Pub Date : 2021-08-18DOI: 10.1080/13287982.2021.1962618
S. Gopinath, N. Iyer, R. Gettu
ABSTRACT Textile reinforced concrete (TRC) is a promising material for strengthening of reinforced concrete beams due to the possibility of customizing both textile and matrix to achieve the targeted strain hardening under tensile load. Considering the complexity involved in material behaviour of TRC, the independent material characteristics majorly influence the response of the strengthened system. Presently, simple mathematical prediction models for TRC strengthened systems are few. The objective of this paper is to propose a simplified non-iterative approach to predict the behavior of RC beams strengthened with TRC. The material response calibrated based on experimental data of RC and TRC is used to develop the model using two material properties and ten non-dimensional parameters. The material parameters are described using Young´s modulus and first-crack strain of TRC in addition to various non-dimensional parameters that define strain hardening of TRC, tensile strength of steel, compressive strength of concrete and ultimate strain levels. The strain hardening of TRC is accurately incorporated, and the appropriate failure criteria for the strengthened system are idealized. Curvature at a particular section is calculated by using strain values. Parametric studies revealed that the material nonlinearity is adequately addressed and salient stages of the strengthened system predicted till failure.
{"title":"Non-Iterative Model for Analysis of RC Beams Strengthened with Textile Reinforced Concrete","authors":"S. Gopinath, N. Iyer, R. Gettu","doi":"10.1080/13287982.2021.1962618","DOIUrl":"https://doi.org/10.1080/13287982.2021.1962618","url":null,"abstract":"ABSTRACT Textile reinforced concrete (TRC) is a promising material for strengthening of reinforced concrete beams due to the possibility of customizing both textile and matrix to achieve the targeted strain hardening under tensile load. Considering the complexity involved in material behaviour of TRC, the independent material characteristics majorly influence the response of the strengthened system. Presently, simple mathematical prediction models for TRC strengthened systems are few. The objective of this paper is to propose a simplified non-iterative approach to predict the behavior of RC beams strengthened with TRC. The material response calibrated based on experimental data of RC and TRC is used to develop the model using two material properties and ten non-dimensional parameters. The material parameters are described using Young´s modulus and first-crack strain of TRC in addition to various non-dimensional parameters that define strain hardening of TRC, tensile strength of steel, compressive strength of concrete and ultimate strain levels. The strain hardening of TRC is accurately incorporated, and the appropriate failure criteria for the strengthened system are idealized. Curvature at a particular section is calculated by using strain values. Parametric studies revealed that the material nonlinearity is adequately addressed and salient stages of the strengthened system predicted till failure.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"66 1","pages":"277 - 288"},"PeriodicalIF":1.1,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77957434","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 : 2021-08-11DOI: 10.1080/13287982.2021.1964207
M. Shirinzadeh, A. Haghollahi, Hassan Gomar
ABSTRACT High potential for progressive collapse is one of the main weaknesses of structural frames with simple connections. Therefore, strengthening of this structural system is a necessity for both existing and new structures. In this study, the current simple connection with double web angles and one seat angle is modified by using dampers and a bracket-tendon system. The proposed methods of improvement increase the connection performance against progressive collapse due to column removal significantly, while they hardly change the stiffness and rigidity of the connections. Finite element software, ABAQUS, is used for this assessment. Vertical displacement of the modified connections after removal of the column is compared as an evaluation criterion. The results indicate that the bracket-tendon system is quite effective in reduction of vertical displacement of the connection up to 46%, and applying of dampers enhances the performance of the connections notably from 20% to 58%.
