutupi retak pada beton.

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