scholarly journals Self‐Healing Engineering Ceramics with Oxidation‐Induced Crack Repair

2019 ◽  
Vol 22 (9) ◽  
pp. 1901121 ◽  
Author(s):  
Peter Greil
Keyword(s):  
Self Healing ◽  
Engineering Ceramics ◽  
Crack Repair

On 3D printing of electro-active PVDF-Graphene and Mn-doped ZnO nanoparticle-based composite as a self-healing repair solution for heritage structures

2021 ◽  
pp. 095440542110609
Author(s):  
Vinay Kumar ◽  
Rupinder Singh ◽  
Inderpreet Singh Ahuja
Keyword(s):  
3D Printing ◽  
Polyvinylidene Fluoride ◽  
Nano Particles ◽  
Zno Nanoparticle ◽  
Self Healing ◽  
Fused Deposition ◽  
Crack Repair ◽  
3D Printed ◽  
Doped Zno ◽  
Mn Doped

Construction is the part of human activity which is directly linked to urbanization for moving ahead on the path of growth and prosperity. Construction activities in past centuries are now part of our precious heritage. The repair and maintenance of heritage structures are of great importance for present-day researchers. One of the most common damage these century-long constructions faces are in form of surface cracks. In the present study, investigations were performed for a 3D printing-based customized solution for crack repair and maintenance of heritage structures. In this study, polyvinylidene fluoride (PVDF) polymer was reinforced with graphene (Gr) and Mn-doped ZnO nano-particles to prepare a smart composite material for crack repair and restoration. The composite was successfully 3D printed on fused deposition modeling (FDM) based 3D printer after investigating its rheological, thermal, and mechanical properties. The in-house developed composite was tested for smart characteristics to use as a programmable solution for filling cracks. The piezoelectric property and dielectric constant of 3D printed disk-shaped composite (PVDF-Gr-Mn-ZnO) were obtained after DC poling (to be used as stimulus) of the functional prototype. The results of the study suggest that the electro-active nature, volumetric change, and charge storing capacity of the additively manufactured composite may be used practically to acquire the shape of cavity/crack present in the constructed wall and repair the damages that occurred in a heritage site. The photoluminescence (PLS) and atomic force microscopy (AFM) analysis was used to ascertain the properties of the prepared composite. Also, the results obtained from the morphological analysis are reported to support the outcomes of the research.

scholarly journals Feasibility and Compatibility of a Biomass Capsule System in Self-Healing Concrete

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 958
Author(s):  
Arkabrata Sinha ◽  
Qi Wang ◽  
Jianqiang Wei
Keyword(s):  
Strength Degradation ◽  
Survival Ratio ◽  
Self Healing ◽  
Crack Healing ◽  
Mortar Strength ◽  
Concrete Properties ◽  
Promising Strategy ◽  
Healing Efficiency ◽  
Biomass Component ◽  
Crack Repair

Cracking can facilitate deteriorations of concrete structures via various mechanisms by providing ingress pathways for moisture and aggressive chemicals. In contrast to conventional maintenance methods, self-healing is a promising strategy for achieving automatic crack repair without human intervention. However, in capsule-based self-healing concrete, the dilemma between capsules’ survivability and crack healing efficiency is still an unfathomed challenge. In this study, the feasibility of a novel property-switchable capsule system based on a sustainable biomass component, polylactic acid, is investigated. Capsules with different geometries and dimensions were studied focusing on the compatibility with concrete, including survivability during concrete mixing, influence on mortar and concrete properties, and property evolution of the capsules. The results indicate that the developed elliptical capsules can survive regular concrete mixing with a survival ratio of 95%. In concrete containing 5 vol.% of gravel-level capsules, the compressive strength was decreased by 13.5% after 90 days, while the tensile strength was increased by 4.8%. The incorporation of 2 vol.% of sand-level capsules did not impact the mortar strength. Degradation and switchable properties triggered by the alkaline matrix of cement were observed, revealing the potential of this novel biomass capsule system in achieving both high survivability and self-healing efficiency in concrete.

scholarly journals Comparison of Microbially Induced Healing Solutions for Crack Repairs of Cement-Based Infrastructure

2021 ◽  
Vol 13 (8) ◽  
pp. 4287
Author(s):  
John Milan van der Bergh ◽  
Bojan Miljević ◽  
Snežana Vučetić ◽  
Olja Šovljanski ◽  
Siniša Markov ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Service Life ◽  
Cementitious Materials ◽  
Bacterial Suspension ◽  
Self Healing ◽  
Construction Costs ◽  
Recovery Processes ◽  
Concrete Crack ◽  
Crack Repair ◽  
Water Absorption Test