{"title":"Simple connections retrofitted by dampers and bracket-tendon system against progressive collapse","authors":"M. Shirinzadeh, A. Haghollahi, Hassan Gomar","doi":"10.1080/13287982.2021.1964207","DOIUrl":"https://doi.org/10.1080/13287982.2021.1964207","url":null,"abstract":"ABSTRACT High potential for progressive collapse is one of the main weaknesses of structural frames with simple connections. Therefore, strengthening of this structural system is a necessity for both existing and new structures. In this study, the current simple connection with double web angles and one seat angle is modified by using dampers and a bracket-tendon system. The proposed methods of improvement increase the connection performance against progressive collapse due to column removal significantly, while they hardly change the stiffness and rigidity of the connections. Finite element software, ABAQUS, is used for this assessment. Vertical displacement of the modified connections after removal of the column is compared as an evaluation criterion. The results indicate that the bracket-tendon system is quite effective in reduction of vertical displacement of the connection up to 46%, and applying of dampers enhances the performance of the connections notably from 20% to 58%.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"35 1","pages":"289 - 298"},"PeriodicalIF":1.1,"publicationDate":"2021-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88673660","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 : 2021-08-04DOI: 10.1080/13287982.2021.1962489
Enas Al-Faqra, Y. Murad, Mu'tasim Abdel Jaber, Nasim Shatarat
ABSTRACT The torsional behaviour of high-strength concrete beams that are transversely reinforced with continuous spiral reinforcement is experimentally investigated in this research. Seventeen specimens are divided into four groups according to their concrete strength: 25, 50, 60, and 70 MPa. Two types of transverse reinforcement, including closed and spiral stirrups, are used at a transverse spacing of 75 and 125 mm for each group. Test results are compared to the analytical values predicted using the ACI equation. Test results have shown an enhancement in the ultimate torsional capacity for the specimens made with high strength concrete compared to those made using normal strength concrete. The enhancement percentage ranges from 1.4% to 46.3%. In addition, results have shown an enhancement in the ultimate torsional capacity for specimens reinforced with spiral reinforcement compared to specimens made with conventional closed stirrups. The enhancement percentage varies from 8.3% to 34.6%. The study concluded that utilising continuous spiral reinforcement would result in higher ultimate torsional capacity than traditional closed stirrups for the same strength of concrete and that the torsion equations of ACI-318 M-19 are applicable and conservative for high strength concrete with a continuous spiral reinforcement.
{"title":"Torsional behaviour of high strength concrete beams with spiral reinforcement","authors":"Enas Al-Faqra, Y. Murad, Mu'tasim Abdel Jaber, Nasim Shatarat","doi":"10.1080/13287982.2021.1962489","DOIUrl":"https://doi.org/10.1080/13287982.2021.1962489","url":null,"abstract":"ABSTRACT The torsional behaviour of high-strength concrete beams that are transversely reinforced with continuous spiral reinforcement is experimentally investigated in this research. Seventeen specimens are divided into four groups according to their concrete strength: 25, 50, 60, and 70 MPa. Two types of transverse reinforcement, including closed and spiral stirrups, are used at a transverse spacing of 75 and 125 mm for each group. Test results are compared to the analytical values predicted using the ACI equation. Test results have shown an enhancement in the ultimate torsional capacity for the specimens made with high strength concrete compared to those made using normal strength concrete. The enhancement percentage ranges from 1.4% to 46.3%. In addition, results have shown an enhancement in the ultimate torsional capacity for specimens reinforced with spiral reinforcement compared to specimens made with conventional closed stirrups. The enhancement percentage varies from 8.3% to 34.6%. The study concluded that utilising continuous spiral reinforcement would result in higher ultimate torsional capacity than traditional closed stirrups for the same strength of concrete and that the torsion equations of ACI-318 M-19 are applicable and conservative for high strength concrete with a continuous spiral reinforcement.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"57 1","pages":"266 - 276"},"PeriodicalIF":1.1,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81343118","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 : 2021-07-29DOI: 10.1080/13287982.2021.1958507
K. Jaafar
ABSTRACT Common transverse reinforcement of reinforced concrete members with circular cross-section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both shear enabler and confiner for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required. The validity of concepts which underlines current methods for shear design used in design codes will be investigated in this paper especially for beams with the shear configuration used, which violates basic code rules in truss formation. A simplified model based on sectional crack analysis for assessing spiral shear contribution is proposed for practical design consideration.
{"title":"Testing the applicability of design code provisions - case of unconventional shear reinforcement","authors":"K. Jaafar","doi":"10.1080/13287982.2021.1958507","DOIUrl":"https://doi.org/10.1080/13287982.2021.1958507","url":null,"abstract":"ABSTRACT Common transverse reinforcement of reinforced concrete members with circular cross-section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both shear enabler and confiner for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required. The validity of concepts which underlines current methods for shear design used in design codes will be investigated in this paper especially for beams with the shear configuration used, which violates basic code rules in truss formation. A simplified model based on sectional crack analysis for assessing spiral shear contribution is proposed for practical design consideration.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"45 1","pages":"251 - 265"},"PeriodicalIF":1.1,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85289825","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 : 2021-07-03DOI: 10.1080/13287982.2021.1954306
S. Menegon, H. Tsang, John L. Wilson, N. Lam
ABSTRACT Displacement-based methods, such as a non-linear static pushover analysis (e.g. the capacity spectrum method), have many advantages compared to traditional force-based design methods. However, implementing a non-linear analysis and design method in accordance with the Australian Standard for concrete structures (AS 3600) introduces many difficult technical issues into the design, of which the standard provides little guidance. The aim of this study is to provide a framework and general guidance for designers who wish to perform non-linear displacement-based analysis methods for RC wall buildings. The paper will present how these methods can be used in accordance with the Australian Standard for earthquake actions (AS 1170.4) to assess seismic compliance and then provide recommendations for the requirements stipulated by AS 3600, which includes an experimentally validated tension stiffening model, nonlinear stress-strain material curves, mean material properties and material strain limits. The paper is concluded with a case study example of how a displacement-based seismic assessment can be performed using a typical case study building.
