{"title":"Mesoscale numerical study of aggregate size in concrete by discrete element method","authors":"R. Zhu","doi":"10.21012/FC10.235426","DOIUrl":"https://doi.org/10.21012/FC10.235426","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"58 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":"122912990","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 Fibers, Distributed Net Reinforcement and Sharp Corners on Fracture and Size Effect in Concrete Structures","authors":"Z. Bažant","doi":"10.21012/FC10.237978","DOIUrl":"https://doi.org/10.21012/FC10.237978","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"42 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":"126975945","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}
It is known that the fatigue resistance of concrete decreases when it becomes saturated with water, and that its compressive strength increases at low temperature. However, there have been few systematic investigations of the influence of the environmental temperature and moisture conditions on the fatigue resistance of concrete. In the present study, static loading and fatigue tests were carried out on concrete cylinders to determine their fatigue resistance under compression. The results indicated that at room temperature, the static compressive strength decreased with increasing moisture content. In contrast, at low temperature, it increased with increasing moisture content. On the other hand, regardless of the temperature, the fatigue resistance decreased as the moisture content increased.
{"title":"Experimental study of ambient temperature and moisture conditions on fatigue resistance of concrete","authors":"Y. Koda","doi":"10.21012/FC10.235057","DOIUrl":"https://doi.org/10.21012/FC10.235057","url":null,"abstract":"It is known that the fatigue resistance of concrete decreases when it becomes saturated with water, and that its compressive strength increases at low temperature. However, there have been few systematic investigations of the influence of the environmental temperature and moisture conditions on the fatigue resistance of concrete. In the present study, static loading and fatigue tests were carried out on concrete cylinders to determine their fatigue resistance under compression. The results indicated that at room temperature, the static compressive strength decreased with increasing moisture content. In contrast, at low temperature, it increased with increasing moisture content. On the other hand, regardless of the temperature, the fatigue resistance decreased as the moisture content increased.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"66 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":"133790831","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 discusses on some experimental investigations on performance of concrete incorporated with fly ash as cement replacement material. The fly ash content was varied from 0.0% to 60.0% by weight of cement. Different concrete mixes were proportioned at constant binder content with different water-binder ratios. The influence of these parameters on the ability of concrete to withstand the impact of aggressive H2SO4 concentration in water solution. Three different concentrations of 1.0, 3.0 and 5.0% of H2SO4 in solution have been adopted to investigate the loss in strength and weight of concrete. Concrete immersed in concentrated H2SO4 solution showed significant deterioration and color change. The strength of concrete decreases with increase in H2SO4 concentration. As the concentration of H2SO4 increases the loss of weight of concrete increases. At low replacements of cement by fly ash, the losses in strength and weight have been observed to be significantly high. As the percentage of fly ash in cement increases, there has been significant improvement in the resistance of concrete against H2SO4 influence. The losses in strength and weight of concrete decrease high volume fly ash concrete mixes. With different combinations of cementitious material (cement plus fly ash = binder), water-binder ratio and concentration of H2SO4, the concretes produced using high volume fly ash improve their durability. High volume fly ash concrete seems to be an efficient material for developing high performing durable concretes.
{"title":"Durability of high volume fly ash concrete exposed to H2SO4 environment","authors":"M. Rao","doi":"10.21012/FC10.235415","DOIUrl":"https://doi.org/10.21012/FC10.235415","url":null,"abstract":"This paper discusses on some experimental investigations on performance of concrete incorporated with fly ash as cement replacement material. The fly ash content was varied from 0.0% to 60.0% by weight of cement. Different concrete mixes were proportioned at constant binder content with different water-binder ratios. The influence of these parameters on the ability of concrete to withstand the impact of aggressive H2SO4 concentration in water solution. Three different concentrations of 1.0, 3.0 and 5.0% of H2SO4 in solution have been adopted to investigate the loss in strength and weight of concrete. Concrete immersed in concentrated H2SO4 solution showed significant deterioration and color change. The strength of concrete decreases with increase in H2SO4 concentration. As the concentration of H2SO4 increases the loss of weight of concrete increases. At low replacements of cement by fly ash, the losses in strength and weight have been observed to be significantly high. As the percentage of fly ash in cement increases, there has been significant improvement in the resistance of concrete against H2SO4 influence. The losses in strength and weight of concrete decrease high volume fly ash concrete mixes. With different combinations of cementitious material (cement plus fly ash = binder), water-binder ratio and concentration of H2SO4, the concretes produced using high volume fly ash improve their durability. High volume fly ash concrete seems to be an efficient material for developing high performing durable concretes.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"32 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114037094","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}
The performance of a bi-material interface is one of the major concerns in the repair or strengthening of concrete structural elements. In this study, a novel testing method for interface shear fractures of plain concrete and fiber-reinforced cementitious composites is proposed to avoid tensile failure during the test. Double-edge notched and unnotched specimens are utilized. Analytical, numerical, and experimental investigations are carried out to validate this method. The stress intensity factor K of the double-edge specimen with bi-materials is analytically obtained by the J-integral method. Based on ultra-high toughness cementitious composite (UHTCC)/concrete models, a numerical investigation of the proposed method is performed to confirm its suitability for shear fracture tests. Furthermore, the double-edge UHTCC/concrete specimens are experimentally investigated. The proposed method can be applied to obtain the interface shear parameters of concrete materials, which are needed for analytical or numerical analyses of bi-material interfaces in concrete structures.
