Presented is an experimental investigation on the effect of polyvinyl alcohol (PVA) polymer modified alkali resistance (AR) glass fiber reinforced cementitious composites. Series of tensile and flexural tests were performed to evaluate the performance of alkali resistant glass fibers in blended cementitious matrix. Specimens with different amounts of PVA polymer were tested, and specimens under dry air and moist curing environment were compared. Test results are discussed and analyzed.
{"title":"PVA Polymer Modified Glass Fiber Reinforced Cementitious Composites","authors":"Zongjin Li, A. C. P. Liu, C. Leung","doi":"10.14359/12265","DOIUrl":"https://doi.org/10.14359/12265","url":null,"abstract":"Presented is an experimental investigation on the effect of polyvinyl alcohol (PVA) polymer modified alkali resistance (AR) glass fiber reinforced cementitious composites. Series of tensile and flexural tests were performed to evaluate the performance of alkali resistant glass fibers in blended cementitious matrix. Specimens with different amounts of PVA polymer were tested, and specimens under dry air and moist curing environment were compared. Test results are discussed and analyzed.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126982559","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 experimentally evaluated behavior of high performance fiber reinforced concrete (HPFRC) members that exhibit features particularly desirable for increasing earthquake resistance such as high tensile strength and ductility. The seismic response of a four story high performance composite frame (HPCF) building is investigated analytically and compared to that of a seismically designed reinforced concrete frame. HPCF reached an overall good seismic response. As compared to the reference building, it exhibited slower strength and stiffness degradation, lower top displacement and story drifts.
{"title":"Development and Seismic Behavior of High-Performance Composite Frames","authors":"N. Krstulovic-Opara, Kilar","doi":"10.14359/12269","DOIUrl":"https://doi.org/10.14359/12269","url":null,"abstract":"This paper presents experimentally evaluated behavior of high performance fiber reinforced concrete (HPFRC) members that exhibit features particularly desirable for increasing earthquake resistance such as high tensile strength and ductility. The seismic response of a four story high performance composite frame (HPCF) building is investigated analytically and compared to that of a seismically designed reinforced concrete frame. HPCF reached an overall good seismic response. As compared to the reference building, it exhibited slower strength and stiffness degradation, lower top displacement and story drifts.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127725169","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 paper presents the results of a study of bond tests performed to evaluate the bond strength and mechanical behavior of the interface between substrate and repair materials. Slabs made of conventional concrete were cast and cured in ambient laboratory environment; the substrate surface was roughened with jackhammers; and the repair materials were cast by shotcreting or cast by hand. Direct tensile and compression tests were performed after 2 and 6 months to evaluate the bond strength and mechanical behavior of the interface between substrate and repair materials. Paper provides test results.
{"title":"Mechanical Behavior of the Interface Between Substrate and Repair Material","authors":"P. Paramasivam, K. Ong, W. Xu","doi":"10.14359/12246","DOIUrl":"https://doi.org/10.14359/12246","url":null,"abstract":"The paper presents the results of a study of bond tests performed to evaluate the bond strength and mechanical behavior of the interface between substrate and repair materials. Slabs made of conventional concrete were cast and cured in ambient laboratory environment; the substrate surface was roughened with jackhammers; and the repair materials were cast by shotcreting or cast by hand. Direct tensile and compression tests were performed after 2 and 6 months to evaluate the bond strength and mechanical behavior of the interface between substrate and repair materials. Paper provides test results.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126208974","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}
Shrinkage is an important consideration in structural design for serviceability and crack width limits. The ability to design concretes with significantly lower shrinkage is, therefore, of great practical importance. This paper analyzes some of the new shrinkage reducing admixtures (SRA) that have been developed to reduce the extent of shrinkage strains. Specifically, the unrestrained or free shrinkage deformation of concrete incorporating two SRAs based on polypropylene glycol formulations are evaluated over a drying period of seven months. Additionally, the effectiveness of a product based on a wax formulation is studied. Companion tests on two base concretes without SRA have also been performed.
