Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337906001
Natacha Daoud, C. Breysse, S. Domenek, O. Vitrac
European and national environmental protection policies have programmed the forthcoming end of single-use plastics, including food packaging. Because plastic materials account for 50% of plastic waste, closed-loop recycling seems imperative. Still, plastics other than PET (Polyethylene terephthalate) are not widely recycled for food contact due to safety concerns. Among them, postconsumer polyolefins are heavily formulated, degraded, and contaminated by the previously contacting product. Using recycled materials behind a functional barrier (FB) could resolve the issue under specific provisions, but neither the European regulation nor the US FDA offer guidance concerning functional barriers evaluation and use. Mathematical modeling is the only viable method recognized by European and American agencies to evaluate recycled material under usage conditions. This study numerically explores the possibility of combining two effects: decontamination of the recycled material and a functional barrier to allow safe use of the recycled material.
{"title":"Time of protection equivalence principle to allow design barrier layers for promoting the use of recycled materials for food contact","authors":"Natacha Daoud, C. Breysse, S. Domenek, O. Vitrac","doi":"10.1051/matecconf/202337906001","DOIUrl":"https://doi.org/10.1051/matecconf/202337906001","url":null,"abstract":"European and national environmental protection policies have programmed the forthcoming end of single-use plastics, including food packaging. Because plastic materials account for 50% of plastic waste, closed-loop recycling seems imperative. Still, plastics other than PET (Polyethylene terephthalate) are not widely recycled for food contact due to safety concerns. Among them, postconsumer polyolefins are heavily formulated, degraded, and contaminated by the previously contacting product. Using recycled materials behind a functional barrier (FB) could resolve the issue under specific provisions, but neither the European regulation nor the US FDA offer guidance concerning functional barriers evaluation and use. Mathematical modeling is the only viable method recognized by European and American agencies to evaluate recycled material under usage conditions. This study numerically explores the possibility of combining two effects: decontamination of the recycled material and a functional barrier to allow safe use of the recycled material.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81471820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337907005
Ronny Gueguen, Guillaume Sahuquet, S. Mer, A. Toutant, Françoise Bataille, G. Flamant
The concept of solar receiver using fluidized particles as heat transfer fluid is attractive from the point of view of its performance but also of the material used. In this concept, the receiver is composed of tubes subjected to concentrated solar radiation in which the fluidized particles circulate vertically. Circulation in the tubes, immersed in a “nurse” fluidized bed, is ensured thanks to a controlled pressure difference imposed on the latter and secondary aeration. This ventilation located at the bottom of the absorber tubes makes it possible to control the fluidization regimes. The latter strongly influence the parietal heat transfers and therefore the performance of the receiver. In order to better understand the conditions of appearance of these regimes and to better identify them, a study at room temperature was carried out with a tube 45 mm in internal diameter and 3.63 m in height. The tube is instrumented with several pressure sensors distributed over its height. More than 170 experiments have been performed exploring wide ranges of particle and aeration flow rates, with and without particle circulation. Signal processing methods, classically used in the scientific literature of fluidized beds, are applied. Combined together, these methods have enabled the identification of bubbling, pistoning (of the wall and axisymmetric), turbulent fluidization and rapid fluidization regimes. The pooling of all this information allows the establishment of a diagram of the fluidization regimes and their transition, showing that the local slip velocity is the key parameter governing the structure of the flow.
