scholarly journals Self-healing mortar using different types, content, and concentrations of bacteria to repair cracks.

2021 ◽  
Vol 16 (59) ◽  
pp. 486-513
Author(s):  
Mohamed Ahmed Refat El-Mahdy ◽  
Ahmed ELShami ◽  
Mohamed Yousry Elshikh ◽  
Seleem Saleh Elsayed Ahmad
Keyword(s):  
Bacillus Megaterium ◽  
Bending Strength ◽  
Bacillus Sphaericus ◽  
Alginate Beads ◽  
Self Healing ◽  
Structural Failure ◽  
Significant Development ◽  
Colony Forming Units ◽  
The Cost ◽  
Strength And Durability

The creation of cracks, which are the most common cause of structural failure, has a significant impact on the structure's strength and durability. As a result, effective repair and maintenance are vital and unavoidable for treating any of these issues. Self-healing mortar holds promising benefits for reducing the cost of repair as cracks are autonomously repaired without any human intervention. This study investigated the effect of bacteria type, bacteria content, bacteria concentration, and nutrient type on the properties of the self-healing mortar. Three types of bacteria, Bacillus sphaericus, Bacillus Megaterium, and Bacillus subtilis encapsulated in calcium alginate beads, were introduced into the mortar. Two concentrations of bacteria, 2× 108 and   2× 109 Colony Forming Units per milliliter, and different percentages of bacteria of cement weight were selected for the study. In addition, calcium lactate and calcium acetate were used at 0.5% of cement weight as nutrition for bacteria. Tests were performed for compressive strength, bending strength, SEM, EDX, and TGA/DTG. The results show a significant development in the mechanical behaviour of mortar, especially with Bacillus Megaterium using a 2.5% bacterial proportion with a concentration 2× 109 CFU/ml. This can be related to the filling of voids and cracks in microbial mortar by calcite, which was confirmed by SEM and EDX.

Mechanical and Microstructure Study of the Self Healing Bacterial Concrete

2019 ◽  
Vol 969 ◽  
pp. 472-477
Author(s):  
Sachin Tiwari ◽  
Shilpa Pal ◽  
Rekha Puria ◽  
Vikrant Nain ◽  
Rajendra Prasad Pathak
Keyword(s):  
Compressive Strength ◽  
Bacillus Megaterium ◽  
Construction Material ◽  
Research Work ◽  
Bacillus Sphaericus ◽  
Maximum Amount ◽  
The Self ◽  
Self Healing ◽  
Scanning Electron ◽  
Bacterial Concrete

Concrete largely used for construction material, degrades with the development of cracks that becomes easy passage for entry of chemicals and harmful compounds. Self healing capability is helpful to mitigate the deterioration of the concrete structures. This research work focuses on the self healing behaviour and mechanical properties of the bioconcrete supplemented with three different bacteria namely Bacillus sphaericus, Bacillus cohnii and Bacillus megaterium. Concrete supplemented with Bacillus cohnii exhibited 35.31% increase in compressive strength compared to control mix after 28 days. Concrete supplemented with other bacteria Bacillus sphaericus and Bacillus megaterium also showed enhanced compressive strength. Interestingly, addition of bacteria aided in healing of artificially generated cracks by formation of CaCO3 minerals. Maximum amount of healing (bacterial precipitation) which could be quantified as calcite minerals present in the bacterial concrete was 11.44% with B. cohnii confirmed by the Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDS).

scholarly journals Effect of Bacteria Inoculums on Compressive Strength

2021 ◽  
Vol 8 (2) ◽  
pp. 59-63
Author(s):  
Pooja Bandekar ◽  
Sandhay Basavaraj ◽  
Prakash Mallappa Munnoli ◽  
Jyoti Gupta ◽  
Geeta Shetteppanavar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Culture Collection ◽  
Self Healing ◽  
Cement Concrete ◽  
Calcite Precipitation ◽  
Chain Reaction ◽  
Colony Forming Units ◽  
Polymerase Chain ◽  
Strength And Durability

The use of bio-concrete is increasing in the present day context and researchers are working on strength and durability characteristics of concrete using bacteria species which have shown calcite precipitation. Three different species of bacteria namely P. Fluorescence, B. Pumilis and B. Subliis that have calcite precipitation properties have been investigated in this study. The investigations were carried first on cement mortar (CM) cubes using these three bacteria species suspension of 20%; 40% and 60% having colony forming units P. Fluorescence (108 CFU/ml), B. Pumilis (106 CFU/ml) and B. Subtilis (108 CFU/ml) respectively. The 40% suspension in all the three cases has shown increased compressive strength as compared to 20% and 60%. The compressive strength measured showed increase (CS) of 18%; 12% for P. Fluorescence; B. Subtilis and decrease of 35% with B. Pumilis respectively. B. Subtilis with optimized 40% suspension having CFU 10x108/ml showed 4.32% ; 5.56%; and 3.81% increase in CS of CC cubes with 3 days; 7 days and 28 days respectively and 5.92% overall increase in CS of CC cubes as compared to the 3 days CS of control cube. ABBREVIATIONSSDW: Sterile Distilled Water; SHC: Self-Healing Concrete; PCR: Polymerase Chain Reaction; BC: Bacterial Concrete; CP: Calcite precipitation; CS: Compressive Strength; CC: Cement Concrete; CM: Cement Mortar; MTCC: Microbial Type Culture Collection; CFU: Colony Forming Unit/ml

