The supplementary cementitious materials (SCMs) have recognized many of the beneficial influences on concrete ability to resist the penetration of chloride ions, such as fly ash, slag, silica fume, metakaolin, and other natural pozzolans; this benefit has primarily been ascribed to the refined pore structure that results from the appropriate use of SCMs, which, in turn, results in reduced permeability and ionic diffusivity. The paper illustrates the state-of-the-art research findings on; (1) the classification of the SCMs and physicochemical properties; (2) the influences of SCMs on cement binder and the pore structure under chloride ion permeability; (3) the influences of the SCMs on the carbonation process of the cement binder that aims to determine the optimum relationship between SCMs and concrete transport properties. The interesting experimental investigations of the combined influence of chloride and carbonate permeation in cement binder that implement the latest methods in different curing conditions, types, and level contents of the SCMs will yield new scientific results and proposals for the industrial applications auxiliary materials.
{"title":"The effect of supplementary cementitious materials on transport properties of cementitious materials - state-of-the-art","authors":"Zaid Abdulhussein, K. Kopecskó","doi":"10.32970/cs.2021.1.4","DOIUrl":"https://doi.org/10.32970/cs.2021.1.4","url":null,"abstract":"The supplementary cementitious materials (SCMs) have recognized many of the beneficial influences on concrete ability to resist the penetration of chloride ions, such as fly ash, slag, silica fume, metakaolin, and other natural pozzolans; this benefit has primarily been ascribed to the refined pore structure that results from the appropriate use of SCMs, which, in turn, results in reduced permeability and ionic diffusivity. The paper illustrates the state-of-the-art research findings on; (1) the classification of the SCMs and physicochemical properties; (2) the influences of SCMs on cement binder and the pore structure under chloride ion permeability; (3) the influences of the SCMs on the carbonation process of the cement binder that aims to determine the optimum relationship between SCMs and concrete transport properties. The interesting experimental investigations of the combined influence of chloride and carbonate permeation in cement binder that implement the latest methods in different curing conditions, types, and level contents of the SCMs will yield new scientific results and proposals for the industrial applications auxiliary materials.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86401748","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}
Concrete is an inhomogeneous building material. It has a considerable and reliable compressive strength and a relative low tensile strength which can be even exhausted locally under unfortunate conditions. It is quite obvious that the concrete tensile strength was always reprehended as the most unreliable concrete property. A simple relationship between tensile- and compressive strength is introduced. The mechanical background of the relation tensile- to compressive strength in case of ‘normal’ and high strength concretes is elucidated. Mechanical bond, too, relies completely on the tensile strength. In the design of structural concrete members the tension fields are more characteristic than the compression fields. Effective concrete strengths are not successful. Tensile strength can be applied as ‘yield condition’ for the lower bound solution in the theory of plasticity. The paper intends to contribute to the acceptance of the tensile strength as the more fundamental concrete characteristics.
{"title":"The tensile strength: The most fundamental mechanical characteristics of concrete","authors":"A. Windisch","doi":"10.32970/cs.2021.1.1","DOIUrl":"https://doi.org/10.32970/cs.2021.1.1","url":null,"abstract":"Concrete is an inhomogeneous building material. It has a considerable and reliable compressive strength and a relative low tensile strength which can be even exhausted locally under unfortunate conditions. It is quite obvious that the concrete tensile strength was always reprehended as the most unreliable concrete property. A simple relationship between tensile- and compressive strength is introduced. The mechanical background of the relation tensile- to compressive strength in case of ‘normal’ and high strength concretes is elucidated. Mechanical bond, too, relies completely on the tensile strength. In the design of structural concrete members the tension fields are more characteristic than the compression fields. Effective concrete strengths are not successful. Tensile strength can be applied as ‘yield condition’ for the lower bound solution in the theory of plasticity. The paper intends to contribute to the acceptance of the tensile strength as the more fundamental concrete characteristics.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83031623","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}
Nowadays, many computer software products are available for the numerical modeling of reinforced concrete structures; however, the accuracy of the numerical models created by the programs can only be accepted with a properly developed and verified modeling procedure. Within the framework of the present article, we present the numerical modeling possibilities of reinforced concrete structural elements and their connections through numerical models made by a modeling procedure we have built. In our studies, we also dealt with quasi-static unidirectional (horizontal and vertical) and cyclically variable direction and magnitude loads. The numerical models were created using the ATENA 3D three-dimensional nonlinear finite element software developed specifically for the study of concrete and reinforced concrete structures. In many cases, the results obtained by numerical experiments were compared with the results obtained by laboratory experiments, and some of our numerical experiments were compared with the results obtained using two-dimensional finite element software. Within the framework of this article, we would like to give a comprehensive picture of the numerical studies we have performed. We have also briefly summarized the results and experiences obtained from 3D nonlinear finite element studies.
