G. Anglani, P. Antonaci, Susana I. Carillo Gonzales, Giorgia Paganelli, J. Tulliani
{"title":"3D printed capsules for self-healing concrete applications","authors":"G. Anglani, P. Antonaci, Susana I. Carillo Gonzales, Giorgia Paganelli, J. Tulliani","doi":"10.21012/FC10.235356","DOIUrl":"https://doi.org/10.21012/FC10.235356","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"70 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133007093","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}
{"title":"Ductile-to-brittle transition in fiber-reinforced brittle-matrix composites: Scale and fiber volume fraction effects","authors":"A. Carpinteri","doi":"10.21012/FC10.234076","DOIUrl":"https://doi.org/10.21012/FC10.234076","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124208749","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}
A modelling approach is proposed to simulate drying shrinkage and shrinkageinduced microcracking in cement paste. The proposed approach takes into consideration the heterogeneous nature of the cement paste as well as the development of the microstructure due to fast-paced hydration at early-ages. Simulations show that the development of microcracking depends on the initial conditions, the drying depth and the drying threshold age.
{"title":"Numerical simulation of microcracking induced by drying shrinkage in early age cement pastes","authors":"A. Rhardane","doi":"10.21012/FC10.235657","DOIUrl":"https://doi.org/10.21012/FC10.235657","url":null,"abstract":"A modelling approach is proposed to simulate drying shrinkage and shrinkageinduced microcracking in cement paste. The proposed approach takes into consideration the heterogeneous nature of the cement paste as well as the development of the microstructure due to fast-paced hydration at early-ages. Simulations show that the development of microcracking depends on the initial conditions, the drying depth and the drying threshold age.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124402611","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}
Traditionally, mechanical properties of cementitious materials are designed “chemically”, namely by configuring their mix proportions. Owning to the development of 3D printing technology, “physical” tailoring the meso-structure of cementitious materials to design their mechanical properties becomes possible. In the present study, cementitious materials were designed both by configuring the meso-structure and the base material mix proportions. Circle and ellipse cellular structure were designed and molds for casting were prepared by 3D printing technique. Plain mortar (REF) and polyvinyl alcohol (PVA) fiber reinforced mortar (FRM) were used as base material. After casting, curing and demolding, uniaxial compression tests were performed on these cementitious cellular composites. The cellular composites exhibit three stages of compressive fracture behavior, including fracture and deformation of the cellular structure, crushing of the base material and compacting of crushed materials. With ellipse cellular design, negative Poisson’s ratio was achieved during the compression and the overall energy absorption efficiency and deformability was higher than circular design cellular which implies that this cementitious cellular material be a promising impact resistant material.
{"title":"Compression behaviors of cementitious cellular composites with negative Poisson's ratio","authors":"Yading Xu, B. Šavija, E. Schlangen","doi":"10.21012/FC10.234801","DOIUrl":"https://doi.org/10.21012/FC10.234801","url":null,"abstract":"Traditionally, mechanical properties of cementitious materials are designed “chemically”, namely by configuring their mix proportions. Owning to the development of 3D printing technology, “physical” tailoring the meso-structure of cementitious materials to design their mechanical properties becomes possible. In the present study, cementitious materials were designed both by configuring the meso-structure and the base material mix proportions. Circle and ellipse cellular structure were designed and molds for casting were prepared by 3D printing technique. Plain mortar (REF) and polyvinyl alcohol (PVA) fiber reinforced mortar (FRM) were used as base material. After casting, curing and demolding, uniaxial compression tests were performed on these cementitious cellular composites. The cellular composites exhibit three stages of compressive fracture behavior, including fracture and deformation of the cellular structure, crushing of the base material and compacting of crushed materials. With ellipse cellular design, negative Poisson’s ratio was achieved during the compression and the overall energy absorption efficiency and deformability was higher than circular design cellular which implies that this cementitious cellular material be a promising impact resistant material.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121446939","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}
As a detailed inspection of a concrete structure in service, core samples are usually drilled out and then physical properties are measured. In this study, damage estimation of structural concrete from concrete-core samples is developed, applying acoustic emission (AE) and X-ray CT methods. By the authors, the quantitative damage evaluation of concrete has been proposed in RILEM TC-212ACD, by applying AE energy parameter and damage mechanics in the compression test. In this study, detection of cracking damage in concrete by detected AE energy in core test. Prior to the compression test, distribution of micro-cracks in a concrete-core sample is inspected by helical X-ray computer tomography (CT). Then, freeze-thawed samples are tested by the compression test with AE measurement. Concrete-core samples were taken out of a head works in Hokkaido, Japan which is extremely developed inner damage. Thus, it is demonstrated that the concentration of material damage could be evaluated by comparing geometrical characteristics of cracks with the “energy rate” of AE generation, which is analyzed by AE parameter analysis. A relation between AE energy rate and damage parameters is correlated, and thus the damage of concrete is qualitatively estimated.
