R. P. Douglas, V. K. Bui, Y. Akkaya, Surendra P. Shah
This paper describes an experimental program that was aimed at investigating the behavior of self-consolidating concrete (SCC) containing Class F fly ash. The fresh state properties of the concrete were assessed using methods of segregation and flow and the rheology of the paste matrix was also characterized and compared with a previously developed paste rheology model. In addition, compressive strength, chloride permeability, and mold-finish were evaluated. The results indicate that it is possible to develop a SCC containing Class F fly ash that is high performing in its fresh state. Furthermore, the addition of fly ash was shown to reduce superplasticizer dosage, increase workability, and increase overall chloride permeability resistance. In addition, it was determined that the difference of densities between the aggregate and matrix influence the results of a previously developed paste rheology model.
{"title":"Properties of Self-Consolidating Concrete Containing Class F Fly Ash: With a Verification of the Minimum Paste Volume Method","authors":"R. P. Douglas, V. K. Bui, Y. Akkaya, Surendra P. Shah","doi":"10.14359/15831","DOIUrl":"https://doi.org/10.14359/15831","url":null,"abstract":"This paper describes an experimental program that was aimed at investigating the behavior of self-consolidating concrete (SCC) containing Class F fly ash. The fresh state properties of the concrete were assessed using methods of segregation and flow and the rheology of the paste matrix was also characterized and compared with a previously developed paste rheology model. In addition, compressive strength, chloride permeability, and mold-finish were evaluated. The results indicate that it is possible to develop a SCC containing Class F fly ash that is high performing in its fresh state. Furthermore, the addition of fly ash was shown to reduce superplasticizer dosage, increase workability, and increase overall chloride permeability resistance. In addition, it was determined that the difference of densities between the aggregate and matrix influence the results of a previously developed paste rheology model.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116128960","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 describes how the stability of highly fluid self-consolidating concrete (SCC) can be achieved by using a viscosity-modifying admixture (VMA). Currently, there are several types of VMAs available in the market place. Three of the most common types are based on cellulose-ethers, biopolymers and synthetic polymers. This paper studied and compared the properties of these three types of VMAs. Specifically, the influence of these three types of VMAs on the properties of self-consolidating concrete (SCC was studied. Particular attention was placed on the influence of each VMA on the following characteristics of the SCC: (1) dose response of high range water reducer (HRWR); (2) dose response of air entraining agent (AEA): (3) stability of the mixture; (4) effects on time of setting; and (5) compressive strength development.
{"title":"The Influence of Viscosity-Modifying Admixture (VMA) on the Performance of Self-Consolidating Concrete (SCC)","authors":"B. Christensen, F. S. Ong","doi":"10.14359/15820","DOIUrl":"https://doi.org/10.14359/15820","url":null,"abstract":"This paper describes how the stability of highly fluid self-consolidating concrete (SCC) can be achieved by using a viscosity-modifying admixture (VMA). Currently, there are several types of VMAs available in the market place. Three of the most common types are based on cellulose-ethers, biopolymers and synthetic polymers. This paper studied and compared the properties of these three types of VMAs. Specifically, the influence of these three types of VMAs on the properties of self-consolidating concrete (SCC was studied. Particular attention was placed on the influence of each VMA on the following characteristics of the SCC: (1) dose response of high range water reducer (HRWR); (2) dose response of air entraining agent (AEA): (3) stability of the mixture; (4) effects on time of setting; and (5) compressive strength development.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121930106","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 describes how the accurate determination of fresh concrete rheology is key in ensuring the production of self-consolidating concrete (SCC) is successful. However, rheometers are used infrequently in the field and empirical test methods are most commonly used to determine SCC workability despite measuring quantities that are related to rheological parameters only in an indirect way, if at all. Instead of using multiple empirical test methods to measure the workability of SCC, it is desirable to use a rheometer in both the laboratory and field to determine the flow properties of SCC quickly. Existing rheometers are generally unsuitable for routine field use because of their large size, high cost, or both. This paper describes the use of the International Center for Aggregates Research (ICAR) rheometer, a low-cost, fully portable device that can measure concrete mixtures ranging in workability from approximately 50 mm in slump to SCC. Laboratory test results of SCC mixtures and field testing experience are presented to demonstrate the validity and practicality of the ICAR rheometer.