{"title":"Experimental Study of an upflow Fluidized Bed: Identification of Fluidization Regimes","authors":"Ronny Gueguen, Guillaume Sahuquet, S. Mer, A. Toutant, Françoise Bataille, G. Flamant","doi":"10.1051/matecconf/202337907005","DOIUrl":"https://doi.org/10.1051/matecconf/202337907005","url":null,"abstract":"The concept of solar receiver using fluidized particles as heat transfer fluid is attractive from the point of view of its performance but also of the material used. In this concept, the receiver is composed of tubes subjected to concentrated solar radiation in which the fluidized particles circulate vertically. Circulation in the tubes, immersed in a “nurse” fluidized bed, is ensured thanks to a controlled pressure difference imposed on the latter and secondary aeration. This ventilation located at the bottom of the absorber tubes makes it possible to control the fluidization regimes. The latter strongly influence the parietal heat transfers and therefore the performance of the receiver. In order to better understand the conditions of appearance of these regimes and to better identify them, a study at room temperature was carried out with a tube 45 mm in internal diameter and 3.63 m in height. The tube is instrumented with several pressure sensors distributed over its height. More than 170 experiments have been performed exploring wide ranges of particle and aeration flow rates, with and without particle circulation. Signal processing methods, classically used in the scientific literature of fluidized beds, are applied. Combined together, these methods have enabled the identification of bubbling, pistoning (of the wall and axisymmetric), turbulent fluidization and rapid fluidization regimes. The pooling of all this information allows the establishment of a diagram of the fluidization regimes and their transition, showing that the local slip velocity is the key parameter governing the structure of the flow.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82687371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337807004
S. Rengaraju, C. Vlachakis, Vahid Afroughsabet, A. Al-Tabbaa
Prolonging the life of the reinforced concrete structure is the most promising solution to reduce the carbon emissions from concrete. To achieve that, the structure should be protected from crack formation, which acts as an easy pathway for deleterious agents. Self-healing technologies are intended to provide long-term resilience against cracking due to various deterioration processes. Technologies that performed well in small, laboratory-scale studies are taken to the next level to assess their performance on a larger scale and monitored using various NDT equipment. A 1m long beam with a cross-section (140×120 mm) was cast with two rebars – one with a cover depth of 50 mm from the top and another with a cover depth of 20 mm from the bottom. The mix design consists of CEM IIIA (50 OPC: 50 Slag) cement and 30% lightweight aggregate as a replacement for coarse aggregate. At 28 days of curing, the concrete beams are subjected to accelerated corrosion (by applying a voltage to the bottom rebar) to induce internal cracking. Once internal cracking is induced, the beams are subjected to another 28 days under water for healing. The performance of the beams is monitored via ultrasonic pulse velocity and half-cell potential before and after voltage application. This paper shows the preliminary results and the self-healing efficiency and corrosion resistance of these beams are continuously being monitored under severe chloride conditions to predict the long-term performance.
{"title":"Large-Scale Laboratory Trials of Self-Healing Technologies","authors":"S. Rengaraju, C. Vlachakis, Vahid Afroughsabet, A. Al-Tabbaa","doi":"10.1051/matecconf/202337807004","DOIUrl":"https://doi.org/10.1051/matecconf/202337807004","url":null,"abstract":"Prolonging the life of the reinforced concrete structure is the most promising solution to reduce the carbon emissions from concrete. To achieve that, the structure should be protected from crack formation, which acts as an easy pathway for deleterious agents. Self-healing technologies are intended to provide long-term resilience against cracking due to various deterioration processes. Technologies that performed well in small, laboratory-scale studies are taken to the next level to assess their performance on a larger scale and monitored using various NDT equipment. A 1m long beam with a cross-section (140×120 mm) was cast with two rebars – one with a cover depth of 50 mm from the top and another with a cover depth of 20 mm from the bottom. The mix design consists of CEM IIIA (50 OPC: 50 Slag) cement and 30% lightweight aggregate as a replacement for coarse aggregate. At 28 days of curing, the concrete beams are subjected to accelerated corrosion (by applying a voltage to the bottom rebar) to induce internal cracking. Once internal cracking is induced, the beams are subjected to another 28 days under water for healing. The performance of the beams is monitored via ultrasonic pulse velocity and half-cell potential before and after voltage application. This paper shows the preliminary results and the self-healing efficiency and corrosion resistance of these beams are continuously being monitored under severe chloride conditions to predict the long-term performance.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82564591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337805001
Gabriele Milone, J. Tulliani, A. Al-Tabbaa
Sensing coatings are rapidly entering the field of non-destructive tests. While cement-based composites are proving an excellent interaction with new/recent structures, polymer-based coatings, already employed for structural retrofitting purposes, can provide a valuable alternative. This study investigated the production, application, and use of poly(vinylidene fluoride) (PVDF) coatings. A 10w/v% PVDF-to-solvent ratio became the best trade-off between electrical conductivity and bond strength with the substrate. Different concentrations of Carbon Nanotubes (CNT) were investigated: 0.05, 0.10, 0.25, 0.50, and 0.75% by weight of PVDF. The conductive PVDF-CNT composites were brushed on the casted mortar beams with screws embedded as electrodes. The mortar beams and attached polymer coatings were then subjected to bending stress. The Gauge Factor was obtained by comparing the substrate’s strain with the coating’s electric response. The sensing intervals in the Fractional Change of Resistance-strain curves varied in relation to the CNT concentration. For instance, adding 0.50w/v% of CNT gave the highest sensitivity up to 0.2‰ strain, followed by a lower – still sufficient – gauge factor. PVDF-based coatings with CNT additions of 0.25 and 0.75w/v% witnessed a comparable sensing performance in the same strain limits, abruptly increasing and finally stabilizing to a low gauge factor. In contrast, both 0.05 and 0.10w/v% resulted in a low monitoring potential overall. The varying sensing zones experienced by the coating were attributed to the microscopical behavior of CNT within the PVDF matrix. In conclusion, the results highlighted the potentiality of polymeric coatings for sensing, monitoring, and inspection of concrete structures.