{"title":"Study of the Behavior of Concrete with shrinkage Reducing Admixtures Subjected to Long-Term Drying","authors":"R. Gettu, J. Roncero, Miguel A. Martín","doi":"10.14359/12251","DOIUrl":"https://doi.org/10.14359/12251","url":null,"abstract":"Shrinkage is an important consideration in structural design for serviceability and crack width limits. The ability to design concretes with significantly lower shrinkage is, therefore, of great practical importance. This paper analyzes some of the new shrinkage reducing admixtures (SRA) that have been developed to reduce the extent of shrinkage strains. Specifically, the unrestrained or free shrinkage deformation of concrete incorporating two SRAs based on polypropylene glycol formulations are evaluated over a drying period of seven months. Additionally, the effectiveness of a product based on a wax formulation is studied. Companion tests on two base concretes without SRA have also been performed.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"761 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132935397","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":"Concrete for Freshmen","authors":"E. Landis, W. Manion","doi":"10.14359/12273","DOIUrl":"https://doi.org/10.14359/12273","url":null,"abstract":"","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130752542","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 paper describes the Tufts University's School of Engineering program to introduce teamwork to engineering students. The program is designed to develop good habits for functioning as part of a team. Overviews of the five fundamental skills program and teamwork initiative are presented.
{"title":"Improving Effectiveness of Research in the Classroom Through Teamwork","authors":"Daniel Jansen","doi":"10.14359/12275","DOIUrl":"https://doi.org/10.14359/12275","url":null,"abstract":"The paper describes the Tufts University's School of Engineering program to introduce teamwork to engineering students. The program is designed to develop good habits for functioning as part of a team. Overviews of the five fundamental skills program and teamwork initiative are presented.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127517176","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 addition of small amounts of fiber reinforcement is an alternative for producing high strength concrete with significantly improved durability that industry is demanding. Carbon fiber reinforced concrete in particular has shown to have excellent durability properties due to the fiber's high resistance to wear, heat and corrosion. This paper presents the results of some fundamental investigations on the bulk electrical properties of carbon fiber cement composites under compressive loading. The resistance behavior was evaluated for various fiber volume contents, and the effects of taking resistance measurements both parallel and perpendicular to the axis of loading were investigated.
{"title":"Electrical Resistance of Carbon Fiber Cement Composites Under Compression","authors":"Farhad Reza, G. Batson, J. Yamamuro, J. Lee","doi":"10.14359/12267","DOIUrl":"https://doi.org/10.14359/12267","url":null,"abstract":"The addition of small amounts of fiber reinforcement is an alternative for producing high strength concrete with significantly improved durability that industry is demanding. Carbon fiber reinforced concrete in particular has shown to have excellent durability properties due to the fiber's high resistance to wear, heat and corrosion. This paper presents the results of some fundamental investigations on the bulk electrical properties of carbon fiber cement composites under compressive loading. The resistance behavior was evaluated for various fiber volume contents, and the effects of taking resistance measurements both parallel and perpendicular to the axis of loading were investigated.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130182717","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}
Paper presents a review of some of the Australian code developments in the design of concrete structures. Topics such as shear design of beams, deflection control, punching shear strength of slabs and shear strength of walls are discussed.
{"title":"Some Australian Code Developments in the Design of Concrete Structures","authors":"B. Rangan","doi":"10.14359/12249","DOIUrl":"https://doi.org/10.14359/12249","url":null,"abstract":"Paper presents a review of some of the Australian code developments in the design of concrete structures. Topics such as shear design of beams, deflection control, punching shear strength of slabs and shear strength of walls are discussed.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129101340","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 newly developed powerful version of microplane model, labeled model M4, is used to study two basic phenomena in fracturing concrete: the vertex effect, i.e., the tangential stiffness for loading increments to the side of previous radial loading path in the stress space, and the effect of confinement by a steel tube or a spiral on the suppression of softening response of columns. Comparisons with the tests show the microplane model to predict the initial torsional stiffness very closely, while the classical tensorial models with invariants overpredict this stiffness several times. In the tests performed recently, steel tubes of different thicknesses filled by concrete are squashed to about half of their initial length and very large strains with shear angles up to about 70 degree are achieved. Observations and conclusions from the investigations are provided.
