{"title":"A neural network ensemble for the identification of mechanical fracture parameters of Fine-grained Brittle Matrix Composites","authors":"D. Lehký","doi":"10.21012/FC10.234717","DOIUrl":"https://doi.org/10.21012/FC10.234717","url":null,"abstract":"","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":"123721989","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}
Performance of anchorage reinforcement under dynamic loads is important to ensure adequate safety and structural integrity with adequate ductility. In the end regions, load transfer mechanism is influenced by cyclic loads under overloads. Since anchorage bond and its mechanics under cyclic over loading are absent, an experimental study to investigate the influence of type of loading and lateral confinement have been performed. Anchorage bond in concrete with different lateral confinement by spiral reinforcement has been studied under cyclic loading. The bond length was 80mm in the middle of 150mm depth of concrete. Bar diameter of 25mm was embedded in 25 MPa strength concrete with spirals of 8mm diameter with pitch of 25mm, 50mm and 75mm was adopted. It has been observed that the strength of concrete and the level of lateral confinement showed significant influence on the mode of failure and bond stress. Pullout failure was observed under monotonic and cyclic loading under overload in confined concrete. Different failure modes have been observed depending on the influencing parameters. The life of reinforced concrete due to deterioration of anchorage bond in rebars under cyclic loading is significantly reduced by the accidental overloads. The early application of overloads lowers the bond strength and service life of reinforced concrete. Abhishek, P, Harekrishna Kumar, and G. Appa Rao
{"title":"Cyclic over loads on life of bond anchorages in reinforced concrete","authors":"P. Abhishek","doi":"10.21012/FC10.235422","DOIUrl":"https://doi.org/10.21012/FC10.235422","url":null,"abstract":"Performance of anchorage reinforcement under dynamic loads is important to ensure adequate safety and structural integrity with adequate ductility. In the end regions, load transfer mechanism is influenced by cyclic loads under overloads. Since anchorage bond and its mechanics under cyclic over loading are absent, an experimental study to investigate the influence of type of loading and lateral confinement have been performed. Anchorage bond in concrete with different lateral confinement by spiral reinforcement has been studied under cyclic loading. The bond length was 80mm in the middle of 150mm depth of concrete. Bar diameter of 25mm was embedded in 25 MPa strength concrete with spirals of 8mm diameter with pitch of 25mm, 50mm and 75mm was adopted. It has been observed that the strength of concrete and the level of lateral confinement showed significant influence on the mode of failure and bond stress. Pullout failure was observed under monotonic and cyclic loading under overload in confined concrete. Different failure modes have been observed depending on the influencing parameters. The life of reinforced concrete due to deterioration of anchorage bond in rebars under cyclic loading is significantly reduced by the accidental overloads. The early application of overloads lowers the bond strength and service life of reinforced concrete. Abhishek, P, Harekrishna Kumar, and G. Appa Rao","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":"121668890","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":"Investigations of size effect in concrete during splitting using DEM combined with X-Ray Micro-CT scans","authors":"J. Suchorzewski","doi":"10.21012/FC10.233583","DOIUrl":"https://doi.org/10.21012/FC10.233583","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"108 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":"124153491","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}
This study presents experimental investigations on the shear carrying capacity of RC beams in which alkaline silica reaction (ASR) of the concrete has occurred. In the experiments, RC beams with shear span effective depth ratio, a/d = 1.0, 2.5 and 4.5 were prepared. Before conducting a loading test, visual observation and measurements of the crack and crack width were conducted using a digital microscope to quantitatively evaluate the degree of damage caused by the cracks due to the ASR. In the shear loading test, the initiation and propagation of the diagonal cracks were measured by image analysis, and simultaneously rebar strain and concrete strain were measured to calculate the neutral axis in the beam section. The experiments show that the effects of a/d ratio on the shear strength of the RC beams with different durations of outdoor exposure can be clarified based on the difference in the angle and propagation of the diagonal cracks.