{"title":"RC walls in Australia: displacement-based seismic design in accordance with AS 1170.4 and AS 3600","authors":"S. Menegon, H. Tsang, John L. Wilson, N. Lam","doi":"10.1080/13287982.2021.1954306","DOIUrl":"https://doi.org/10.1080/13287982.2021.1954306","url":null,"abstract":"ABSTRACT Displacement-based methods, such as a non-linear static pushover analysis (e.g. the capacity spectrum method), have many advantages compared to traditional force-based design methods. However, implementing a non-linear analysis and design method in accordance with the Australian Standard for concrete structures (AS 3600) introduces many difficult technical issues into the design, of which the standard provides little guidance. The aim of this study is to provide a framework and general guidance for designers who wish to perform non-linear displacement-based analysis methods for RC wall buildings. The paper will present how these methods can be used in accordance with the Australian Standard for earthquake actions (AS 1170.4) to assess seismic compliance and then provide recommendations for the requirements stipulated by AS 3600, which includes an experimentally validated tension stiffening model, nonlinear stress-strain material curves, mean material properties and material strain limits. The paper is concluded with a case study example of how a displacement-based seismic assessment can be performed using a typical case study building.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"36 1","pages":"205 - 221"},"PeriodicalIF":1.1,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79447910","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 : 2021-07-03DOI: 10.1080/13287982.2021.1946993
S. Menegon, H. Tsang, John L. Wilson, N. Lam
ABSTRACT This paper presents a statistical analysis of the actual mean material properties for typical grades of concrete and reinforcement available in Australia. The analysis was performed using a database of 3,447 concrete cylinder test results and 15,201 reinforcement tensile test results. The test results were taken over a period from 2009 to 2021. The paper provides a summary of the mean values and respective coefficient of variation values for the different grades of concrete and reinforcement that make up the database. Distinctive manufacturing trends and variability between suppliers were observed for reinforcement samples and appropriate recommendations have been proposed. Researchers or designers can adopt these values to undertake probabilistic assessments of RC structures. The paper also provides recommendations for mean material properties for the purpose of undertaking non-linear analysis of RC structures. The database of test results also includes early age strength data for concrete, which have been used to provide recommendations for predicting the early age strength of various standard grades of concrete available in Australia. The paper also presents an assessment of the theoretical characteristic values from the database for the various grades of reinforcement and concrete and how they compare to respective specified code requirements.