{"title":"\"A New, Portable Rheometer for Fresh Self-Consolidating Concrete\"","authors":"E. Koehler, D. Fowler, C. Ferraris, S. Amziane","doi":"10.14359/15837","DOIUrl":"https://doi.org/10.14359/15837","url":null,"abstract":"This paper describes how the accurate determination of fresh concrete rheology is key in ensuring the production of self-consolidating concrete (SCC) is successful. However, rheometers are used infrequently in the field and empirical test methods are most commonly used to determine SCC workability despite measuring quantities that are related to rheological parameters only in an indirect way, if at all. Instead of using multiple empirical test methods to measure the workability of SCC, it is desirable to use a rheometer in both the laboratory and field to determine the flow properties of SCC quickly. Existing rheometers are generally unsuitable for routine field use because of their large size, high cost, or both. This paper describes the use of the International Center for Aggregates Research (ICAR) rheometer, a low-cost, fully portable device that can measure concrete mixtures ranging in workability from approximately 50 mm in slump to SCC. Laboratory test results of SCC mixtures and field testing experience are presented to demonstrate the validity and practicality of the ICAR rheometer.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128158223","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 describes how an experimental investigation was performed in order to determine the hydraulic pressure variation of cementitious based materials (cement paste, limestone paste, concrete, Self compacting concrete (SCC), etc.) during the plastic phase. A method based on measurements of both total lateral pressure and hydraulic pressure, using a novel device was investigated. Just after mixing, a simultaneous drop of both the hydraulic and the total lateral pressures was recorded, followed by a cancellation of total lateral pressure and a negative value of hydraulic pressure. Compared to other standard methods (Vicat, calorimetry, ultrasonic pulse-echo, etc …), the device was able to give simple and direct information about the mechanical state of the material, in situ. The kinetic variation of the hydraulic pressure occurring during the plastic phase of cement pastes using two portland cement fractions and a limestone filler was investigated. To relate the hydraulic pressure measurements with workability, a study on the evolution of the rheology of the cement paste was conducted. The experiments on standard concretes, which had the same free water content as an equivalent cement paste, show a similar hydraulic pressure variation as long as the pressure is positive. This is not the case for SCC where the observed hydraulic pressure variation is slower and the time of zero pressure is delayed compared to the equivalent cement paste. The presence of limestone and the HRWRA is the main reason for this retardation effect. In addition, as soon as the pressure becomes negative, due to the presence of aggregates, a delaying effect on the pressure variation was observed. In the end, field test show that the hydraulic pressure device could be used to monitor the field schedule of successive pouring, setting and demolding.