{"title":"Shear carrying capacity of reinforced concrete beams with various a/d ratios damaged due to the Alkali-Silica reaction","authors":"T. Miki","doi":"10.21012/FC10.235490","DOIUrl":"https://doi.org/10.21012/FC10.235490","url":null,"abstract":"This study presents experimental investigations on the shear carrying capacity of RC beams in which alkaline silica reaction (ASR) of the concrete has occurred. In the experiments, RC beams with shear span effective depth ratio, a/d = 1.0, 2.5 and 4.5 were prepared. Before conducting a loading test, visual observation and measurements of the crack and crack width were conducted using a digital microscope to quantitatively evaluate the degree of damage caused by the cracks due to the ASR. In the shear loading test, the initiation and propagation of the diagonal cracks were measured by image analysis, and simultaneously rebar strain and concrete strain were measured to calculate the neutral axis in the beam section. The experiments show that the effects of a/d ratio on the shear strength of the RC beams with different durations of outdoor exposure can be clarified based on the difference in the angle and propagation of the diagonal cracks.","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":"126500097","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":"Fishnet Statistics for Design of Quasibrittle and Biomimetic Materials and Structures for Failure Probability <10-6","authors":"Z. Bažant","doi":"10.21012/FC10.237725","DOIUrl":"https://doi.org/10.21012/FC10.237725","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"44 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":"125808449","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}
This paper presents the coupled hydro-mechanical simulation tool, TOUGH-RBSN, to investigate fundamental aspects of hydraulic fracture of cement-based composites. The TOUGHRBSN simulator is based on the effective linking of two numerical methods: TOUGH2, a finite volume method for simulating mass transport within a permeable medium; and a lattice model based on the rigid-body-spring network (RBSN) concept. The material is represented as a threephase composite consisting of a mortar matrix, coarse aggregate inclusions, and matrix–inclusion interfaces. Local fracture permeabilities and porosities are based on the crack apertures computed by the mechanical model. The simulator is used to study the effects of weak interfaces on the hydraulic fracturing processes.
{"title":"Simulating Hydraulic Fracturing Processes in Cement Composites using TOUGH-RBSN","authors":"D. Asahina","doi":"10.21012/FC10.234645","DOIUrl":"https://doi.org/10.21012/FC10.234645","url":null,"abstract":"This paper presents the coupled hydro-mechanical simulation tool, TOUGH-RBSN, to investigate fundamental aspects of hydraulic fracture of cement-based composites. The TOUGHRBSN simulator is based on the effective linking of two numerical methods: TOUGH2, a finite volume method for simulating mass transport within a permeable medium; and a lattice model based on the rigid-body-spring network (RBSN) concept. The material is represented as a threephase composite consisting of a mortar matrix, coarse aggregate inclusions, and matrix–inclusion interfaces. Local fracture permeabilities and porosities are based on the crack apertures computed by the mechanical model. The simulator is used to study the effects of weak interfaces on the hydraulic fracturing processes.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"35 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":"126065731","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":"Effect of Interfacial Transition Zone on Fracture Energy in Concrete","authors":"D. Samal","doi":"10.21012/FC10.235522","DOIUrl":"https://doi.org/10.21012/FC10.235522","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"1 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":"129349811","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}
This paper presents an enhanced theoretical formulation and associated computational framework for brittle fracture in nuclear graphite within the context of configurational mechanics. A new condition for crack front equilibrium is exploited that leads to an implicit crack propagation formulation. This paper focuses on an extension of our previous work, whereby the complex internal stress state in a nuclear reactor is the primary driver for crack propagation in individual graphite bricks. The resulting crack path is resolved as a discrete displacement discontinuity, where the material displacements of the nodes on the crack front change continuously, without the need for enrichment techniques. Performance of the formulation is demonstrated by means of a representative numerical simulation, demonstrating both accuracy and robustness.
{"title":"Fracture propagation in nuclear graphite","authors":"L. Kaczmarczyk","doi":"10.21012/FC10.235469","DOIUrl":"https://doi.org/10.21012/FC10.235469","url":null,"abstract":"This paper presents an enhanced theoretical formulation and associated computational framework for brittle fracture in nuclear graphite within the context of configurational mechanics. A new condition for crack front equilibrium is exploited that leads to an implicit crack propagation formulation. This paper focuses on an extension of our previous work, whereby the complex internal stress state in a nuclear reactor is the primary driver for crack propagation in individual graphite bricks. The resulting crack path is resolved as a discrete displacement discontinuity, where the material displacements of the nodes on the crack front change continuously, without the need for enrichment techniques. Performance of the formulation is demonstrated by means of a representative numerical simulation, demonstrating both accuracy and robustness.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"19 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":"128017243","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":"Mechanical evaluation of 3D printable nano-silica incorporated fibre-reinforced lightweight foam concrete","authors":"S. Cho","doi":"10.21012/FC10.232696","DOIUrl":"https://doi.org/10.21012/FC10.232696","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"52 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":"124499837","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":"DEM investigations of effect of Interfacial transition zones on concrete fracture","authors":"M. Nitka","doi":"10.21012/FC10.233601","DOIUrl":"https://doi.org/10.21012/FC10.233601","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"1 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":"129922373","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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