scholarly journals Self Healing of Microcracks in linings of Irrigation Canal Using Coir Fibre Reinforced Bio-Concrete

2019 ◽  
Vol 8 (11) ◽  
pp. 3275-3280 ◽  
Keyword(s):  
Bacillus Megaterium ◽  
Crack Width ◽  
The Self ◽  
Irrigation Canal ◽  
Self Healing ◽  
Crack Healing ◽  
Compression Tests ◽  
Calcite Precipitation ◽  
Coir Fibre ◽  
Strength And Durability

Development of cracks in the concrete leads to mitigation of the strength and durability of the concrete structures. This paper deals with the application of self-healing concrete for an irrigation canal in a village near Erode. The selfhealing of concrete is a result of calcite precipitation by bacteria (Bacillus Megaterium MTCC 3353) mixed with natural fibres. Here, the compressed soil made irrigation canal which has been used by the farmers for agricultural purpose over a century was lined with the self-healing concrete in order to reduce the evaporation and infiltration of water into the soil thereby improving and increasing the functionality yield of the canal. A controlled crack width is assured by means of the fibres used which substantially increase the tensile capacity of the concrete. The properties of the fibre reinforced bio-concrete was evaluated by conducting flexural and compression tests along with study of amount of crack-healing in concrete with and without the use of bacteria.

scholarly journals Calcium/Cobalt Alginate Beads as Functional Scaffolds for Cartilage Tissue Engineering

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Stefano Focaroli ◽  
Gabriella Teti ◽  
Viviana Salvatore ◽  
Isabella Orienti ◽  
Mirella Falconi
Keyword(s):  
Tissue Engineering ◽  
Bone Morphogenetic Proteins ◽  
Transforming Growth Factor ◽  
Cartilage Tissue Engineering ◽  
Biomechanical Properties ◽  
Alginate Beads ◽  
Cartilage Tissue ◽  
Self Healing ◽  
Tissue Replacement

Articular cartilage is a highly organized tissue with complex biomechanical properties. However, injuries to the cartilage usually lead to numerous health concerns and often culminate in disabling symptoms, due to the poor intrinsic capacity of this tissue for self-healing. Although various approaches are proposed for the regeneration of cartilage, its repair still represents an enormous challenge for orthopedic surgeons. The field of tissue engineering currently offers some of the most promising strategies for cartilage restoration, in which assorted biomaterials and cell-based therapies are combined to develop new therapeutic regimens for tissue replacement. The current study describes thein vitrobehavior of human adipose-derived mesenchymal stem cells (hADSCs) encapsulated within calcium/cobalt (Ca/Co) alginate beads. These novel chondrogenesis-promoting scaffolds take advantage of the synergy between the alginate matrix and Co+2ions, without employing costly growth factors (e.g., transforming growth factor betas (TGF-βs) or bone morphogenetic proteins (BMPs)) to direct hADSC differentiation into cartilage-producing chondrocytes.

Predicting effects of selected impregnation processes on the observed bending strength of wood, with use of data mining models

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4891-4904
Author(s):  
Selahattin Bardak ◽  
Timucin Bardak ◽  
Hüseyin Peker ◽  
Eser Sözen ◽  
Yildiz Çabuk
Keyword(s):  
Data Mining ◽  
Goodness Of Fit ◽  
Bending Strength ◽  
Wood Preservation ◽  
Ambient Conditions ◽  
Data Mining Algorithms ◽  
Use Of Data ◽  
The Cost ◽  
Mining Algorithms ◽  
The Relationship

Wood materials have been used in many products such as furniture, stairs, windows, and doors for centuries. There are differences in methods used to adapt wood to ambient conditions. Impregnation is a widely used method of wood preservation. In terms of efficiency, it is critical to optimize the parameters for impregnation. Data mining techniques reduce most of the cost and operational challenges with accurate prediction in the wood industry. In this study, three data-mining algorithms were applied to predict bending strength in impregnated wood materials (Pinus sylvestris L. and Millettia laurentii). Models were created from real experimental data to examine the relationship between bending strength, diffusion time, vacuum duration, and wood type, based on decision trees (DT), random forest (RF), and Gaussian process (GP) algorithms. The highest bending strength was achieved with wenge (Millettia laurentii) wood in 10 bar vacuum and the diffusion condition during 25 min. The results showed that all algorithms are suitable for predicting bending strength. The goodness of fit for the testing phase was determined as 0.994, 0.986, and 0.989 in the DT, RF, and GP algorithms, respectively. Moreover, the importance of attributes was determined in the algorithms.

