CRACK HEALING EFFICIENCY OF BACTERIA INDUCED CONCRETE (original) (raw)
Related papers
Bacteria-Based concrete crack healing: A review of crack healing effecting factors and size
Nucleation and Atmospheric Aerosols, 2022
It is well-known how water contaminants affect the durability of concrete and cracked concrete are even more exposed to these contaminants. A technique to achieve self-initiating self-healing of cracked concrete is the incorporation of microbial calcite disposition. This technique makes use of the organic activities of bacteria in reaction with additional minerals and compounds to form a sealing compound, commonly calcite. This research serves as a review of previous and ongoing research on the topic of self-healing concrete using bacteria and how it affects and is affected by factors such as the concrete mix proportions and how calcium salts, bacterial nutrients, urea, yeast extract, sugars, sodium, proteins, buffer solutions, humidity and concrete surface treatment affect properties such as setting, hardening and carbonation in addition to reviewing the methodologies used to deal with relatively large cracks via sporulation and vascular networks. The review shows the significance of Ph and porosity of concrete on the survivability of the bacterial cells in addition to the necessity of encapsulation of said cells. Calcium lactate, sodium, proteins and trisaminomethane proved to all aid bacterial growth and the hydration process. Optimum temperature and humidity for self-healing were also pointed out in addition to the effects of self-healing on the water absorption and rates of carbonation during the surface treatment process. Past research on self-healing concrete using bacteria has been reviewed within this paper in relation to the complications that may occur during the setting, hardening, and carbonation of concrete in addition to addressing the issue of healing large cracks.
Advances in Civil Engineering
The most commonly used building material in the construction industry is concrete. However, the weak features of concrete are its low ductility and limited tension capacity and hence crack development with the increase in load. These cracks get more worsened by the intrusion of water and salt present in the composition and hence causing deterioration and reducing the longevity of the material. This study focuses on an innovative approach to mitigate concrete’s fractures and flaws by utilizing microbiologically induced calcite (CaCO3) precipitation (MICP) excited by Escherichia coli (E. coli) bacteria to improve the performance of cementitious building materials. The study investigated the development of microbiological concrete in plain water using only one culture density (OD600 0.5 ± 0.1). In this study, two water-to-bacterial mix ratios (75 : 25 and 50 : 50) were used and compared to the conventional concrete (100 : 0). 100-mm cube-sized specimens cured for a period of 7, 28, 90,...
New Bacterial Concrete to Repair Cracks Through Self Healing Technique
International Journal of Engineering Research and, 2020
Cracks in concrete are unpreventable and it is intrinsic weakness of concrete. Through these cracks water and salts can seep. It initiates corrosion further reducing the life of concrete. So there was a requirement to develop an intrinsic biomaterial, a self repairing technique which can repair the cracks and fissures developed in concrete. This technique is highly desirable because the activity of crack remediation is eco friendly and natural. The paper discusses the plugging of artificial cracks in in cement concrete using Bacillus megaterium. The effect on compressive strength, water absorption and water permeability of cement concrete cubes due to mixing of bacteria is also discussed in this paper. It was found that the use of Escherichia coli improves the compressive strength and stiffness of concrete. The effect on compressive strength, water absorption and water permeability of cement concrete cubes due to mixing of bacteria is also discussed in this paper. It was found that the use of Escherichia coli improves the compressive strength and stiffness of concrete. It also shows that there is reduction in water absorption and water permeability when compared to conventional concrete. The bacteria which are going to be introduced in concrete should have the properties of alkali resistance and it also should form endospore, so that it can withstand the stresses produced in concrete while mixing, handling and transporting.
Crack Healing Utilising Bacterial Spores in Concrete
Journal of Green Building, 2017
This self repair system is based upon harmless ground borne bacteria as the self-healing agent. The bacteria are activated after the concrete is cracked and the bacterial spores are exposed to moisture and air. The bacterial reproduction process creates a calcite by-product which fills the cracks in the concrete. By sealing the cracks in concrete, an effective barrier to air or liquid borne deleterious materials are formed and as a consequence of this, enhanced durability is achieved in the structure, resulting in lower life cycle costs. The concrete/mortar prisms were cracked and tested for water flow. They were then left for 56 days to heal and were subject to a test for water tightness. Healing was observed and a reduced water flow (74% and 32% healed) measured with the healed samples when compared to the specimens that were cracked and subjected to a water flow test without any healing agent. The number of samples were limited and a larger scale test is recommended for further w...
Research on Bacterial Concrete
2016
Micro-cracks are the main cause to structural failure. One way to circumvent costly manual maintenance and repair is to incorporate an autonomous self -healing mechanism in concrete. One such an alternative repair mechanism is currently being studied, i.e. a novel technique based on the application of biomineralization of bacteria in concrete. The applicability of specifically calcite mineral precipitating bacteria for concrete repair and plugging of pores and cracks in concrete has been recently investigated and studies on the possibility of using specific bacteria as a sustainable and concrete –embedded self healing agent was studied and results from ongoing studies are discussed. Synthetic polymers such as epoxy treatment etc. are currently being used for repair of concrete are harmful to the environment, hence the use of a biological repair technique in concrete is focused. Recently, it is found that microbial mineral precipitation resulting from metabolic activities of favourab...
