scholarly journals The effect of temperature on bacterial self-healing processes in building materials

2020 ◽  
Vol 726 ◽  
pp. 012012
Author(s):  
P Ryparová ◽  
P Tesárek ◽  
H Schreiberová ◽  
Z Prošek
Keyword(s):  
Building Materials ◽  
Effect Of Temperature ◽  
Self Healing ◽  
Healing Processes

Investigating the Effect of Thermoelectric Processing on Ionic Aggregation in Thermoplastic Ionomers

2017 ◽  
Author(s):  
Prasant Vijayaraghavan ◽  
Vishnu-Baba Sundaresan
Keyword(s):  
Mechanical Properties ◽  
Electrostatic Field ◽  
Thermal Studies ◽  
Effect Of Temperature ◽  
Self Healing ◽  
Polymer Backbone ◽  
Ionic Dissociation ◽  
Dissociation Temperature ◽  
Aggregate Morphology ◽  
Poly Ethylene

Ionomers are a class of polymers which contain a small fraction of charged groups in the polymer backbone. These ionic groups aggregate (termed ionic aggregates) to form temporary cross-links that break apart over the ionic dissociation temperature and re-aggregate on cooling, influencing the mechanical properties of these polymers. In addition to enhanced mechanical properties, some ionomers also exhibit self-healing behavior. The self-healing behavior is a consequence of weakly bonded ionic aggregates breaking apart and re-aggregating after puncture or a ballistic impact. The structure and properties of ionomers have been studied over the last several decades; however, there is a lack of understanding of the influence of an electrostatic field on ionic aggregate morphology. Characterizing the effect of temperature and electric field on the formation and structure of these ionic aggregates will lead to preparation of ionomers with enhanced structural properties. This work focuses on Surlyn 8940 which a poly-ethylene methacryclic acid co-polymer in which a fraction of the carboxylic acid is terminated by sodium. In this work, Surlyn is thermoelectrically processed over its ionic dissociation temperature in the presence of a strong electrostatic field. Thermal studies are performed on the ionomer to study the effect of the thermoelectric processing. It is shown that the application of a thermoelectric field leads to increase in the ionic aggregate order in these materials and reduction in crystal size distribution. Thermal Analysis is performed using a Differential Scanning Calorimeter and the resulting thermogram analysis shows that thermoelectric processing increases the peak temperature and onset temperature of melting by 4 C and 20 C respectively. The peak width at half maximum of the melting endotherm is reduced by 10 C due to thermoelectric processing. This serves as a measure of the increased crystallinity. A parametric study on the effect of field duration and field strength is also performed.

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 Creep Properties and Constitutive Model of Salt Rock

2021 ◽  
Vol 2021 ◽  
pp. 1-29
Author(s):  
Qiang Zhang ◽  
Zhanping Song ◽  
Junbao Wang ◽  
Yuwei Zhang ◽  
Tong Wang
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Effect Of Temperature ◽  
Creep Process ◽  
Underground Storage ◽  
Self Healing ◽  
Salt Rock ◽  
Creep Properties ◽  
Term Operation ◽  
Rock Creep

Due to the advantages of low porosity, low permeability, high ductility, and excellent capacities for creep and damage self-healing, salt rock is internationally considered as the ideal medium for underground storage of energy and disposal of radioactive waste. As one of the most important mechanical properties of salt rock, creep properties are closely related to the long-term operation stability and safety of salt rock underground storage cavern. A comprehensive review on the creep properties and constitutive model of salt rock is put forward in this paper. The opinions and suggestions on the research priority and direction of salt rock's mechanical properties in the future are put forward: (1) permeability variation of salt rock under the coupling effect of temperature and stress; (2) damage mechanism and evolution process under the effect of creep-fatigue interaction and low frequency cyclic loading; (3) microdeformation mechanisms of salt rock and the relationship between microstructure variations and macrocreep behavior during creep process; (4) the establishment of the creep damage constitutive model with simple form, less parameters, easy application, and considering the damage self-healing ability of salt rock simultaneously.

Self-Healing Processes in Concrete

2009 ◽  
pp. 141-182 ◽  
Author(s):  
Erk Schlangen ◽  
Christopher Joseph
Keyword(s):  
Self Healing ◽  
Healing Processes

Physico-Chemical Characterisation of Protective Coatings and Self Healing Processes

2016 ◽  
pp. 241-298
Author(s):  
Anthony E. Hughes ◽  
Sam Yang ◽  
Berkem Oezkaya ◽  
Ozlem Ozcan ◽  
Guido Grundmeier
Keyword(s):  
Protective Coatings ◽  
Self Healing ◽  
Physico Chemical ◽  
Healing Processes

scholarly journals Self-Healing Potential of Geopolymer Concrete

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 6
Author(s):  
Rajczakowska ◽  
Habermehl-Cwirzen ◽  
Hedlund ◽  
Cwirzen
Keyword(s):  
Building Materials ◽  
Crack Opening ◽  
Healing Process ◽  
Activation Parameters ◽  
Optical Microscope ◽  
Bending Test ◽  
Geopolymer Concrete ◽  
Self Healing ◽  
Lime Water ◽  
Activated Slag

Waste management is emerging as one of the most troublesome and critical problems of the upcoming decades. Therefore, the utilization of industrial by-products as building materials components has been widely studied in recent years. Geopolymer concrete, with binder entirely substituted by slag or fly ash, is one of the materials, which combines positive environmental impact with satisfying mechanical parameters. Although various properties of geopolymers have been examined, the autogeneous self-healing potential of this alternative binder has not been thoroughly verified yet. This paper aims to validate whether geopolymer concrete made of alkali activated slag is capable of self-repair. Four different mortar mixes with two types of slag and varying activation parameters were investigated. The polyvinyl alcohol (PVA) fibers were added in order to control the crack width. The 1.2 × 1.2 × 6 cm beams were pre-cracked with the use of three point bending test at 7 days after casting to achieve crack opening of approximately 300 µm. The effects of various exposure conditions on the healing process were examined, i.e., lime water, different sodium silicate solutions and water. The self-healing efficiency as well as the evolution of the crack recovery was assessed by the observation of the crack surface with the use of digital optical microscope. The healed area of the crack was calculated and compared for all the specimens by applying the image processing techniques. The morphology of the healing products as well as their chemical composition were examined with the use of Scanning Electron Microscope with Energy Dispersive Spectroscopy.

Progress in the remote-controlled activation of self-healing processes

2016 ◽  
Vol 25 (8) ◽  
pp. 084018 ◽  
Author(s):  
Ahmad Shaaban ◽  
Annette M Schmidt
Keyword(s):  
Self Healing ◽  
Healing Processes

Modeling Self-Healing Processes in Polymers: From Nanogels to Nanoparticle-Filled Microcapsules

2013 ◽  
pp. 91-111
Author(s):  
German V. Kolmakov ◽  
Isaac G. Salib ◽  
Anna C. Balazs
Keyword(s):  
Self Healing ◽  
Healing Processes
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