scholarly journals A Comparative Study On Self-Healing Methods of Concretes By Sporosarcina Pasteurii Bacteria

2021 ◽  
Author(s):  
Mohammad Mirshahmohammad ◽  
Hamid Rahmani ◽  
Mahdi Maleki-Kakelar ◽  
Abbas Bahari
Keyword(s):  
Culture Medium ◽  
Healing Process ◽  
Calcium Nitrate ◽  
Healing Time ◽  
Concrete Mixture ◽  
Bacterial Cells ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Sporosarcina Pasteurii ◽  
Biological Methods

Abstract Biological methods (adding bacteria to the concrete mixtures) among the most recently investigated procedures increase the durability of concrete and repair concrete cracks. In the present study, different biological methods were used to heal the cracks of concrete and the most suitable method was subsequently introduced. For this purpose, the culture medium and bacterial nutrient inside the concrete mixes and curing solution were separately studied. The effect of air-entrained agent and various sources of calcium salts as the bacterial nutrient on the healing process was also studied. The results showed that the use of bacterial nutrient inside the concrete mixes has an affirmative impact on the mechanical properties and self-healing characteristics of concretes. With the simultaneous use of Sporosarcina pasteurii bacteria and calcium nitrate-urea or calcium chloride-urea as a bacterial nutrient in the concrete mixture, the 28 days compressive strength of concrete increases by 23.4% and 7.5%, respectively, which is due to calcium carbonate precipitation. The use of bacterial cells, nutrients, and culture in the concrete mixture provided the ability to heal wide cracks where the healing time is significantly reduced. On the other hand, separation of the bacterial culture medium slightly reduced the self-healing performance of concrete.

scholarly journals Immobilization of Bacterial Cells on Natural Minerals for Self-Healing Cement-Based Materials

2021 ◽  
Vol 7 ◽  
Author(s):  
Ilgin Sandalci ◽  
Mustafa Mert Tezer ◽  
Zeynep Basaran Bundur
Keyword(s):  
Water Absorption ◽  
Cement Paste ◽  
Healing Process ◽  
Pulse Velocity ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Bacterial Cells ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Main Challenge

Recent research in the field of concrete materials showed that it might be possible to develop a smart cement-based material that is capable of remediating cracks by Microbial-induced calcium carbonate precipitation (MICP). The early remediation of microcracks enables the design of cement-based systems with an elongated service life with a sustainable approach. However, the main challenge of the application is to extend the viability of the cells against the restrictive environment of cement-paste. These cells have to tolerate the highly alkaline conditions of cement paste, survive the mixing process, and remain viable even when access to nutrients is limited. This paper summarizes a novel study undertaken to investigate the self-healing efficiency of Sporosarcina pasteurii (S. pasteurii) cells immobilized on zeolite and sepiolite minerals having the same particle size. This manuscript reports an extensive experimental study to understand the factors influencing the efficiency of immobilization barriers, such as composition and reactivity. To obtain the bio-additive, the bacterial cells were immobilized without nutrients and additional nutrients were only provided during the curing stage after crack initiation. Screening of the healing process was done with ultrasonic pulse velocity (UPV) testing and stereomicroscopy. Further evaluation on performance was done by evaluating the decrease in water absorption capacity. The healing precipitate was characterized through Environmental Scanning Electron Microscope (ESEM) and Fourier-Transform infrared spectroscopy (FTIR). With this approach, the cracks on mortar surface were sealed and the water absorption capacity of the so-called self-healed mortar decreased compared to its counterpart cracked mortar samples. Sepiolite was found to be a more suitable bedding for the microorganisms compared to zeolite, therefore samples containing sepiolite exhibited a higher performance in terms of crack healing. The results showed that while vegetative cell immobilization on locally available materials is a simple and economically feasible approach the healing capacity of bacterial cells can be hindered due to the reactivity of the mineral.

ATP Simulation Hybrid Electrode Capacitor Self-Healing Circuit

2013 ◽  
Vol 397-400 ◽  
pp. 1893-1896
Author(s):  
Zhong Hua Kong ◽  
Li Gang Wu ◽  
Zai Fei Luo
Keyword(s):  
Equivalent Circuit ◽  
Healing Process ◽  
Healing Time ◽  
Self Healing ◽  
Plasma Resistance ◽  
Waveform Amplitude

In the paper hybrid electrode capacitor self-healing circuit is simulated through ATP. It illustrates the equivalent circuit of self-healing is correct, so self-healing process can be analysised quantitatively. The results are that the smaller is the plasma resistance, the larger is self-healing waveform amplitude, The larger is the experimental capacitor, the longer is self-healing time.