Self‐Healing of Cracks in Concrete Using Bacillus Strains Encapsulated in Sodium Alginate Beads

2020 ◽  
Vol 5 (1) ◽  
pp. 312-323 ◽  
Author(s):  
Saman Shahid ◽  
Muhammad A. Aslam ◽  
Shahid Ali ◽  
Mariam Zameer ◽  
Muhammad Faisal
Keyword(s):  
Sodium Alginate ◽  
Alginate Beads ◽  
Self Healing ◽  
Bacillus Strains

Study of the Physical and Mechanical Characteristics of the Ice Cover

2019 ◽  
Vol 974 ◽  
pp. 482-487
Author(s):  
A.S. Vasilyev ◽  
V.L. Zemlyak ◽  
V.M. Kozin
Keyword(s):  
Mechanical Characteristics ◽  
Bending Strength ◽  
Winter Season ◽  
Physical And Mechanical Properties ◽  
Ice Cover ◽  
The Arctic ◽  
Structural Failure ◽  
Extreme North ◽  
Far Eastern ◽  
Physical And Mechanical Characteristics

The construction of crossing ferry landings across the Arctic Shelf and the regions located in the Extreme North or Far North, as well as the Siberian and Far Eastern rivers during the winter season is a difficult task of immediate concern. Nevertheless, it is necessary to learn the ice mechanical characteristics in order to examine the bearing capacity of the ice cover at the crossing ferry landings aimed at their establishment and strengthening. The purpose of the paper is to observe the physical and mechanical features of the ice cover by means of doing simulated experiments and verifying their validity using a computational model. The research performed the studies on Young’s modulus of ice definition and bending strength. Ice beam samples were used in the simulated experiments. Their physical and mechanical properties were put to the tests carried out with a special loading device. There was a structural failure of ice beam samples influenced by pure bending. The authors performed numerical computations on the ground of the data obtained by ANSYS software. The calculations resulted in determining condition of the stress-strain state of the samples at any time of loading up to their complete breaking-up. The efficiency of the algorithm is proved by comparing numerical calculations to simulated experimental data.

A probabilistic approach for design and certification of self-healing advanced composite structures

2011 ◽  
Vol 225 (4) ◽  
pp. 435-449 ◽  
Author(s):  
H R Williams ◽  
R S Trask ◽  
I P Bond
Keyword(s):  
Composite Structures ◽  
High Performance ◽  
Probabilistic Approach ◽  
Healing Time ◽  
Self Healing ◽  
Structural Failure ◽  
Healing System ◽  
Order Of Magnitude ◽  
Damage Tolerant

Design and certification of novel self-healing aerospace structures was explored by reviewing the suitability of conventional deterministic certification approaches. A sandwich structure with a vascular network self-healing system was used as a case study. A novel probabilistic approach using a Monte Carlo method to generate an overall probability of structural failure yields notable new insights into design of self-healing systems, including a drive for a faster healing time of less than two flight hours. In the case study considered, a mature self-healing system could be expected to reduce the probability of structural failure (compared to a conventional damage-tolerant construction) by almost an order of magnitude. In a risk-based framework this could be traded against simplified maintenance activity (to save cost) and/or increased allowable stress (to allow a lighter structure). The first estimate of the increase in design allowable stresses permitted by a self-healing system is around 8 per cent, with a self-healing system much lighter than previously envisaged. It is thought these methods and conclusions could have wider application to self-healing and conventional high-performance composite structures.

Aggregate Grading and Mechanical Property Study on Particulate-Reinforced Composite

2011 ◽  
Vol 225-226 ◽  
pp. 13-16
Author(s):  
Jian Xiong Xie ◽  
Zhe An Lu
Keyword(s):  
Mechanical Property ◽  
Quartz Sand ◽  
Bending Strength ◽  
Composite Resin ◽  
Resin Content ◽  
Aggregate Gradation ◽  
Reinforced Composite ◽  
The Cost ◽  
Particle Reinforced Composite ◽  
Particulate Reinforced

The aggregate gradation and mechanical property of particle reinforced composite (resin and quartz sand composite ) were studied with test, the results show that: The more optimal scheme of aggregate gradation can be obtained with right ratio of larger particle quartz sand and small particle quartz plate , which can make the gradation resin content from the original 20% ~ 25% reduced to 12% ~ 14%, so as to reduce the cost and improve the economic benefit and guarantee bending strength of winding layer not decrease in the meantime

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