{"title":"SCC Evolution of Formwork Hydraulic Pressure and Rheological Properties","authors":"S. Amziane, C. Ferraris","doi":"10.14359/15841","DOIUrl":"https://doi.org/10.14359/15841","url":null,"abstract":"This paper describes how an experimental investigation was performed in order to determine the hydraulic pressure variation of cementitious based materials (cement paste, limestone paste, concrete, Self compacting concrete (SCC), etc.) during the plastic phase. A method based on measurements of both total lateral pressure and hydraulic pressure, using a novel device was investigated. Just after mixing, a simultaneous drop of both the hydraulic and the total lateral pressures was recorded, followed by a cancellation of total lateral pressure and a negative value of hydraulic pressure. Compared to other standard methods (Vicat, calorimetry, ultrasonic pulse-echo, etc …), the device was able to give simple and direct information about the mechanical state of the material, in situ. The kinetic variation of the hydraulic pressure occurring during the plastic phase of cement pastes using two portland cement fractions and a limestone filler was investigated. To relate the hydraulic pressure measurements with workability, a study on the evolution of the rheology of the cement paste was conducted. The experiments on standard concretes, which had the same free water content as an equivalent cement paste, show a similar hydraulic pressure variation as long as the pressure is positive. This is not the case for SCC where the observed hydraulic pressure variation is slower and the time of zero pressure is delayed compared to the equivalent cement paste. The presence of limestone and the HRWRA is the main reason for this retardation effect. In addition, as soon as the pressure becomes negative, due to the presence of aggregates, a delaying effect on the pressure variation was observed. In the end, field test show that the hydraulic pressure device could be used to monitor the field schedule of successive pouring, setting and demolding.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122071141","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 describes an experimental investigation that was carried out in order to evaluate the effects of high range water reducing admixture (HRWRA), viscosity-enhancing admixture (VEA), and binder type on key workability characteristics of self-consolidating concrete (SCC), including retention of deformability, passing ability, and stability. Concrete-equivalent mortar (CEM) mixtures were prepared to evaluate the effect of admixture-binder combinations on flow characteristics, including minimum water content (MWC) to initiate flow and relative water demand (RWD) to increase a given fluidity. Four polycarboxylate-based HRWRAs, a polynaphthalene sulfonate-based HRWRA, four types of VEAs, and three blended cements were evaluated. In total, 16 SCC mixtures with initial slump flow consistency of 660 +/- 20 mm and air volume of 6.5 +/- 1.5%, and 17 CEM mixtures were investigated. Flow characteristics of SCC and CEM mixtures made with a number of admixture-binder combinations indicate that the efficiency of admixture-binder combination depends on water-to-cementitious material ratio (w/cm), type of binder, and type of admixtures. The CEM approach can be used to evaluate the effect of admixture-binder combination on flow characteristics because the increase in MWC to initiate flow of CEM corresponds to higher demand in HRWRA in SCC mixtures. Binder type was shown to have marked influence on the retention of slump flow, L-box and V-funnel passing ability, filling capacity, and surface settlement characteristics. The binder type also affects HRWRA and air-entraining admixture (AEA) demand. As established from CEMs, B3 quaternary cement with the smallest 50% passing diameter had the highest MWC (lowest packing density) needed to initiate flow and the highest RWD (highest robustness to changes in water). SCCs made with such quaternary cement and polycarboxylate-based HRWRA also exhibited the highest HRWRA demand compared those prepared with other blended cements. Both sets of SCCs made with 0.35 w/cm and 0.42 w/cm plus VEA had similar HRWRA demand and static stability when the polycarboxylate-based HRWRA was used.
{"title":"Effect of Various Admixture-Binder Combinations on Workability of Ready-Mix Self-Consolidating Concrete","authors":"S. Hwang, K. Khayat","doi":"10.14359/15821","DOIUrl":"https://doi.org/10.14359/15821","url":null,"abstract":"This paper describes an experimental investigation that was carried out in order to evaluate the effects of high range water reducing admixture (HRWRA), viscosity-enhancing admixture (VEA), and binder type on key workability characteristics of self-consolidating concrete (SCC), including retention of deformability, passing ability, and stability. Concrete-equivalent mortar (CEM) mixtures were prepared to evaluate the effect of admixture-binder combinations on flow characteristics, including minimum water content (MWC) to initiate flow and relative water demand (RWD) to increase a given fluidity. Four polycarboxylate-based HRWRAs, a polynaphthalene sulfonate-based HRWRA, four types of VEAs, and three blended cements were evaluated. In total, 16 SCC mixtures with initial slump flow consistency of 660 +/- 20 mm and air volume of 6.5 +/- 1.5%, and 17 CEM mixtures were investigated. Flow characteristics of SCC and CEM mixtures made with a number of admixture-binder combinations indicate that the efficiency of admixture-binder