{"title":"Statistical analysis of material properties and recommended values for the assessment of RC structures in Australia","authors":"S. Menegon, H. Tsang, John L. Wilson, N. Lam","doi":"10.1080/13287982.2021.1946993","DOIUrl":"https://doi.org/10.1080/13287982.2021.1946993","url":null,"abstract":"ABSTRACT This paper presents a statistical analysis of the actual mean material properties for typical grades of concrete and reinforcement available in Australia. The analysis was performed using a database of 3,447 concrete cylinder test results and 15,201 reinforcement tensile test results. The test results were taken over a period from 2009 to 2021. The paper provides a summary of the mean values and respective coefficient of variation values for the different grades of concrete and reinforcement that make up the database. Distinctive manufacturing trends and variability between suppliers were observed for reinforcement samples and appropriate recommendations have been proposed. Researchers or designers can adopt these values to undertake probabilistic assessments of RC structures. The paper also provides recommendations for mean material properties for the purpose of undertaking non-linear analysis of RC structures. The database of test results also includes early age strength data for concrete, which have been used to provide recommendations for predicting the early age strength of various standard grades of concrete available in Australia. The paper also presents an assessment of the theoretical characteristic values from the database for the various grades of reinforcement and concrete and how they compare to respective specified code requirements.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"35 1","pages":"191 - 204"},"PeriodicalIF":1.1,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79877920","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 : 2021-07-03DOI: 10.1080/13287982.2021.1957553
Nadiah Loqman, N. A. Safiee, Wong Hui Kah, N. Abu Bakar, N. A. Mohd. Nasir
ABSTRACT The complexity of concrete and steel in composite beam has been addressed in many studies previously. However, the use of precast concrete slab in steel–concrete composite construction is considered as new, hence many factors that affect its behaviour need to be investigated. It becomes interesting when the application of interlocking tongue and groove joints between precast concrete slabs is introduced. For this purpose, a performance comparison between normal precast slab and interlocking tongue and groove precast slab in composite construction is conducted using finite element analysis. Both are designed to have full composite action using bolted shear connector. In this research, a total of five models including a control model were developed to study the flexural behaviour of designated composite beam. The model has been verified against experimental results, which showed a good agreement . Parametric studies were performed to investigate the effects of bolt size and height on flexural behaviour of the beam. The present study demonstrated that the presence of interlocking joints between slabs with larger diameter bolt can efficiently improve the stiffness of the composite system.
{"title":"Behaviour of interlocking concrete slab and steel composite beam incorporated bolt shear connector","authors":"Nadiah Loqman, N. A. Safiee, Wong Hui Kah, N. Abu Bakar, N. A. Mohd. Nasir","doi":"10.1080/13287982.2021.1957553","DOIUrl":"https://doi.org/10.1080/13287982.2021.1957553","url":null,"abstract":"ABSTRACT The complexity of concrete and steel in composite beam has been addressed in many studies previously. However, the use of precast concrete slab in steel–concrete composite construction is considered as new, hence many factors that affect its behaviour need to be investigated. It becomes interesting when the application of interlocking tongue and groove joints between precast concrete slabs is introduced. For this purpose, a performance comparison between normal precast slab and interlocking tongue and groove precast slab in composite construction is conducted using finite element analysis. Both are designed to have full composite action using bolted shear connector. In this research, a total of five models including a control model were developed to study the flexural behaviour of designated composite beam. The model has been verified against experimental results, which showed a good agreement . Parametric studies were performed to investigate the effects of bolt size and height on flexural behaviour of the beam. The present study demonstrated that the presence of interlocking joints between slabs with larger diameter bolt can efficiently improve the stiffness of the composite system.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"18 1","pages":"236 - 249"},"PeriodicalIF":1.1,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74264649","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 : 2021-07-03DOI: 10.1080/13287982.2021.1957198
Kambiz Takin, R. Doroudi, Siyamak Doroudi
ABSTRACT This study concentrates on applying semi-active dampers to control structures. In this paper, fuzzy algorithm types 1 and 2 have been used as controllers to evaluate the voltage of semi-active dampers. To design a proper fuzzy logic controller, membership functions and suitable rule sets need to be tuned and extracted. The location of a semi-active damper is very significant to reduce the responses of structure. In this paper, a 15-story building’s responses for both uncontrolled and controlled (with MR dampers) situations subject to different ground motions are evaluated. Type 1 and type 2 fuzzy logic controllers, and the location of three MR dampers are optimised by Grey Wolf Optimiser, and also dissipating energies are investigated. The results show that although both optimised controllers can successfully reduce the seismic response of the building, the performance of the fuzzy type 2 controller is slightly superior than type 1. It is confirmed that the best location for dampers would be in the upper stories.