{"title":"Development of damage parameter for concrete by using acoustic emission and X ray computed tomography","authors":"S. Tetsuya","doi":"10.21012/FC10.235413","DOIUrl":"https://doi.org/10.21012/FC10.235413","url":null,"abstract":"As a detailed inspection of a concrete structure in service, core samples are usually drilled out and then physical properties are measured. In this study, damage estimation of structural concrete from concrete-core samples is developed, applying acoustic emission (AE) and X-ray CT methods. By the authors, the quantitative damage evaluation of concrete has been proposed in RILEM TC-212ACD, by applying AE energy parameter and damage mechanics in the compression test. In this study, detection of cracking damage in concrete by detected AE energy in core test. Prior to the compression test, distribution of micro-cracks in a concrete-core sample is inspected by helical X-ray computer tomography (CT). Then, freeze-thawed samples are tested by the compression test with AE measurement. Concrete-core samples were taken out of a head works in Hokkaido, Japan which is extremely developed inner damage. Thus, it is demonstrated that the concentration of material damage could be evaluated by comparing geometrical characteristics of cracks with the “energy rate” of AE generation, which is analyzed by AE parameter analysis. A relation between AE energy rate and damage parameters is correlated, and thus the damage of concrete is qualitatively estimated.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127595501","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}
{"title":"Coupling statistical indentation and microscopy to evaluate micromechanical properties of cementitious materials","authors":"B. Hilloulin","doi":"10.21012/FC10.233613","DOIUrl":"https://doi.org/10.21012/FC10.233613","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125870143","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}
Frequency of loading plays a signicant role in influencing the fatigue response of concrete. It is widely accepted in the literature that concrete fatigue life increases with increase in loading frequency. This behaviour is counter-intuitive, as the specimen is expected to fail in less number of cycles when subjected to higher loading frequency. This paper aims at understanding the fracture and failure mechanisms responsible for this counter intuitive behaviour through an experimental investigation. The flexural fatigue experiments are performed on concrete beam specimens subjected to three different loading frequencies: 0.5 Hz, 2 Hz and 4 Hz with the aid of acoustic emission technique. The mechanical and acoustic emission results reveal that the increased fatigue life for specimens subjected to higher loading frequencies is attributed to the widely distributed and randomly oriented micro cracks that can blunt the effect of high stresses by increasing the energy required to cause failure. The concrete specimens subjected to lower loading frequencies tend to exhibit brittle behaviour and consequently fail at lower number of fatigue load cycles.