combination depends on water-to-cementitious material ratio (w/cm), type of binder, and type of admixtures. The CEM approach can be used to evaluate the effect of admixture-binder combination on flow characteristics because the increase in MWC to initiate flow of CEM corresponds to higher demand in HRWRA in SCC mixtures. Binder type was shown to have marked influence on the retention of slump flow, L-box and V-funnel passing ability, filling capacity, and surface settlement characteristics. The binder type also affects HRWRA and air-entraining admixture (AEA) demand. As established from CEMs, B3 quaternary cement with the smallest 50% passing diameter had the highest MWC (lowest packing density) needed to initiate flow and the highest RWD (highest robustness to changes in water). SCCs made with such quaternary cement and polycarboxylate-based HRWRA also exhibited the highest HRWRA demand compared those prepared with other blended cements. Both sets of SCCs made with 0.35 w/cm and 0.42 w/cm plus VEA had similar HRWRA demand and static stability when the polycarboxylate-based HRWRA was used.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123913630","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":"Workability and Earthquake Resistance Behavior of Self-Compacting Concrete Frame","authors":"P. Huang","doi":"10.14359/15842","DOIUrl":"https://doi.org/10.14359/15842","url":null,"abstract":"","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114996447","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 Different Mineral Powders on Properties of Fresh and Hardened Self-Consolidating Concrete","authors":"C. Shi","doi":"10.14359/15834","DOIUrl":"https://doi.org/10.14359/15834","url":null,"abstract":"","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134068832","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 examines the effect of aggregate content and gradation on self consolidating concrete (SCC) passing ability. Passing ability is defined as an SCC mixture’s ability to flow through narrow spaces without segregating or blocking. The mixtures tested ranged over two uniform aggregate sizes, two aggregate contents, two different mixture design philosophies, and a gradated aggregate mixture. Passing ability tests, slump flow tests, horizontal flow tests, and stereology tests were performed on these mixtures. Stereology is a statistical counting technique used primarily by natural scientists and concrete researchers have used sterolog to describe bubble size and distribution in concrete. A vertical flow box was developed by McBride to determine the passing ability of the various mixtures. Various bar spacings are tested. From the results of this study, it seems that two stereology parameters can be correlated to the minimum bar spacing that will allow SCC to pass. These parameters are the ratio of maximum aggregate size to mean aggregate free distance and the ratio of maximum aggregate size to mean aggregate random spacing.
{"title":"Coarse Aggregate and Self-Consolidating Concrete Passing Ability","authors":"J. McBride, D. Mukai","doi":"10.14359/15835","DOIUrl":"https://doi.org/10.14359/15835","url":null,"abstract":"This paper examines the effect of aggregate content and gradation on self consolidating concrete (SCC) passing ability. Passing ability is defined as an SCC mixture’s ability to flow through narrow spaces without segregating or blocking. The mixtures tested ranged over two uniform aggregate sizes, two aggregate contents, two different mixture design philosophies, and a gradated aggregate mixture. Passing ability tests, slump flow tests, horizontal flow tests, and stereology tests were performed on these mixtures. Stereology is a statistical counting technique used primarily by natural scientists and concrete researchers have used sterolog to describe bubble size and distribution in concrete. A vertical flow box was developed by McBride to determine the passing ability of the various mixtures. Various bar spacings are tested. From the results of this study, it seems that two stereology parameters can be correlated to the minimum bar spacing that will allow SCC to pass. These parameters are the ratio of maximum aggregate size to mean aggregate free distance and the ratio of maximum aggregate size to mean aggregate random spacing.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128273419","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 describes how the challenge of producing successful self-consolidating concrete (SCC) is based on consistently achieving high flow and high stability. The foundation of high quality SCC production is the suitability of the underlying materials and a mixture design that is optimized for those materials and the application. Not all applications require relatively high slump flows in the range of 28-30 inches (700- 750mm), where control measures need to be especially well managed. Furthermore, even the best mixture designs can have stability limitations. In order to assure that SCC applications proceed with minimal difficulties, the concrete producer must anticipate variations in materials and production operations by using effective quality control procedures. Changes in cement reactivity, aggregate properties (gradation, shape, and water demand), free moisture, and extra sources of moisture that may be present, for instance, in the truck, and the mixing process need to be carefully monitored. This paper will discuss specific examples that demonstrate best practices in mixture design, QA/QC, and production techniques.