{"title":"Modern numerical modeling of reinforced concrete structures","authors":"Zsolt Roszevák, István Haris","doi":"10.32970/cs.2021.1.3","DOIUrl":"https://doi.org/10.32970/cs.2021.1.3","url":null,"abstract":"Nowadays, many computer software products are available for the numerical modeling of reinforced concrete structures; however, the accuracy of the numerical models created by the programs can only be accepted with a properly developed and verified modeling procedure. Within the framework of the present article, we present the numerical modeling possibilities of reinforced concrete structural elements and their connections through numerical models made by a modeling procedure we have built. In our studies, we also dealt with quasi-static unidirectional (horizontal and vertical) and cyclically variable direction and magnitude loads. The numerical models were created using the ATENA 3D three-dimensional nonlinear finite element software developed specifically for the study of concrete and reinforced concrete structures. In many cases, the results obtained by numerical experiments were compared with the results obtained by laboratory experiments, and some of our numerical experiments were compared with the results obtained using two-dimensional finite element software. Within the framework of this article, we would like to give a comprehensive picture of the numerical studies we have performed. We have also briefly summarized the results and experiences obtained from 3D nonlinear finite element studies.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79560935","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 primary application of the notched three point bending test (3PBT) is to determine the fracture energy of concrete. However, the measurement setup is also suitable for determining additional mechanical parameters: flexural tensile strength, modulus of elasticity, and indirectly the compressive strength also. The aim of this paper is to present the calculation methods of the mechanical properties that can be determined from the results of a test series in which mixtures with different types of aggregates were used (quartz, dolomite, limestone, andesite, expanded clay). To validate the obtained results, the parameters determined from the measurements are compared to the formulas of the fib Model Code 2010. A recommendation is also presented for the calculation of the fracture energy by using compressive strength values measured on a half prism.
{"title":"Comparison of the result of notched three point bending test with Model Code 2010 formulas","authors":"V. Hlavicka","doi":"10.32970/cs.2021.1.2","DOIUrl":"https://doi.org/10.32970/cs.2021.1.2","url":null,"abstract":"The primary application of the notched three point bending test (3PBT) is to determine the fracture energy of concrete. However, the measurement setup is also suitable for determining additional mechanical parameters: flexural tensile strength, modulus of elasticity, and indirectly the compressive strength also. The aim of this paper is to present the calculation methods of the mechanical properties that can be determined from the results of a test series in which mixtures with different types of aggregates were used (quartz, dolomite, limestone, andesite, expanded clay). To validate the obtained results, the parameters determined from the measurements are compared to the formulas of the fib Model Code 2010. A recommendation is also presented for the calculation of the fracture energy by using compressive strength values measured on a half prism.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87021811","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 : 2021-01-01Epub Date: 2021-02-04DOI: 10.1186/s40069-020-00450-9
Bashar Hariri, Lan Lin
The purpose of this study is to examine the effects of the seismic wave velocity on vertical displacement of a cable-stayed bridge's deck under asynchronous excitation. The Quincy Bayview Bridge located in Illinois, USA, and four other generic bridges are selected for the study. Ten records obtained from earthquakes in US, Japan, and Taiwan are used as input for the seismic excitation in the time-history analysis. Two equations are proposed in this study to determine a critical seismic wave velocity that would produce the greatest vertical deck displacement. The critical wave velocity depends on the total length of the bridge, the fundamental period of the bridge, and the C-factor. The C-factor in this study is 0.72, which is based on analyzed results from the five selected bridges. The two equations and the C-factor are verified through application on two 3-span cable-stayed bridges studied previously by Nazmy and Abdel-Ghaffar. The proposed C-factor of 0.72 is recommended for use for typical 3-span cable-stayed bridges with a side-to-main span ratio of about 0.48. The methodology developed in the study, however, can be applied to any specific bridge to examine the excitation of the deck vertical displacement under the longitudinal seismic ground motion.