Soluble Silicates as Additives for Self-Sealing and Self-Healing Concrete

2016 ◽  
Vol 1813 ◽  
Author(s):  
L. E. Rendon Diaz Miron ◽  
M. E. Lara Magaña
Keyword(s):  
Mechanical Properties ◽  
Crack Formation ◽  
Healing Process ◽  
Self Healing ◽  
Reaction Products ◽  
Calcium Carbonate Precipitation ◽  
Broad Perspective ◽  
Healing Efficiency ◽  
Tensile Forces ◽  
Solubility Ratio

ABSTRACTTensile strength of concrete is limited and therefore is sensitive to crack formation. Steel reinforcement is added to bear the tensile forces; nonetheless, this does not completely omit crack formation. Repair of cracks in concrete is time-consuming and expensive. Self-sealing and self-healing of cracks upon appearance would therefore be a convenient property. We propose a mechanism to obtain self-repair of the concrete by adding soluble silicates (ASS) which will induce a self-sealing and self-healing process catalyzed by natural periods of wet and dry states of the concrete. Self-sealing approaches prevent the ingress of harsh chemical substances which may deteriorate the concrete matrix. This can be achieved by self-healing of concrete cracks (e.g. further cement hydration, calcium carbonate precipitation) and autonomous healing (e.g. further hydration of partially soluble silicates added as healing agents). The autogenous healing efficiency depends on the amount of deposited reaction products (ASS), its solubility (ratio of calcium to sodium silicate), the availability of water, and the crack width (restricted by adding microfibers). The self-sealing efficiency is generally evaluated by measuring the decrease in water permeability and air flow through the crack. The healing efficiency is usually evaluated by testing concrete´s regain in mechanical properties after crack formation; by reloading the cracked and autonomously healed specimen and comparing the obtained mechanical properties with the original ones. Self-sealing and self-healing of concrete gives a broad perspective and new possibilities to make future concrete structures more durable.

scholarly journals Ureolytic MICP-Based Self-Healing Mortar under Artificial Seawater Incubation

2021 ◽  
Vol 13 (9) ◽  
pp. 4834
Author(s):  
Xichen Sun ◽  
Jie Chen ◽  
Siyi Lu ◽  
Miaomiao Liu ◽  
Siyu Chen ◽  
...  
Keyword(s):  
Compositional Analysis ◽  
Fiber Surface ◽  
Healing Time ◽  
Artificial Seawater ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Sustainable Building ◽  
Sealing Capacity ◽  
Crack Sealing ◽  
Morphology Characterization

Ureolytic microbial-induced calcium carbonate precipitation (MICP) is a promising green technique for addressing sustainable building concerns by promoting self-healing mortar development. This paper deals with bacteria-based self-healing mortar under artificial seawater incubation for the sake of fast crack sealing with sufficient calcium resource supply. The ureolytic MICP mechanism was explored by morphology characterization and compositional analysis. With polyvinyl alcohol fiber reinforcement, self-healing mortar beams were produced and bent to generate 0.4 mm width cracks at the bottom. The crack-sealing capacity was evaluated at an age of 7 days, 14 days, and 28 days, suggesting a 1-week and 2-week healing time for 7-day- and 14-day-old samples. However, the 28-day-old ones failed to heal the cracks completely. The precipitation crystals filling the crack gap were identified as mainly vaterite with cell imprints. Moreover, fiber surface was found to be adhered by bacterial precipitates indicating fiber–matrix interfacial bond repair.

scholarly journals Detailed Analysis of the Influencing Parameters on the Self-Healing Behavior of Dynamic Urea-Crosslinked Poly(methacrylate)s

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3597 ◽  
Author(s):  
Abend ◽  
Zechel ◽  
Schubert ◽  
Hager
Keyword(s):  
Detailed Analysis ◽  
Mechanical Performance ◽  
Healing Process ◽  
Polymer Networks ◽  
Healing Time ◽  
The Self ◽  
Self Healing ◽  
Influencing Parameters ◽  
The Impact

For this paper, the self-healing ability of poly(methacrylate)s crosslinked via reversible urea bonds was studied in detail. In this context, the effects of healing time and temperature on the healing process were investigated. Furthermore, the impact of the size of the damage (i.e., area of the scratch) was monitored. Aging processes, counteracting the self-healing process, result in a decrease in the mechanical performance. This effect diminishes the healing ability. Consequently, the current study is a first approach towards a detailed analysis of self-healing polymers regarding the influencing parameters of the healing process, considering also possible aging processes for thermo-reversible polymer networks.