EXPERIMENTAL INVESTIGATION ON SELF-HEALING BACTERIAL CONCRETE
The service life of the structure have reduced in today's construction field due to the low durability, strength factors and various other properties of concrete structures exposed to the environment. A novel strategy to restore or remediate cracks formed in the structures is bio-mineralization of Calcium Carbonate using microbes such as Bacillus. This research gives the information about increasing the durability of the concrete structure by introducing bacterial cell and other required nutrients for the process of bio-calcification where the microorganisms secrete Calcium Precipitate which in the presence of Carbonate ion forms Calcium Carbonate(Calcite) layer thus self-healing the cracks. Thus the durability of the concrete structure will increase and a study has to be carried out with concrete cubes subjected to bacterium.
Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures, 2015
Self-healing concrete has been the subject of great scientific interest over the last ten years. Various research groups worldwide have been working on different healing agent concepts, with bacteria-based healing agents being one of the most popular. Bacterial spores together with organic mineral precursor compounds are immobilized and protected in capsules. Once a crack is created, the bacterial spores turn from a dormant to an active state and start to metabolize the organic compounds, resulting in the production of calcium carbonate crystals. Those crystal formations are able to bridge the open cracks. Many studies have proven the enhanced healing performance of bacteria-based self-healing cementitious materials in comparison to the ordinary ones. However, they do not explicitly designate which performance conditions should be satisfied in order to verify the functionality of the embedded healing agent. This study presents and explains why there are three requirements needed to ensure the performance of a bacteria-based healing agent. Those requirements are the presence of mineral formation inside the crack, the reduced crack permeability and the evidence of bacterial activity in the mortar. In this study, the requirements are studied on mortar specimens through: i) microscopic observations on crystals found inside the cracks, ii) crack water permeability tests and iii) oxygen concentration measurements.
Bacterial Concrete: New Era For Construction Industry
2013
Micro-cracks are the main cause to structural failure. One way to circumvent costly manual maintenance and repair is to incorporate an autonomous self -healing mechanism in concrete. One such an alternative repair mechanism is currently being studied, i.e. a novel technique based on the application of bio- mineralization of bacteria in concrete. The applicability of specifically calcite mineral precipitating bacteria for concrete repair and plugging of pores and cracks in concrete has been recently investigated and studies on the possibility of using specific bacteria as a sustainable and concrete -embedded self-healing agent was studied and results from ongoing studies are discussed. Synthetic polymers such as epoxy treatment etc. are currently being used for repair of concrete are harmful to the environment, hence the use of a biological repair technique in concrete is focused. Recently, it is found that microbial mineral precipitation resulting from metabolic activities of favour...
Bacteria-based self-healing concrete: Effects of environment, exposure and crack size
2016
The effect of water-borne contaminants on the durability of concrete is well-known and cracked concrete is more susceptible to permeation of these contaminants. An approach to autonomic self-healing of such concretes is the utilization of microbiologically-induced calcite-precipitation. This approach uses the metabolic activity of bacteria and biomineral precursors embedded within the concrete to form an inorganic material, usually calcite, as the healing compound. However, bacteria-based healing of concrete creates a number of scientific and engineering challenges at the biology-concrete technology interface. This paper provides a review of previous and on-going research on the use of bacteria-based self-healing of concrete in relation to the problems associated with the setting, hardening and carbonation of concrete and the problems associated with healing large cracks.
Improvement Properties of Self -Healing Concrete by Using Bacteria
2019
The aim of this investigation, self-healing of cracks in concrete by using named Bacillus Subtilis bacteria isolated from agricultural soils and dry soil. Four concrete mixes include, one plain mix without bacteria, other mixes containing a different concentrations of bacteria 10 3 , 10 6 and 10 9 cell/ml respectively were prepared. Hardened properties of concrete water absorption, ultrasonic plus velocity, and compressive strength at 7, 28, 60 and 90 days. Also concrete specimens applied to load 10% of compressive strength at 28 days were studied. The result indicate there is decrease in water absorption of (15-38)%, as well as the decrease in the concrete specimens of loading 10% of compressive strength of (23-41%) relative to control concrete. Increase in compressive resistance of concretes specimens of (6-20)%, (6-17)%, (8-22)% and (7-20)% for ages 7, 28, 60 and 90 days respectively, concrete specimens loaded by 10% of compressive strength, increased by (25-34%) and (34-39%) for 60 and 90 days relative to control concrete. It was observed that the UPV test of concrete specimens was increased. Scanning Electron Micrographic gave an increased in density, deposition of calcite carbonates in the voids and closure of the crack by precipitation of calcium carbonate layers was observed.