Reinforced concrete crack repair and maintenance costs are around 84% to 125% higher than construction costs, which emphasises the need to increase the infrastructure service life. Prolongation of the designed service life of concrete structures can have significant economic and ecological benefits by minimising the maintenance actions and related increase of carbon and energy expenditure, making it more sustainable. Different mechanisms such as diffusion, permeation and capillary action are responsible for the transport of fluids inside the concrete, which can impact on the structure service life. This paper presents data on microbially induced repair and self-healing solutions for cementitious materials available in the contemporary literature and compares results of compressive strength test and capillary water absorption test, which are relevant to their sealing and mechanical characteristics. The results of the repair and self-healing solutions (relative to unassisted recovery processes) were “normalized.” Externally applied bacteria-based solutions can improve the compressive strength of cementitious materials from 13% to 27%. The internal solution based solely on bacterial suspension had 19% improvement efficacy. Results also show that “hybrid” solutions, based on both bio-based and non-bio-based components, whether externally or internally applied, have the potential for best repair results, synergistically combining their benefits.

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.

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 The effect of isolated Bacillus ureolytic bacteria in improving the bio-healing of concrete cracks

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Gehad Mokhtar ◽  
Ahmed Abd-El-Azim Ahmed ◽  
Amany M. Reyad
Keyword(s):  
Compressive Strength ◽  
Bacterial Species ◽  
Concrete Strength ◽  
Self Healing ◽  
Crack Healing ◽  
Bacterial Strains ◽  
Crack Repair ◽  
Critical Problems ◽  
Ureolytic Bacteria ◽  
Chemical Materials

Abstract Background Reinforcement corrosion and the concrete strength reduction are critical problems that resulted from crack creation in concrete. Very expensive and hazardous technologies based on chemical materials have been provided for repairing the cracks. Recently, crack repair using bio-catalysis precipitating bacteria has been developed as a viable and ecofriendly alternative technique. The main target of this study was to select and identify bacterial isolates with high urease activity to use in filling the cracks by the precipitation of CaCO3. Results Two endospore-forming and alkali-resistant ureolytic bacteria were combined with concrete to tolerate the mechanical stresses generated by mixing. The two isolates designated as (B1 and B2) were selected and identified as Bacillus wiedmannii strain FSL W8-0169 and Bacillus paramycoides strain MCCC 1A04098, respectively, using 16SrDNA gene sequencing. Both bacterial species completely heal cracks in fully destructed concrete and significant enhancement in compressive strength was illustrated. The calcite filling of cracks and CaCO3 crystals that were screened using a scanning electron microscope may explain the crack healing and the enhancement in concrete strength. Conclusions Bacillus wiedmannii strain FSL W8-0169 and Bacillus paramycoides strain MCCC 1A04098 can be inserted with the concrete to improve the compressive strength and the self-healing of cracks. The two ureolytic bacterial strains can be used to protect water buildings from exposure to frequent cracks.

scholarly journals BACTERIA BASED SELF-HEALING CONCRETE :A REVIEW

2021 ◽  
Vol 25 (Special) ◽  
pp. 3-43-3-56
Author(s):  
Arej K. Mahmod ◽  
◽  
Lubna A. Al-Jabbar ◽  
Mohammed M. Salman ◽  
◽  
...  
Keyword(s):  
Building Materials ◽  
Current Treatment ◽  
Future Research ◽  
Self Healing ◽  
Treatment Methods ◽  
Environmentally Sustainable ◽  
Research Areas ◽  
Future Challenges ◽  
Crack Repair ◽  
Near Future

Concrete is one of the most commonly used building materials, and which is prone to cracking. The service life of concrete is significantly reduced due to these cracks. Replacement are High costs and difficulties in avoiding the cracks, various methods are in place to prevent crack formation such as filling in the gaps. It has been demonstrated current treatment methods of concrete are Chemical and polymer applications which they are a source of health and environmental issues, and they are only getting worse successful under some situations. As a result, environmentally sustainable treatment methods will be required in the near future. The potential for long-term, rapid, and active crack repair distinguishes the microbial self-healing method, which is also environmentally friendly. in addition, microbial self-healing Thanks to the effectiveness of this procedure, which out performs most treatment methods. Concrete compatibility and effective bonding capability assemblages. This paper gives an overview of the various microbial methods for producing calcium carbonate (CaCO3). Future challenges in microbial crack treatment are discussed, as well as recommendations for future research areas.

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