{"title":"Vertex Effect and Confinement of Fracturing Concrete Via Microplane Model M4","authors":"Z. Bažant, F. Caner, J. Červenka","doi":"10.14359/12271","DOIUrl":"https://doi.org/10.14359/12271","url":null,"abstract":"A newly developed powerful version of microplane model, labeled model M4, is used to study two basic phenomena in fracturing concrete: the vertex effect, i.e., the tangential stiffness for loading increments to the side of previous radial loading path in the stress space, and the effect of confinement by a steel tube or a spiral on the suppression of softening response of columns. Comparisons with the tests show the microplane model to predict the initial torsional stiffness very closely, while the classical tensorial models with invariants overpredict this stiffness several times. In the tests performed recently, steel tubes of different thicknesses filled by concrete are squashed to about half of their initial length and very large strains with shear angles up to about 70 degree are achieved. Observations and conclusions from the investigations are provided.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121747907","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}
Synopsis: Restrained tests are used to evaluate the risk of early age cracking and the cracking sensitivity of concrete mixtures. One test that has become common in recent years is the active uniaxial restrained test in which the length change due to shrinkage is recovered by applying external load to maintain the concrete sample at constant length. The length change is measured by linear variable differential transformer (LVDT), which is used as the control signal in this test. In such tests, the dog-bone geometry is used to grip the ends. To ensure a fully restrained test, the LVDT response to the loads and to shrinkage should reflect the deformation in the concrete sample. Therefore, the grip-specimen interaction should not interfere with the measurement of deformation, and this depends on the instrumentation and how the LVDT is attached to the concrete specimen. Some experiments in the literature have the LVDT attached to the steel grips, a practice vulnerable to possible error due to the interaction between the grip and the concrete. This study considered two methods of attaching the LVDT. First, the LVDT is attached to the steel grips; second, the LVDT is attached to the concrete within the zone of reduced cross-section. The results indicate that attaching the LVDT to the grips results in errant measurement of the shrinkage stress, creep, and elastic strains due to the grip-specimen interaction. The consequences will be false interpretation of fully restrained shrinkage and creep characteristics because the grip-specimen interaction leads to a partially restrained test. The study suggests mounting the LVDT to the concrete sample away from the grips to achieve a fully restrained test. Results for two concrete mixtures with w/c ratio of 0.51 and 0.56 are discussed for both methods of attaching LVDTs.
{"title":"Grip-Specimen Interaction in Uniaxial Restrained Test","authors":"S. Altoubat, D. Lange","doi":"10.14359/12253","DOIUrl":"https://doi.org/10.14359/12253","url":null,"abstract":"Synopsis: Restrained tests are used to evaluate the risk of early age cracking and the cracking sensitivity of concrete mixtures. One test that has become common in recent years is the active uniaxial restrained test in which the length change due to shrinkage is recovered by applying external load to maintain the concrete sample at constant length. The length change is measured by linear variable differential transformer (LVDT), which is used as the control signal in this test. In such tests, the dog-bone geometry is used to grip the ends. To ensure a fully restrained test, the LVDT response to the loads and to shrinkage should reflect the deformation in the concrete sample. Therefore, the grip-specimen interaction should not interfere with the measurement of deformation, and this depends on the instrumentation and how the LVDT is attached to the concrete specimen. Some experiments in the literature have the LVDT attached to the steel grips, a practice vulnerable to possible error due to the interaction between the grip and the concrete. This study considered two methods of attaching the LVDT. First, the LVDT is attached to the steel grips; second, the LVDT is attached to the concrete within the zone of reduced cross-section. The results indicate that attaching the LVDT to the grips results in errant measurement of the shrinkage stress, creep, and elastic strains due to the grip-specimen interaction. The consequences will be false interpretation of fully restrained shrinkage and creep characteristics because the grip-specimen interaction leads to a partially restrained test. The study suggests mounting the LVDT to the concrete sample away from the grips to achieve a fully restrained test. Results for two concrete mixtures with w/c ratio of 0.51 and 0.56 are discussed for both methods of attaching LVDTs.","PeriodicalId":265574,"journal":{"name":"SP-206: Concrete: Material Science to Application - A Tribute to Surendra P. Shah","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125787192","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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