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.

scholarly journals Production of concrete compatible biogranules for self-healing concrete applications

2019 ◽  
Vol 289 ◽  
pp. 01002 ◽  
Author(s):  
Merve Sonmez ◽  
Yusuf Cagatay Ersan
Keyword(s):  
Calcium Nitrate ◽  
Nutrient Content ◽  
Early Age ◽  
Self Healing ◽  
Fresh Properties ◽  
Microbial Cultures ◽  
Production Strategy ◽  
Rebar Corrosion ◽  
Cost Efficient ◽  
Calcium Formate

Recently, cost-efficient nitrate reducing biogranules were suggested as an alternative to axenic microbial cultures for development of microbial self-healing concrete. In a marine environment, biogranule containing microbial self-healing concrete showed simultaneous self-healing of cracks and immunisation against rebar corrosion. Yet, information about the production strategy of these biogranules and their compatibility with a mortar matrix is limited. This study presents the production of biogranules and their compatibility with mortar specimens when incorporated at dosages between 0.36% to 4.30% w/w cement (0.25% to 3% of bacteria w/w cement). In-house produced biogranules composed of 70% bacteria and 30% of minerals w/w of biogranule were used for the compatibility tests. In test mortars, calcium formate (CF) and calcium nitrate (CN) were used as regular nutrient admixtures, and nutrient content was set identical in every batch. Up to 2.9% incorporation, biogranules had no significant influence on the fresh properties of mortar. More than 2.9% incorporation caused poor workability and a 26% decrease in 3-Day compressive strength of biomortar specimens. Overall, the biogranules produced are compatible with a cementitious matrix up to 2.9% w/w cement, and even up to 3.6% if early age strength is not essential, which makes biogranules one of the most compatible microbial healing agents among the suggested agents in the literature.

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 Self-Healing Concrete by Biological Substrate

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4099 ◽  
Author(s):  
How-Ji Chen ◽  
Ching-Fang Peng ◽  
Chao-Wei Tang ◽  
Yi-Tien Chen
Keyword(s):  
Calcium Carbonate ◽  
Lightweight Aggregate Concrete ◽  
White Crystal ◽  
Repair Material ◽  
Self Healing ◽  
Bacterial Strains ◽  
Calcium Carbonate Precipitation ◽  
Bacillus Pasteurii ◽  
Concrete Crack ◽  
Crack Repair

At present, the commonly used repair materials for concrete cracks mainly include epoxy systems and acrylic resins, which are all environmentally unfriendly materials, and the difference in drying shrinkage and thermal expansion often causes delamination or cracking between the original concrete matrix and the repair material. This study aimed to explore the feasibility of using microbial techniques to repair concrete cracks. The bacteria used were environmentally friendly Bacillus pasteurii. In particular, the use of lightweight aggregates as bacterial carriers in concrete can increase the chance of bacterial survival. Once the external environment meets the growth conditions of the bacteria, the vitality of the strain can be restored. Such a system can greatly improve the feasibility and success rate of bacterial mineralization in concrete. The test project included the microscopic testing of concrete crack repair, mainly to understand the crack repair effect of lightweight aggregate concrete with implanted bacterial strains, and an XRD test to confirm that the repair material was produced by the bacteria. The results show that the implanted bacterial strains can undergo Microbiologically Induced Calcium Carbonate Precipitation (MICP) and can effectively fill the cracks caused by external concrete forces by calcium carbonate deposition. According to the results on the crack profile and crack thickness, the calcium carbonate precipitate produced by the action of Bacillus pasteurii is formed by the interface between the aggregate and the cement paste, and it spreads over the entire fracture surface and then accumulates to a certain thickness to form a crack repairing effect. The analysis results of the XRD test also clearly confirm that the white crystal formed in the concrete crack is calcium carbonate. From the above test results, it is indeed feasible to use Bacillus pasteurii in the self-healing of concrete cracks.

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.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

scholarly journals Preliminary research for identification of bacteria useful in microbially induced calcium carbonate precipitation

2018 ◽  
Vol 44 ◽  
pp. 00115
Author(s):  
Katarzyna Misiołek ◽  
Paweł Popielski ◽  
Katarzyna Affek
Keyword(s):  
Calcium Carbonate ◽  
Soil Stabilization ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Construction Sites ◽  
Calcite Precipitation ◽  
Strength Parameters ◽  
Gram Staining ◽  
Identification Of Bacteria

MICP (Microbially Induced Calcite Precipitation) is a new biological method in soil stabilization. This cheap and eco-friendly technique improves strength parameters of the ground such as shear strength and decreases the permeability of gravelly and sandy soil. There are variety of microorganisms that can be used in calcite precipitation. The most popular method is precipitation of calcium carbonate by bacteria. The main purpose of the article is to present the results from Gram staining of bacteria isolated from construction sites, which is the first step of their identification. Gram’s method allows to find out which morphological groups of bacteria are adapted to conditions present in soil from construction sites and therefore are potentially able to produce calcite. The article describes the methodology of isolation, staining and determination of morphological types of bacteria.

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