scholarly journals LAB-SCALE EXPERIMENTS FOR SOIL CEMENTING THROUGH BIO-CHEMICAL PROCESS

2021 ◽  
Vol 11 (4) ◽  
pp. 255-265
Author(s):  
Nguyen Ngoc Tri Huynh ◽  
Tran Anh Tu ◽  
Nguyen Pham Huong Huyen ◽  
Nguyen Khanh Son
Keyword(s):  
Calcium Carbonate ◽  
Soil Stabilization ◽  
Mechanical Stability ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Promising Technique ◽  
Concrete Material ◽  
Moisture Condition ◽  
Water Percolation ◽  
Unconventional Method

Ureolytic bacteria strains of Bacillus show its ability of calcium carbonate precipitation through metabolic activity. Different studies related to self-healing concrete material were reported associated with the generated calcium carbonate of Bacillus subtilis HU58 metabolism in recent communications. In this paper, recent findings of soil cementing with a combination of such precipitated products were presented. The experiments relied on the lab-scale studies with the use of sand-clay mixture as the controlled soil specimens. Bacillus bacteria and nutrients were mixed to introduce in the sand matrix and then curing in high moisture condition. The composition and morphology of soil specimens were characterized after solidifying by FTIR, XRD, and SEM. Water percolation and mechanical stability for the physicomechanical properties were also tested with the unconventional method. Discussing the relevant results can help to figure out the next experiments in the field of geotechnical engineering. From the perspective of this study, the sustainability factor should be considered to apply this promising technique for soil stabilization and improvement and/or for the formulation of bio-brick as an alternative to sintered clay-based brick. From the perspective of this study, this technique for soil stabilization and improvement and/or for the formulation of bio-brick can be considered a promising sustainable alternative to sintered clay-based brick.

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.

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 Experimental Study on MICP Technology for Strengthening Tail Sand under a Seepage Field

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Zhi-jun Zhang ◽  
Biao Li ◽  
Lin Hu ◽  
Huai-miao Zheng ◽  
Gui-cheng He ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Calcium Ion ◽  
Soil Stabilization ◽  
Comparative Experiment ◽  
Penetration Test ◽  
Calcium Carbonate Precipitation ◽  
Ion Content ◽  
Seepage Field ◽  
Main Factor

Microbial-induced calcium carbonate precipitation (MICP) technology is a new green reinforcing technology in soil stabilization. Targeting on the problem that seepage is the main factor of causing the instability of a tailings dam, a comparative experiment is conducted, which includes the MICP technology on reinforcing tailings with or without the effect of a seepage field. The results of the comparative experiment are as follow: the mercury penetration test indicates that, under the function of a seepage field, the total pore in the tailing is relatively decreased; SEM shows that under the function of a seepage field, the intergranular pore increases; the direct shear test shows that under the function of a seepage field, the tailings’ shear strength decreases; the determination of calcium ion content shows that the distribution of calcium carbonate in the tailings under the action of a seepage field is more uneven.

scholarly journals Influence of native ureolytic microbial community on biocementation potential of Sporosarcina pasteurii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Raja Murugan ◽  
G. K. Suraishkumar ◽  
Abhijit Mukherjee ◽  
Navdeep K. Dhami
Keyword(s):  
Microbial Community ◽  
Calcium Carbonate ◽  
Kinetic Analysis ◽  
Microbial Communities ◽  
Slow Rate ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Promising Technique ◽  
Sporosarcina Pasteurii ◽  
The Impact

AbstractMicrobially induced calcium carbonate precipitation (MICP)/Biocementation has emerged as a promising technique for soil engineering applications. There are chiefly two methods by which MICP is applied for field applications including biostimulation and bioaugmentation. Although bioaugmentation strategy using efficient ureolytic biocementing culture of Sporosarcina pasteurii is widely practiced, the impact of native ureolytic microbial communities (NUMC) on CaCO3 mineralisation via S. pasteurii has not been explored. In this paper, we investigated the effect of different concentrations of NUMC on MICP kinetics and biomineral properties in the presence and absence of S. pasteurii. Kinetic analysis showed that the biocementation potential of S. pasteurii is sixfold higher than NUMC and is not significantly impacted even when the concentration of the NUMC is eight times higher. Micrographic results revealed a quick rate of CaCO3 precipitation by S. pasteurii leading to generation of smaller CaCO3 crystals (5–40 µm), while slow rate of CaCO3 precipitation by NUMC led to creation of larger CaCO3 crystals (35–100 µm). Mineralogical results showed the predominance of calcite phase in both sets. The outcome of current study is crucial for tailor-made applications of MICP.

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.

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