{"title":"PVDF-based coatings with CNT additions for strain monitoring of mortar substrates subjected to bending","authors":"Gabriele Milone, J. Tulliani, A. Al-Tabbaa","doi":"10.1051/matecconf/202337805001","DOIUrl":"https://doi.org/10.1051/matecconf/202337805001","url":null,"abstract":"Sensing coatings are rapidly entering the field of non-destructive tests. While cement-based composites are proving an excellent interaction with new/recent structures, polymer-based coatings, already employed for structural retrofitting purposes, can provide a valuable alternative. This study investigated the production, application, and use of poly(vinylidene fluoride) (PVDF) coatings. A 10w/v% PVDF-to-solvent ratio became the best trade-off between electrical conductivity and bond strength with the substrate. Different concentrations of Carbon Nanotubes (CNT) were investigated: 0.05, 0.10, 0.25, 0.50, and 0.75% by weight of PVDF. The conductive PVDF-CNT composites were brushed on the casted mortar beams with screws embedded as electrodes. The mortar beams and attached polymer coatings were then subjected to bending stress. The Gauge Factor was obtained by comparing the substrate’s strain with the coating’s electric response. The sensing intervals in the Fractional Change of Resistance-strain curves varied in relation to the CNT concentration. For instance, adding 0.50w/v% of CNT gave the highest sensitivity up to 0.2‰ strain, followed by a lower – still sufficient – gauge factor. PVDF-based coatings with CNT additions of 0.25 and 0.75w/v% witnessed a comparable sensing performance in the same strain limits, abruptly increasing and finally stabilizing to a low gauge factor. In contrast, both 0.05 and 0.10w/v% resulted in a low monitoring potential overall. The varying sensing zones experienced by the coating were attributed to the microscopical behavior of CNT within the PVDF matrix. In conclusion, the results highlighted the potentiality of polymeric coatings for sensing, monitoring, and inspection of concrete structures.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82627617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337802016
G. Anglani, J. Tulliani, P. Antonaci
The use of polymer precursors as repairing agents in capsule-based self-healing systems has been extensively studied in recent years. In particular, the effectiveness of macro-encapsulated polyurethane in restoring both watertightness and mechanical properties has been demonstrated at the laboratory level, and the experimental methods to test the effectiveness have been validated following pre-standard procedures. However, the use of macro-capsules containing polyurethane precursors for field applications has not been sufficiently implemented yet. For these systems to become appealing to the construction industry, it is essential to further characterize the self-healing effect in terms of stability in time, namely, to investigate the behavior of the self-healing system when subjected to recurring actions that can affect structures in time, after cracking and subsequent self-repairing. The goal of this study was to characterize the ability of commercial polyurethane foams to withstand cyclic flexural actions and repeated temperature variations after release from cementitious macro-capsules embedded in mortar specimens. The specimens were tested immediately after pre-cracking and self-repairing to characterize the initial sealing efficiency through a water-flow test. The same test was repeated at prescribed time intervals to analyze the evolution of the sealing efficiency with the applied mechanical and thermal stresses. The results showed that the proposed system has good stability against the selected damaging actions and confirmed the potential of encapsulated polyurethane for self-healing applications.