Silver nanowire loaded self-healing EVA films

2020 ◽  
pp. 089270572096216
Author(s):  
Ayse Sezer Hicyilmaz ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Healing Process ◽  
Composite Films ◽  
Ethylene Vinyl Acetate ◽  
Nucleating Agent ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Healing Time ◽  
Silver Nanowire ◽  
Nanocomposite Films ◽  
Self Healing

In this study, ethylene vinyl acetate (EVA) transparent nanocomposite films, which heal easily with the inclusion of a low amount of silver nanowire (AgNw), were produced. For this purpose, first AgNw was homogeneously dispersed in the polymer solution and then, nanocomposite films were produced from the solutions by casting method. The thermal, mechanical and optical properties of the produced films were characterized. Self-healing properties of nanocomposite films were confirmed by optical microscopy and mechanical tests. Optical microscope results showed that the optimum recovery temperature was 130°C and the addition of a small amount (5% w/w) of AgNw reduced the recovery time of the scratch on EVA film reducing the healing time by 66.66% (from 15 minutes to 5 minutes). In addition, tensile test results supported the optical microscope results. DSC results showed that the regular crystal regions were formed in composite films due to the high thermal conductivity and nucleating agent effect of AgNw. On the other hand, DSC curves proved that the healing process was occurred via re-entanglement of the polymer chains by heat effect, while silver nanowire addition did not affect the mechanical strength and transparency of the films, significantly. AgNw-loaded-EVA-based self-healing transparent films can be used for applications such as tempered glass laminates, electrical cables, coatings, packages, especially to protect the product and reduce the cost of repair.

scholarly journals Smart Self-Healing Capability of Asphalt Material Using Bionic Microvascular Containing Oily Rejuvenator

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6431
Author(s):  
Peng Yang ◽  
Li-Qing Wang ◽  
Xu Gao ◽  
Sai Wang ◽  
Jun-Feng Su
Keyword(s):  
Healing Process ◽  
Healing Time ◽  
The Self ◽  
Asphalt Pavements ◽  
Self Healing ◽  
Microstructure Observation ◽  
Micro Cracks ◽  
Healing Efficiency ◽  
Healing Temperature ◽  
The Individual

It has become one of the research directions of intelligent materials for self-healing asphalt pavements to use a bionic microvascular containing oily rejuvenator. The rejuvenator in a microvascular can carry out the healing of asphalt micro-cracks, thus reducing the damage to and prolonging the life of asphalt pavement. The aim of this work was to investigate the smart self-healing capability of an asphalt/microvascular material through its microstructure and mechanical properties. Microstructure observation indicated no interface separation between the microvasculars and bitumen matrix. Micro-CT images showed that microvasculars dispersed in asphalt samples without accumulation or tangles. The phenomenon of microcracks healing without intervention was observed, which proved that the fractured asphalt sample carried out the self-healing process with the help of rejuvenator diffusing out from the broken microvasculars. The self-healing efficiency of asphalt samples was also evaluated through a tensile test considering the factors of microvasculars content, healing time and healing temperature. It was found that the tensile strength of the asphalt samples was greatly enhanced by the addition of microvasculars under a set test condition. Self-healing efficiency was enhanced with more broken microvasculars in the rupture interface of the asphalt sample. During two self-healing cycles, the self-healing efficiency of the asphalt sample with three microvascular per 1 cm2 of a broken interface were able to reach 80% and 86%. This proves that microvasculars containing rejuvenator play a practical role in the self-healing process of asphalt. With an increase in temperature from 0 to 30 °C, the self-healing capability of the asphalt samples increased dramatically. An increase in time increased the self-healing capability of the bitumen samples. At last, a preliminary mathematical model also deduced that the self-healing efficiency was determined by the individual healing steps, including release, penetration and diffusion of the rejuvenator agent.

Reservation and Development of Rigid Pavement Quality with the Aid of Bacteria

2021 ◽  
Author(s):  
Saad Sarsam ◽  
◽  
Mohammed Sulaiman ◽  
Keyword(s):  
Service Life ◽  
Healing Process ◽  
Strength Properties ◽  
Water Bath ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Rigid Pavement ◽  
Flexure Strength ◽  
Healing Agent ◽  
Wheel Loading