{"title":"Estimating a Seismic Wave Velocity for Exciting the Greatest Anticipated Vertical Deck Displacement of a Cable-Stayed Bridge Subjected to Asynchronous Excitation.","authors":"Bashar Hariri, Lan Lin","doi":"10.1186/s40069-020-00450-9","DOIUrl":"https://doi.org/10.1186/s40069-020-00450-9","url":null,"abstract":"<p><p>The purpose of this study is to examine the effects of the seismic wave velocity on vertical displacement of a cable-stayed bridge's deck under asynchronous excitation. The Quincy Bayview Bridge located in Illinois, USA, and four other generic bridges are selected for the study. Ten records obtained from earthquakes in US, Japan, and Taiwan are used as input for the seismic excitation in the time-history analysis. Two equations are proposed in this study to determine a critical seismic wave velocity that would produce the greatest vertical deck displacement. The critical wave velocity depends on the total length of the bridge, the fundamental period of the bridge, and the <i>C-factor</i>. The <i>C-factor</i> in this study is 0.72, which is based on analyzed results from the five selected bridges. The two equations and the <i>C-factor</i> are verified through application on two 3-span cable-stayed bridges studied previously by Nazmy and Abdel-Ghaffar. The proposed C-factor of 0.72 is recommended for use for typical 3-span cable-stayed bridges with a side-to-main span ratio of about 0.48. The methodology developed in the study, however, can be applied to any specific bridge to examine the excitation of the deck vertical displacement under the longitudinal seismic ground motion.</p>","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40069-020-00450-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25371947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of Fibre Reinforced Concrete (FRC) is widely accepted in the tunnelling industry. The generally accepted method to determine the material parameters of FRC is the standard 3-point beam test. The effect of age can be relevant for tunnels, because these structures are usually designed for life cycles over 100 years. In this paper the test results of FRC specimens with different fibres using different testing methods (beam and square panel) at different ages will be presented. FRC changes its properties over time in case of both fibre types. The post crack capacity of steel FRC increases in beam tests, while it decreases in panel tests, which yields the conclusion that steel fibres work better at smaller crack width. This changes only a small amount over time. The energy absorption measured from panel tests reduces in case of steel fibre, but stays at a constant level for synthetic fibre.
{"title":"The effect of age and testing method on the added fracture energy of fibre reinforced concrete","authors":"K. Juhász, P. Schaul","doi":"10.32970/CS.2019.1.4","DOIUrl":"https://doi.org/10.32970/CS.2019.1.4","url":null,"abstract":"The use of Fibre Reinforced Concrete (FRC) is widely accepted in the tunnelling industry. The generally accepted method to determine the material parameters of FRC is the standard 3-point beam test. The effect of age can be relevant for tunnels, because these structures are usually designed for life cycles over 100 years. In this paper the test results of FRC specimens with different fibres using different testing methods (beam and square panel) at different ages will be presented. FRC changes its properties over time in case of both fibre types. The post crack capacity of steel FRC increases in beam tests, while it decreases in panel tests, which yields the conclusion that steel fibres work better at smaller crack width. This changes only a small amount over time. The energy absorption measured from panel tests reduces in case of steel fibre, but stays at a constant level for synthetic fibre.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85269978","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}
Due to the recent demand for water supply developments in Hungary two types of water towers made of prefabricated elements have been developed for lower storage capacities, from 50 m3 up to 750 m3. The paper summarizes the design aspects and also the experiences obtained during the construction of five new water towers of various capacities in this range having been realized, so far. Although the application of steel towers in lower storage ranges has been regarded more typical, the realization of prefabricated concrete water towers has proved to be favourable and economic as well.
{"title":"Prefab water towers for lower storage capacities","authors":"B. Csíki, Károly Kôszeghy","doi":"10.32970/CS.2019.1.3","DOIUrl":"https://doi.org/10.32970/CS.2019.1.3","url":null,"abstract":"Due to the recent demand for water supply developments in Hungary two types of water towers made of prefabricated elements have been developed for lower storage capacities, from 50 m3 up to 750 m3. The paper summarizes the design aspects and also the experiences obtained during the construction of five \u0000new water towers of various capacities in this range having been realized, so far. Although the application of steel towers in lower storage ranges has been regarded more typical, the realization of prefabricated concrete water towers has proved to be favourable and economic as well.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82597972","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 failure models developed until the 1960ies were defined by the testing equipment: the triaxial loading cell which was developed at the beginning of the last century by Karman. The axial loading was performed with a solid loading plate, the central-symmetric transverse loading through hydraulic pressure. Therefore, the characterization of the failure surface with the hydrostatic normal stress and octahedral shear stress without any reference to deformations was a logical consequence. In 1963 Hilsdorf proposed a brush-type loading equipment. Using brushes Kupfer carried out his wellknown biaxial loading tests which made possible the characterization of concrete strength by means of the principal stresses. In 1977 Ottosen applied in his model for multiaxial strength of concrete the stress invariants. The same did CEB in the Bulletin d’Information N°. 156. Van Mier (1984) applied brushes and proposed a 3D-type representation using contour lines. The MC2010 returned to the Ottosen model and declared concrete as frictional material. Using the principal stresses, a new, transparent (and physically really sound) form of representation of the failure surface showing the strength increase due to bi- and triaxial loading is presented.