{"title":"Testing method for interface mode II fracture of plain concrete and fiber-reinforced cementitious composite","authors":"Bo-Tao Huang","doi":"10.21012/FC10.233093","DOIUrl":"https://doi.org/10.21012/FC10.233093","url":null,"abstract":"The performance of a bi-material interface is one of the major concerns in the repair or strengthening of concrete structural elements. In this study, a novel testing method for interface shear fractures of plain concrete and fiber-reinforced cementitious composites is proposed to avoid tensile failure during the test. Double-edge notched and unnotched specimens are utilized. Analytical, numerical, and experimental investigations are carried out to validate this method. The stress intensity factor K of the double-edge specimen with bi-materials is analytically obtained by the J-integral method. Based on ultra-high toughness cementitious composite (UHTCC)/concrete models, a numerical investigation of the proposed method is performed to confirm its suitability for shear fracture tests. Furthermore, the double-edge UHTCC/concrete specimens are experimentally investigated. The proposed method can be applied to obtain the interface shear parameters of concrete materials, which are needed for analytical or numerical analyses of bi-material interfaces in concrete structures.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"127 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":"114310980","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":"Cracking at early age of a massive reinforced concrete structure : case of the gusset of the VeRCoRs mock-up","authors":"J. Mazars","doi":"10.21012/FC10.234286","DOIUrl":"https://doi.org/10.21012/FC10.234286","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"6 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":"114390051","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}
Following recent earthquakes in Japan, there are several reports of damage to nonstructural walls in reinforced concrete buildings, which causes problems for their continued use. Thus, it is important to consider structural strength as well as damages in design. In this paper, we propose a performance design method to evaluate the fracture mechanism of non-structural walls. In other words, we propose a method to evaluate the levels of shear crack (i.e., width, number of cracks, and crack width) to determine the relationship between shear load and deformation. We focus specifically on crack width. First, we conducted an experiment on the walls and investigated the influence of the rebar arrangement on cracks. The shear strength increases, and the crack width was found to decrease when the rebar separation became narrower and the rebar ratio increased. Subsequently, we reproduced the behaviors of the test specimens observed in the earlier experiments via FEA. Further, we propose a method to calculate the crack width. We also propose a formula for the maximum strain of rebar necessary to calculate the crack width.
{"title":"Fracture mechanism of reinforced concrete non-structural wall","authors":"M. Matsubayashi","doi":"10.21012/FC10.235475","DOIUrl":"https://doi.org/10.21012/FC10.235475","url":null,"abstract":"Following recent earthquakes in Japan, there are several reports of damage to nonstructural walls in reinforced concrete buildings, which causes problems for their continued use. Thus, it is important to consider structural strength as well as damages in design. In this paper, we propose a performance design method to evaluate the fracture mechanism of non-structural walls. In other words, we propose a method to evaluate the levels of shear crack (i.e., width, number of cracks, and crack width) to determine the relationship between shear load and deformation. We focus specifically on crack width. First, we conducted an experiment on the walls and investigated the influence of the rebar arrangement on cracks. The shear strength increases, and the crack width was found to decrease when the rebar separation became narrower and the rebar ratio increased. Subsequently, we reproduced the behaviors of the test specimens observed in the earlier experiments via FEA. Further, we propose a method to calculate the crack width. We also propose a formula for the maximum strain of rebar necessary to calculate the crack width.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"27 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":"114208054","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":"Autogenous healing of fibre/matrix interface and its enhancement","authors":"J. Qiu","doi":"10.21012/FC10.233115","DOIUrl":"https://doi.org/10.21012/FC10.233115","url":null,"abstract":"","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"18 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":"115316306","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}
The cyclic creep curve represents the evolution of the maximum strain, ε, versus the number of cycles to failure, N, and it can be used to predict fatigue failure and its scatter. In this kind of curves, two random phenomena are observed. The first one is related to the evolution of ε as the number of cycles increases. It represents the damage progress identified as fatigue creep. Meanwhile, the second phenomenon is referred to the scatter of N, commonly used in fatigue life assessment. From this curve and the phenomena involved, this work proposes a new probabilistic failure criterion for strain-based fatigue in plain and steel-fiber reinforced concrete. It is based on a double normalization, from which these curves fit accurately to a Weibull distribution function of minima. The first normalization is referred to N, meanwhile the second one is related to ε. The proposed methodology allows the entire cyclic creep curve and the definition of the ultimate limit state to be predicted. It is validated with a series of low-cycle fatigue tests of concrete mixes with different amounts of fiber sharing the same concrete matrix.
{"title":"Full normalization of the cyclic creep curve of steel-fiber reinforced concrete","authors":"E. Poveda","doi":"10.21012/FC10.235729","DOIUrl":"https://doi.org/10.21012/FC10.235729","url":null,"abstract":"The cyclic creep curve represents the evolution of the maximum strain, ε, versus the number of cycles to failure, N, and it can be used to predict fatigue failure and its scatter. In this kind of curves, two random phenomena are observed. The first one is related to the evolution of ε as the number of cycles increases. It represents the damage progress identified as fatigue creep. Meanwhile, the second phenomenon is referred to the scatter of N, commonly used in fatigue life assessment. From this curve and the phenomena involved, this work proposes a new probabilistic failure criterion for strain-based fatigue in plain and steel-fiber reinforced concrete. It is based on a double normalization, from which these curves fit accurately to a Weibull distribution function of minima. The first normalization is referred to N, meanwhile the second one is related to ε. The proposed methodology allows the entire cyclic creep curve and the definition of the ultimate limit state to be predicted. It is validated with a series of low-cycle fatigue tests of concrete mixes with different amounts of fiber sharing the same concrete matrix.","PeriodicalId":329531,"journal":{"name":"Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures","volume":"89 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":"123467070","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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