{"title":"Experimental investigation on the ability of macro-encapsulated polyurethane to resist cyclic damaging actions in self-repaired cement-based elements","authors":"G. Anglani, J. Tulliani, P. Antonaci","doi":"10.1051/matecconf/202337802016","DOIUrl":"https://doi.org/10.1051/matecconf/202337802016","url":null,"abstract":"The use of polymer precursors as repairing agents in capsule-based self-healing systems has been extensively studied in recent years. In particular, the effectiveness of macro-encapsulated polyurethane in restoring both watertightness and mechanical properties has been demonstrated at the laboratory level, and the experimental methods to test the effectiveness have been validated following pre-standard procedures. However, the use of macro-capsules containing polyurethane precursors for field applications has not been sufficiently implemented yet. For these systems to become appealing to the construction industry, it is essential to further characterize the self-healing effect in terms of stability in time, namely, to investigate the behavior of the self-healing system when subjected to recurring actions that can affect structures in time, after cracking and subsequent self-repairing. The goal of this study was to characterize the ability of commercial polyurethane foams to withstand cyclic flexural actions and repeated temperature variations after release from cementitious macro-capsules embedded in mortar specimens. The specimens were tested immediately after pre-cracking and self-repairing to characterize the initial sealing efficiency through a water-flow test. The same test was repeated at prescribed time intervals to analyze the evolution of the sealing efficiency with the applied mechanical and thermal stresses. The results showed that the proposed system has good stability against the selected damaging actions and confirmed the potential of encapsulated polyurethane for self-healing applications.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82593025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337802001
M. H. Khaneghahi, Divya Kamireddi, Seyed Ali Rahmaninezhad, C. Schauer, Christopher M. Sales, A. Najafi, Aidan Cotton, Amir Sadighi, Y. Farnam
The goal of this research is to develop innovative damage-responsive bacterial-based self-healing fibers (hereafter called BioFiber) that can be incorporated into concrete to enable two functionalities simultaneously: (1) crack bridging functionality to control crack growth and (2) crack healing functionality when a crack occurs. The BioFiber is comprised of a load-bearing core fiber, a sheath of bacteria-laden hydrogel, and an outer impermeable strain-responsive shell coating. An instant soaking manufacturing process was used with multiple reservoirs containing bacteria-laden, hydrophilic prepolymer and crosslinking reagents to develop BioFiber. Sodium-alginate was used as a prepolymer to produce calcium-alginate hydrogel via ionic crosslinking on the core fiber. The dormant bacteria (spore) of Lysinibacillus sphaericus was incorporated in hydrogel as a self-healing agent. Then, an impermeable polymeric coating was applied to the hydrogel-coated core fibers. The impermeable strain-responsive shell coating material was manufactured using the polymer blend of polystyrene and polylactic acid. The high swelling capacity of calcium-alginate provides the water required for the microbially induced calcium carbonate precipitation (MICP) chemical pathway, i.e., ureolysis in this study. The strain-responsive impermeable coating provides adequate flexibility during concrete casting to protect the spores and alginate before cracking and sufficient stress-strain behavior to grant damage-responsiveness upon crack occurrence to activate MICP. To evaluate the behavior of developed BioFiber, the swelling capacity of the hydrogel, the impermeability of shell coating, the spore casting survivability, and MICP activities were investigated.