直到20世纪60年代发展起来的破坏模式都是通过测试设备来定义的:上世纪初由卡门公司开发的三轴加载箱。轴向加载采用固体加载板，中心对称横向加载采用液压加载。因此，在不考虑变形的情况下，用静水法向应力和八面体剪应力来表征破坏面是顺理成章的。1963年希尔斯多夫提出了一种刷式装载设备。Kupfer使用刷子进行了他著名的双轴加载试验，这使得通过主应力来表征混凝土强度成为可能。1977年，奥托森在他的混凝土多轴强度模型中应用了应力不变量。行政首长协调会在《新闻公报》中也做了同样的工作。156. Van Mier(1984)使用笔刷，并提出了使用等高线的3d型表示。MC2010回到Ottosen模型，并宣布混凝土为摩擦材料。利用主应力，提出了一种新的、透明的(物理上真正合理的)破坏面表示形式，显示了由于双轴和三轴加载而导致的强度增加。
{"title":"Kármán and the development of the material models of concrete","authors":"A. Windisch","doi":"10.32970/CS.2019.1.1","DOIUrl":"https://doi.org/10.32970/CS.2019.1.1","url":null,"abstract":"The failure models developed until the 1960ies were defined by the testing equipment: the triaxial loading cell which was developed at the beginning of the last century by Karman. The axial loading was performed with a solid loading plate, the central-symmetric transverse loading through hydraulic pressure. Therefore, the characterization of the failure surface with the hydrostatic normal stress and octahedral shear stress without any reference to deformations was a logical consequence. In 1963 Hilsdorf proposed a brush-type loading equipment. Using brushes Kupfer carried out his wellknown biaxial loading tests which made possible the characterization of concrete strength by means of the principal stresses. In 1977 Ottosen applied in his model for multiaxial strength of concrete the stress invariants. The same did CEB in the Bulletin d’Information N°. 156. Van Mier (1984) applied brushes and proposed a 3D-type representation using contour lines. The MC2010 returned to the Ottosen model and declared concrete as frictional material. Using the principal stresses, a new, transparent (and physically really sound) form of representation of the failure surface showing the strength increase due to bi- and triaxial loading is presented.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75841526","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}
Analysis of aircraft impact is required for newly designed nuclear power plant containments, that are typically robust reinforced concrete (RC) or prestressed concrete structures. In our paper we shortly summarize the main function of containments and show some typical examples for their structural arrangement. From the point of view of the impact we show the typical effects of an aircraft impact and the analysis methods of it. In the second part of the paper a preliminary analysis for aircraft impact into a prestressed concrete containment building is executed with different methods and with a military jet and a large passenger aircraft. At the end results of the analysis are evaluated and suggestions for more detailed modelling are made.
{"title":"Preliminary analysis of an rc containment structure subjected to aircraft-impact","authors":"L. Hlavicka-Laczák, G. Farkas","doi":"10.32970/cs.2019.1.2","DOIUrl":"https://doi.org/10.32970/cs.2019.1.2","url":null,"abstract":"Analysis of aircraft impact is required for newly designed nuclear power plant containments, that are typically robust reinforced concrete (RC) or prestressed concrete structures. In our paper we shortly summarize the main function of containments and show some typical examples for their structural arrangement. From the point of view of the impact we show the typical effects of an aircraft impact and the analysis methods of it. In the second part of the paper a preliminary analysis for aircraft impact into a prestressed concrete containment building is executed with different methods and with a military jet and a large passenger aircraft. At the end results of the analysis are evaluated and suggestions for more detailed modelling are made.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83333212","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 : 2018-10-08DOI: 10.4324/9780203476390_CHAPTER_12
Betonvereniging, Deutscher Beton-Verein
{"title":"Control of cracking","authors":"Betonvereniging, Deutscher Beton-Verein","doi":"10.4324/9780203476390_CHAPTER_12","DOIUrl":"https://doi.org/10.4324/9780203476390_CHAPTER_12","url":null,"abstract":"","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75727729","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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