{"title":"Getting it Right: Successful SCC Production Practices","authors":"C. R. Cornman, H. Koyata, A. Jeknavorian","doi":"10.14359/15819","DOIUrl":"https://doi.org/10.14359/15819","url":null,"abstract":"This paper describes how the challenge of producing successful self-consolidating concrete (SCC) is based on consistently achieving high flow and high stability. The foundation of high quality SCC production is the suitability of the underlying materials and a mixture design that is optimized for those materials and the application. Not all applications require relatively high slump flows in the range of 28-30 inches (700- 750mm), where control measures need to be especially well managed. Furthermore, even the best mixture designs can have stability limitations. In order to assure that SCC applications proceed with minimal difficulties, the concrete producer must anticipate variations in materials and production operations by using effective quality control procedures. Changes in cement reactivity, aggregate properties (gradation, shape, and water demand), free moisture, and extra sources of moisture that may be present, for instance, in the truck, and the mixing process need to be carefully monitored. This paper will discuss specific examples that demonstrate best practices in mixture design, QA/QC, and production techniques.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127146220","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 describes how fresh concrete is a complex fluid consisting of a suspension of a high volume of water with high volume percentage of particulate solid that has a very wide particle size distribution. The rheological properties of fresh concrete control the flow behavior of the material in mixing, placement, consolidation and finishing. Test methods that measure flow using a single parameter (e.g. slump) cannot properly evaluate the rheological properties of concrete in all uses. The paper describes how the American Concrete Institute (ACI) committee 236A, with the support of the Concrete Research Council and industry, has tested four concrete rheometers that were specifically designed to evaluate rheological properties of concrete materials. The second test series expands the data from the first test series using the same approach of bringing the rheometers together at a common test site and testing the same concrete mixtures simultaneously. All of the rheometers can measure a flow curve for fresh concretes with slumps in the range from 100 mm to 250 mm or non-segregating concretes with slump flows in the range from 300 mm to 800 mm. Each rheometer evaluates yield stress and plastic viscosity by fitting a Bingham model flow curve to measurements of rotation rate and torque for each mix. All of the rheometers gave different absolute values for the Bingham constants of yield stress and plastic viscosity for each mix. But all of the rheometers ranked the mixes in the same order for both yield stress and plastic viscosity.
{"title":"Comparison of Concrete Rheometers","authors":"L. Brower, C. Ferraris","doi":"10.14359/15838","DOIUrl":"https://doi.org/10.14359/15838","url":null,"abstract":"This paper describes how fresh concrete is a complex fluid consisting of a suspension of a high volume of water with high volume percentage of particulate solid that has a very wide particle size distribution. The rheological properties of fresh concrete control the flow behavior of the material in mixing, placement, consolidation and finishing. Test methods that measure flow using a single parameter (e.g. slump) cannot properly evaluate the rheological properties of concrete in all uses. The paper describes how the American Concrete Institute (ACI) committee 236A, with the support of the Concrete Research Council and industry, has tested four concrete rheometers that were specifically designed to evaluate rheological properties of concrete materials. The second test series expands the data from the first test series using the same approach of bringing the rheometers together at a common test site and testing the same concrete mixtures simultaneously. All of the rheometers can measure a flow curve for fresh concretes with slumps in the range from 100 mm to 250 mm or non-segregating concretes with slump flows in the range from 300 mm to 800 mm. Each rheometer evaluates yield stress and plastic viscosity by fitting a Bingham model flow curve to measurements of rotation rate and torque for each mix. All of the rheometers gave different absolute values for the Bingham constants of yield stress and plastic viscosity for each mix. But all of the rheometers ranked the mixes in the same order for both yield stress and plastic viscosity.","PeriodicalId":120168,"journal":{"name":"SP-233: Workability of SCC: Roles of Its Constituents and Measurement Techniques","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122661299","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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