{"title":"Development of bio-inspired multi-functional polymeric-based fibers (BioFiber) for advanced delivery of bacterial-based self-healing agent in concrete","authors":"M. H. Khaneghahi, Divya Kamireddi, Seyed Ali Rahmaninezhad, C. Schauer, Christopher M. Sales, A. Najafi, Aidan Cotton, Amir Sadighi, Y. Farnam","doi":"10.1051/matecconf/202337802001","DOIUrl":"https://doi.org/10.1051/matecconf/202337802001","url":null,"abstract":"The goal of this research is to develop innovative damage-responsive bacterial-based self-healing fibers (hereafter called BioFiber) that can be incorporated into concrete to enable two functionalities simultaneously: (1) crack bridging functionality to control crack growth and (2) crack healing functionality when a crack occurs. The BioFiber is comprised of a load-bearing core fiber, a sheath of bacteria-laden hydrogel, and an outer impermeable strain-responsive shell coating. An instant soaking manufacturing process was used with multiple reservoirs containing bacteria-laden, hydrophilic prepolymer and crosslinking reagents to develop BioFiber. Sodium-alginate was used as a prepolymer to produce calcium-alginate hydrogel via ionic crosslinking on the core fiber. The dormant bacteria (spore) of Lysinibacillus sphaericus was incorporated in hydrogel as a self-healing agent. Then, an impermeable polymeric coating was applied to the hydrogel-coated core fibers. The impermeable strain-responsive shell coating material was manufactured using the polymer blend of polystyrene and polylactic acid. The high swelling capacity of calcium-alginate provides the water required for the microbially induced calcium carbonate precipitation (MICP) chemical pathway, i.e., ureolysis in this study. The strain-responsive impermeable coating provides adequate flexibility during concrete casting to protect the spores and alginate before cracking and sufficient stress-strain behavior to grant damage-responsiveness upon crack occurrence to activate MICP. To evaluate the behavior of developed BioFiber, the swelling capacity of the hydrogel, the impermeability of shell coating, the spore casting survivability, and MICP activities were investigated.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86920352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202338201041
Peixian Bai, Yixuan Jia
Under different types of internal and external faults of transformers, electrical quantities such as voltage, differential current and transformer oil flow rate change accordingly. In this paper, the variation law is studied, and the variation law of differential current and other electrical quantities under different types of faults and abnormal conditions inside and outside the transformer area is verified by simulation. The characteristics of faults inside and outside the area are different, and the faults inside and outside the transformer area are judged. At the same time, ANSYS Maxwell 3D, ANSYS Fluent and other software are used to model and simulate the transformer, and the oil flow rate changes under different operating conditions such as normal operation, external fault and internal fault of the transformer are analyzed.
{"title":"Simulation analysis of internal and external faults in transformer area","authors":"Peixian Bai, Yixuan Jia","doi":"10.1051/matecconf/202338201041","DOIUrl":"https://doi.org/10.1051/matecconf/202338201041","url":null,"abstract":"Under different types of internal and external faults of transformers, electrical quantities such as voltage, differential current and transformer oil flow rate change accordingly. In this paper, the variation law is studied, and the variation law of differential current and other electrical quantities under different types of faults and abnormal conditions inside and outside the transformer area is verified by simulation. The characteristics of faults inside and outside the area are different, and the faults inside and outside the transformer area are judged. At the same time, ANSYS Maxwell 3D, ANSYS Fluent and other software are used to model and simulate the transformer, and the oil flow rate changes under different operating conditions such as normal operation, external fault and internal fault of the transformer are analyzed.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87028006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337805003
Ana Martínez-Ibernón, P. Antonaci, G. Anglani
The sustainable development of societies can be pursued by simultaneously avoiding the depletion of materials and resources and reducing the greenhouse gases emissions, with related climatic change effects. In order to get this, the extension of structures service-life plays a significant role in saving natural resources, decreasing the overall anthropogenic carbon-footprint, and reducing building and demolition wastes. In order to achieve such prolongation of structures service-life, one of the most promising approaches is the development of Smart Structures. These are defined as structures that are able to self-sense some external stimuli such as stress or temperature variations, and internal conditions such as chloride penetration, concrete carbonatation, etc. Consequently, ongoing damage phenomena can be detected promptly, thus allowing to implement suitable countermeasures in the most efficient way. Smart Structures can also process the information and respond autonomously in real time by using smart materials technologies such as self-healing technology. In this study we propose a preliminary version of a smart material system with self-healing and sensing properties, to demonstrate its effectiveness at a proof of concept level. The effectiveness of an active, capsule-based self-healing system in blocking chloride penetration through the crack and the effectiveness of voltametric Ag sensors in detecting the presence of chlorides were investigated experimentally. High-performance cement mortar was chosen as the material to be studied, in order to ensure that optimal behaviour could be observed in non-cracked conditions.