{"title":"Vibration control of structure by optimising the placement of semi-active dampers and fuzzy logic controllers","authors":"Kambiz Takin, R. Doroudi, Siyamak Doroudi","doi":"10.1080/13287982.2021.1957198","DOIUrl":"https://doi.org/10.1080/13287982.2021.1957198","url":null,"abstract":"ABSTRACT This study concentrates on applying semi-active dampers to control structures. In this paper, fuzzy algorithm types 1 and 2 have been used as controllers to evaluate the voltage of semi-active dampers. To design a proper fuzzy logic controller, membership functions and suitable rule sets need to be tuned and extracted. The location of a semi-active damper is very significant to reduce the responses of structure. In this paper, a 15-story building’s responses for both uncontrolled and controlled (with MR dampers) situations subject to different ground motions are evaluated. Type 1 and type 2 fuzzy logic controllers, and the location of three MR dampers are optimised by Grey Wolf Optimiser, and also dissipating energies are investigated. The results show that although both optimised controllers can successfully reduce the seismic response of the building, the performance of the fuzzy type 2 controller is slightly superior than type 1. It is confirmed that the best location for dampers would be in the upper stories.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"56 1","pages":"222 - 235"},"PeriodicalIF":1.1,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91011525","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 : 2021-06-11DOI: 10.1080/13287982.2021.1926062
H. Milner
ABSTRACT This paper describes a relatively simple closed form formula for predicting the strength of glulam assemblies in bending about the major axis based on statistical engineering mechanics using the tension strength of finger jointed of bonded lamination pairs. It has been calibrated against the strengths of full-size glulam beams ranging in depths from 150 mm to 1200 mm over spans of 2.7 m up to 19.5 m. Comparisons are made at both the mean strength and 5th percentile strength levels with the latter drawing attention to the fact that all test series invariably involve observation of minimum values that means the statistical distributions are invariably truncated. For Weibull distributions, this has an impact on the shape factor and, therefore, the local coefficient of variation of the lower tail, which plays an important role in size effects in glulam and potentially has wider implications.
{"title":"Glulam – closed form solution using statistical smearing, truncating, calibrating","authors":"H. Milner","doi":"10.1080/13287982.2021.1926062","DOIUrl":"https://doi.org/10.1080/13287982.2021.1926062","url":null,"abstract":"ABSTRACT This paper describes a relatively simple closed form formula for predicting the strength of glulam assemblies in bending about the major axis based on statistical engineering mechanics using the tension strength of finger jointed of bonded lamination pairs. It has been calibrated against the strengths of full-size glulam beams ranging in depths from 150 mm to 1200 mm over spans of 2.7 m up to 19.5 m. Comparisons are made at both the mean strength and 5th percentile strength levels with the latter drawing attention to the fact that all test series invariably involve observation of minimum values that means the statistical distributions are invariably truncated. For Weibull distributions, this has an impact on the shape factor and, therefore, the local coefficient of variation of the lower tail, which plays an important role in size effects in glulam and potentially has wider implications.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"35 2 1","pages":"165 - 176"},"PeriodicalIF":1.1,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84684711","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 : 2021-06-09DOI: 10.1080/13287982.2021.1935426
S. Sajjadi, R. Madandoust
ABSTRACT Since the existence of cracks reduces the concrete service life, the self-healing ability of concrete has attracted the attention of researchers. In this article, effects of fly ash and steel/polypropylene fibres on the self-healing ability of concrete were investigated separately and together. The cylindrical specimens were pre-cracked by means of a tensile strength test at 28 days. Secondary tensile test was performed immediately after pre-cracking and 28 and 56 days after re-curing in water. Also, to monitor microcracks in concrete after pre-cracking and during the self-healing period, the ultrasonic pulse velocity and permeability tests were conducted. The results showed that 15% fly ash replacement led to 94% reduction in permeability and almost complete recovery in secondary tensile strength after 8 weeks of re-curing. Although the specimen with polypropylene lost lower tensile strength among specimens with fibre immediately after pre-loading (22%), the improvement rate of those during the self-healing period was only 27%.
{"title":"Evaluation of self-healing performance of concrete containing fly ash and fibres","authors":"S. Sajjadi, R. Madandoust","doi":"10.1080/13287982.2021.1935426","DOIUrl":"https://doi.org/10.1080/13287982.2021.1935426","url":null,"abstract":"ABSTRACT Since the existence of cracks reduces the concrete service life, the self-healing ability of concrete has attracted the attention of researchers. In this article, effects of fly ash and steel/polypropylene fibres on the self-healing ability of concrete were investigated separately and together. The cylindrical specimens were pre-cracked by means of a tensile strength test at 28 days. Secondary tensile test was performed immediately after pre-cracking and 28 and 56 days after re-curing in water. Also, to monitor microcracks in concrete after pre-cracking and during the self-healing period, the ultrasonic pulse velocity and permeability tests were conducted. The results showed that 15% fly ash replacement led to 94% reduction in permeability and almost complete recovery in secondary tensile strength after 8 weeks of re-curing. Although the specimen with polypropylene lost lower tensile strength among specimens with fibre immediately after pre-loading (22%), the improvement rate of those during the self-healing period was only 27%.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"19 1","pages":"177 - 190"},"PeriodicalIF":1.1,"publicationDate":"2021-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87174734","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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