Initiation of Microcracks in rigid pavement usually starts within few hours of casting due to the shrinkage of concrete and casting at hot environment condition. Cracking proceeds and changes to macrocracks throughout the service life of the pavement due to repetitions of compressive, tensile, and shear stress under wheel loading. Such cracking exhibits a durability problem since the ingress of moisture and harmful chemicals such as sulphates and chlorides into the concrete through the cracks can cause premature matrix degradation and corrosion of embedded steel reinforcement at joints, which may result in the decrement of strength and service life. In this work, implementation of self-healing techniques was adopted with the aid of bacteria and healing agent to precipitate CaCo3 on the formed micro-cracks. The precipitation of calcite by continuous hydration of cement helps in production of calcium carbonate precipitation with the help of bacteria. A soil bacterium named Bacillus subtilis was cultured in the laboratory, the concentration of bacteria cell of B. subtilits in normal saline (NaCl, 9 g/l) suspension was 106 cell/ml. Concrete specimens of various type (cube of 100x100x100 mm, cylinder of 100mm diameter and 200mm height, and beam of 100 x 100 x 500 mm) size have been prepared in the laboratory, then separated to three sets. The first set of specimens were subjected to controlled compression and flexure pre-cracking, then subjected to healing and curing in a water bath which contains the prementioned bacteria at 20°C for 7 days. The second set was the control specimens cured in water bath for 7 and 28 days at 20°C. The third set of specimens were subjected to healing and curing in a water bath which contains the prementioned bacteria at 20°C for 7 and 28 days and then tested for compressive, indirect tensile, and flexure properties. It was observed that the healing process provided by the bacteria have improved the overall properties of concrete by (23, 11 and 16) % for compressive, tensile and flexure strength respectively as compared to those of control mixture after 28 days of curing. On the other hand, specimens subjected to controlled pre-cracking exhibit improvement in strength properties after the healing process provided by the bacteria by (28 and 33) % for compressive and flexure strength respectively as compared to those of control mixture after 7 days of curing. It was concluded that spraying of bacterial water for curing the concrete is beneficial and can be considered as sustainable and environment friendly solution for maintenance. Bacteria can reserve, develop and maintain the quality of rigid pavement.

Determination of Micromechanical Properties of Cementitious Materials with Self-Healing Agent

2021 ◽  
Vol 880 ◽  
pp. 149-154
Author(s):  
Zdeněk Prošek ◽  
Pavla Ryparová ◽  
Aleš Jíra ◽  
Petr Bílý ◽  
Pavel Tesárek
Keyword(s):  
Culture Medium ◽  
Cementitious Materials ◽  
Carbonate Precipitation ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Spontaneous Crystallization ◽  
Agent Based ◽  
Micromechanical Properties ◽  
Healing Agent

The paper deals with the determination of nano, microstructural, and micromechanical properties of cementitious materials surface with self-healing agent based on calcium carbonate precipitation (calcite). This was done by means of electron microscopy with elemental microanalysis and nanoindentation. These methods can define parameters of individual phases within cementitious materials, which are important for the development of micromechanical models. Bacillus pseudofirmus in combination with culture medium 235 was chosen as a self-healing agent. Our study provides information about micromechanical properties of crystals resulting from spontaneous crystallization from the culture medium and from crystallization caused by bacteria.

scholarly journals Compatibility and Biomineralization Oriented Optimization of Nutrient Content in Nitrate-Reducing-Biogranules-Based Microbial Self-Healing Concrete

2021 ◽  
Vol 13 (16) ◽  
pp. 8990
Author(s):  
Beyza Kardogan ◽  
Kadir Sekercioglu ◽  
Yusuf Çagatay Erşan
Keyword(s):  
Microbial Activity ◽  
Dissolved Inorganic Carbon ◽  
Calcium Nitrate ◽  
Nutrient Content ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Precipitation Efficiency ◽  
Crack Repair ◽  
Calcium Formate

Microbially induced calcium carbonate precipitation (MICP) can be mentioned among the popular approaches to develop a self-healing concrete. The production of dissolved inorganic carbon through microbial activity is the main precursor for MICP in concrete and it is limited by the bioavailability of the nutrients. When nutrients are added to the mortar as admixtures, their bioavailability becomes more significant for crack repair because nutrients disperse in the mortar and considerable fraction stays far from a single crack. Therefore, the determination of bioavailability of nutrients and its variation with the initial nutrient content and crack age is essential to optimize a recipe for bacteria-based self-healing concrete. This study presents the optimum nutrient content defined for nitrate-reduction-based self-healing bioconcrete. In the tests, calcium nitrate (CN) and calcium formate (CF) were combined with a CF:CN w/w ratio of 2.50. Mortar properties and bioavailability of nutrients were analysed at different nutrient doses. Moreover, the bioavailability of nutrients at different crack ages changing between 3 and 56 days was monitored. Finally, resuscitation, microbial activity and the MICP performance of nitrate reducing biogranules were tested at defined nutrient bioavailabilties. The optimum nutrient content was determined as 7.00% (CF 5.00% and CN 2.00%). The leaching rates of formate ions were twice the leaching rate of the nitrate ions at similar initial concentrations, which led to a bioavailable HCOO−/NO3-N ratio of 23 g/g in cracked mortar. Under optimum nutrient conditions, the CaCO3 precipitation yield of nitrate reducing biogranules was recorded as 1.5 g CaCO3/g HCOO− which corresponded to 68% C precipitation efficiency.

Sign in / Sign up

Export Citation Format

Share Document