{"title":"Initial proposal of a smart cement-based material to enhance the service-life of reinforcement concrete structures","authors":"Ana Martínez-Ibernón, P. Antonaci, G. Anglani","doi":"10.1051/matecconf/202337805003","DOIUrl":"https://doi.org/10.1051/matecconf/202337805003","url":null,"abstract":"The sustainable development of societies can be pursued by simultaneously avoiding the depletion of materials and resources and reducing the greenhouse gases emissions, with related climatic change effects. In order to get this, the extension of structures service-life plays a significant role in saving natural resources, decreasing the overall anthropogenic carbon-footprint, and reducing building and demolition wastes. In order to achieve such prolongation of structures service-life, one of the most promising approaches is the development of Smart Structures. These are defined as structures that are able to self-sense some external stimuli such as stress or temperature variations, and internal conditions such as chloride penetration, concrete carbonatation, etc. Consequently, ongoing damage phenomena can be detected promptly, thus allowing to implement suitable countermeasures in the most efficient way. Smart Structures can also process the information and respond autonomously in real time by using smart materials technologies such as self-healing technology. In this study we propose a preliminary version of a smart material system with self-healing and sensing properties, to demonstrate its effectiveness at a proof of concept level. The effectiveness of an active, capsule-based self-healing system in blocking chloride penetration through the crack and the effectiveness of voltametric Ag sensors in detecting the presence of chlorides were investigated experimentally. High-performance cement mortar was chosen as the material to be studied, in order to ensure that optimal behaviour could be observed in non-cracked conditions.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90110221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202337809004
S. Sayadi, E. Ricketts, E. Schlangen, P. Cleall, I. Mihai, A. Jefferson
Self-healing cementitious materials with microcapsules are complex multiscale and multiphase materials. The random microstructure of these materials governs their mechanical and transport behaviour. The actual microstructure can be represented accurately with a discrete lattice model, but computational restrictions mean that the size of domain that can be considered with this approach is limited. By contrast, a smeared approach, based on a micromechanical formulation, provides an approximate representation of the material microstructure with low computational costs. The aim of this paper is to compare simulations of a microcapsule-based self-healing cementitious system with discrete-lattice and smeared-micromechanical models, and to assess the relative strengths and weaknesses of these models for simulating distributed fracture and healing in this type of self-healing material. A novel random field generation technique is used to represent the microstructure of a cementitious mortar specimen. The meshes and elements are created by the triangulation method and used to determine the input required for the lattice model. The paper also describes the enhancement of the TUDelft lattice model to include self-healing behaviour. The extended micromechanical model considers both microcracking and healing. The findings from the study provide insight into the relative merits of these two modelling approaches.
{"title":"Effect of microstructure heterogeneity shapes on constitutive behaviour of encapsulated self-healing cementitious materials","authors":"S. Sayadi, E. Ricketts, E. Schlangen, P. Cleall, I. Mihai, A. Jefferson","doi":"10.1051/matecconf/202337809004","DOIUrl":"https://doi.org/10.1051/matecconf/202337809004","url":null,"abstract":"Self-healing cementitious materials with microcapsules are complex multiscale and multiphase materials. The random microstructure of these materials governs their mechanical and transport behaviour. The actual microstructure can be represented accurately with a discrete lattice model, but computational restrictions mean that the size of domain that can be considered with this approach is limited. By contrast, a smeared approach, based on a micromechanical formulation, provides an approximate representation of the material microstructure with low computational costs. The aim of this paper is to compare simulations of a microcapsule-based self-healing cementitious system with discrete-lattice and smeared-micromechanical models, and to assess the relative strengths and weaknesses of these models for simulating distributed fracture and healing in this type of self-healing material. A novel random field generation technique is used to represent the microstructure of a cementitious mortar specimen. The meshes and elements are created by the triangulation method and used to determine the input required for the lattice model. The paper also describes the enhancement of the TUDelft lattice model to include self-healing behaviour. The extended micromechanical model considers both microcracking and healing. The findings from the study provide insight into the relative merits of these two modelling approaches.","PeriodicalId":18309,"journal":{"name":"MATEC Web of Conferences","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90164108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1051/matecconf/202338201023
Chang Cao, Xingxing Feng, Min Liu
Many constitutive models’ finite element (FE) models and lumped parameter models included have been presented for rubber bushings. In general, the FE models cannot be directly used in mechanical multibody systems with bushings, and the lumped parameter models can not consider the coupled modes of deformation of bushings. For this reason, a two-dimensional lumped parameter model for rubber bushings is presented, which considers the coupled radial-torsional deformation and can be easily implemented into mechanical multibody systems. FE method is used to simulate the rubber bushing subjected to a coupled radial-torsional deformation. A procedure to determine the model parameters is presented. The proposed coupled bushing model and a traditional one-dimensional bushing model are applied into a simple multibody system and compared. Simulation results show the coupled radial-torsional behavior of the bushing.
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