{"title":"Effect of Loading Frequency on Flexural Fatigue Behaviour of Concrete","authors":"K. Keerthana","doi":"10.21012/FC10.233285","DOIUrl":"https://doi.org/10.21012/FC10.233285","url":null,"abstract":"Frequency of loading plays a signicant role in influencing the fatigue response of concrete. It is widely accepted in the literature that concrete fatigue life increases with increase in loading frequency. This behaviour is counter-intuitive, as the specimen is expected to fail in less number of cycles when subjected to higher loading frequency. This paper aims at understanding the fracture and failure mechanisms responsible for this counter intuitive behaviour through an experimental investigation. The flexural fatigue experiments are performed on concrete beam specimens subjected to three different loading frequencies: 0.5 Hz, 2 Hz and 4 Hz with the aid of acoustic emission technique. The mechanical and acoustic emission results reveal that the increased fatigue life for specimens subjected to higher loading frequencies is attributed to the widely distributed and randomly oriented micro cracks that can blunt the effect of high stresses by increasing the energy required to cause failure. The concrete specimens subjected to lower loading frequencies tend to exhibit brittle behaviour and consequently fail at lower number of fatigue load cycles.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123424270","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}
{"title":"Support vector machine procedure and Gaussian mixture modelling of acoustic emission signals to study crack classification in reinforced concrete structures","authors":"R. Sagar","doi":"10.21012/FC10.235431","DOIUrl":"https://doi.org/10.21012/FC10.235431","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123721670","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}
{"title":"Modelling the stochastic tensile behavior and multiple cracking of strain-hardening cementitious composites (SHCCs)","authors":"J. Li","doi":"10.21012/FC10.233287","DOIUrl":"https://doi.org/10.21012/FC10.233287","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121691873","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}
C. Rodriguez, S. Figueiredo, F. F. D. M. Filho, E. Schlangen, B. Šavija
The potential of using phase change materials (PCM) in cementitious materials to mitigate damage due to thermal loadings has been recently focus of intensive research. In the case of PCM with transition temperatures near to the freezing point of water, their potential to delay frost in a cementitious matrix has been largely investigated through the monitoring of internal temperature changes when exposed to repeated cycles of subzero and ambient temperature. Yet, the effect of these admixtures to prevent damage in cement-based materials has not been directly studied. In this paper,mortars cylinders of two different sizes and containing 0, 10 and 30%of PCM replacement by volume of aggregates were subjected to frost salt scaling during freeze and thaw cycles. Prior to the start of the weathering and after cycles 1, 3, 7 and 15 the cylindrical specimens were subjected to X-ray microtomography to monitor morphological changes due to frost action, such as chipping and cracks. Compressive and flexural strength, coefficient of thermal expansion and apparent porosity of the undamaged composites were also investigated. Results suggest that the improvement of frost scaling resistance of the mortars with incorporated PCM is a trade-off between resulting mechanical proper-ties, thermal volume stability and porosity of the composite, as evinced from the better performance of mortars with 10%of PCM replacement.
{"title":"Frost damage progression studied through X-Ray tomography in mortar with Phase Change Materials","authors":"C. Rodriguez, S. Figueiredo, F. F. D. M. Filho, E. Schlangen, B. Šavija","doi":"10.21012/FC10.235085","DOIUrl":"https://doi.org/10.21012/FC10.235085","url":null,"abstract":"The potential of using phase change materials (PCM) in cementitious materials to mitigate damage due to thermal loadings has been recently focus of intensive research. In the case of PCM with transition temperatures near to the freezing point of water, their potential to delay frost in a cementitious matrix has been largely investigated through the monitoring of internal temperature changes when exposed to repeated cycles of subzero and ambient temperature. Yet, the effect of these admixtures to prevent damage in cement-based materials has not been directly studied. In this paper,mortars cylinders of two different sizes and containing 0, 10 and 30%of PCM replacement by volume of aggregates were subjected to frost salt scaling during freeze and thaw cycles. Prior to the start of the weathering and after cycles 1, 3, 7 and 15 the cylindrical specimens were subjected to X-ray microtomography to monitor morphological changes due to frost action, such as chipping and cracks. Compressive and flexural strength, coefficient of thermal expansion and apparent porosity of the undamaged composites were also investigated. Results suggest that the improvement of frost scaling resistance of the mortars with incorporated PCM is a trade-off between resulting mechanical proper-ties, thermal volume stability and porosity of the composite, as evinced from the better performance of mortars with 10%of PCM replacement.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122067207","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}
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