{"title":"Factor Ten Emmisions Reductions : The Key To Sustainable Development and Economic Prosperity for Cement","authors":"R. Horton","doi":"10.14359/10770","DOIUrl":"https://doi.org/10.14359/10770","url":null,"abstract":"","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129242251","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}
E. Irassar, V. Bonavetti, H. D. G. Menhdez, Cabrera
European countries have a great deal of experience in the use of Portland Limestone Cements (PLC). In Latin America, most of the cement plants use limestone as a raw material and an increase in cement production is expected in the next few years. The manufacture of this cement would represent a rapid increase of production without environmental consequences. This paper synthesizes data from a research program carried out over two years to determine the effects of limestone filler on concrete and mortar behavior. At early age, the influence of limestone filler on workability, bleeding, initial curing and mechanical behavior (modulus of elasticity, compressive and tensile strength) was studied. Sulfate resistance and chloride penetration, the most important durability problems related with PLC, were also studied. The addition of slag was also investigated to improve the long-term strength and the durability of PLC. Results show that cements containing around 10% of limestone filler provide similar or better mechanical behavior than portland cement concrete, without compromising their durability properties where low chloride diffusion and high sulfate resistance is required. In this case, the environmental impact of cement manufacture decreases because the energy consumption and the carbon dioxide emission are reduced per ton of cement and the combination with supplementary cementing materials (slag, fly ash or natural pozzolan) can improve these aspects.
{"title":"Mechanical Properties and Durability of Concrete Made With Portland Limestone Cement","authors":"E. Irassar, V. Bonavetti, H. D. G. Menhdez, Cabrera","doi":"10.14359/10798","DOIUrl":"https://doi.org/10.14359/10798","url":null,"abstract":"European countries have a great deal of experience in the use of Portland Limestone Cements (PLC). In Latin America, most of the cement plants use limestone as a raw material and an increase in cement production is expected in the next few years. The manufacture of this cement would represent a rapid increase of production without environmental consequences. This paper synthesizes data from a research program carried out over two years to determine the effects of limestone filler on concrete and mortar behavior. At early age, the influence of limestone filler on workability, bleeding, initial curing and mechanical behavior (modulus of elasticity, compressive and tensile strength) was studied. Sulfate resistance and chloride penetration, the most important durability problems related with PLC, were also studied. The addition of slag was also investigated to improve the long-term strength and the durability of PLC. Results show that cements containing around 10% of limestone filler provide similar or better mechanical behavior than portland cement concrete, without compromising their durability properties where low chloride diffusion and high sulfate resistance is required. In this case, the environmental impact of cement manufacture decreases because the energy consumption and the carbon dioxide emission are reduced per ton of cement and the combination with supplementary cementing materials (slag, fly ash or natural pozzolan) can improve these aspects.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"268 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121322119","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 an experimental analysis of recycled concrete (RC) in which the natural aggregates are replaced by recycled concrete aggregates (RCA). This experimental program covers the specifications of the aggregates employed, together with that of the concrete that is manufactured with them. The considerable effect on the permeability of RC that is produced by the use of RCA is described and discussed. Tests reveal considerable increase in permeability of RC in comparison with the reference concrete. Both the water penetration depths and the permeability coefficients are increased in a manner that may be correlated with the increase in the replacement of natural aggregates by RCA. These increments are attributed to the high porosity of RCA.
{"title":"Repercussionson Concrete Permeability Due to Recycled Concrete Aggregate","authors":"J. Gomez, L. Agulló, E. Vázquez","doi":"10.14359/10781","DOIUrl":"https://doi.org/10.14359/10781","url":null,"abstract":"This paper presents an experimental analysis of recycled concrete (RC) in which the natural aggregates are replaced by recycled concrete aggregates (RCA). This experimental program covers the specifications of the aggregates employed, together with that of the concrete that is manufactured with them. The considerable effect on the permeability of RC that is produced by the use of RCA is described and discussed. Tests reveal considerable increase in permeability of RC in comparison with the reference concrete. Both the water penetration depths and the permeability coefficients are increased in a manner that may be correlated with the increase in the replacement of natural aggregates by RCA. These increments are attributed to the high porosity of RCA.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127484045","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 aim of this study is the valorization of magnesium slags in order to recycle them in construction block form. Two kinds of slag with hydraulic properties are obtained according to a 1/3-2/3 ratio: powdered slag similar to cement, and granulated slag similar to sand. A previous laboratory study was carried out in order to obtain sufficient mechanical strength for construction blocks and setting kinetics compatible with an industrial process. The present paper deals with the consecutive implementation of life size tests on an industrial scale. Two pre-industrial tests were carried out in extremely different temperature conditions: 7 degrees C for the first test and 22 degrees C for the second one. Furthermore, the second test benefited from the new casting conditions resulting from updating of the manufacturing unit. The first test showed that the laboratory study permitted to adjust the set kinetics to a level adequate for industrial casting, whereas the mechanical strength obtained was lower than expected when the powdered slag was used as a substitute for cement. The second test enabled the authors to obtain enough mechanical strength for mixtures entirely composed of magnesium slags and proved the possibility of total and simultaneous enhancing value of magnesium slags as construction blocks. More generally, these industrial tests show how difficult the transfer to the industrial scale is.
{"title":"Pre-Industrial Manufacturing Tests on Construction Blocks Composed of Magnesium Slags","authors":"R. Cabrillac, J. Gallias, M. Courtial, G. Pierson","doi":"10.14359/10799","DOIUrl":"https://doi.org/10.14359/10799","url":null,"abstract":"The aim of this study is the valorization of magnesium slags in order to recycle them in construction block form. Two kinds of slag with hydraulic properties are obtained according to a 1/3-2/3 ratio: powdered slag similar to cement, and granulated slag similar to sand. A previous laboratory study was carried out in order to obtain sufficient mechanical strength for construction blocks and setting kinetics compatible with an industrial process. The present paper deals with the consecutive implementation of life size tests on an industrial scale. Two pre-industrial tests were carried out in extremely different temperature conditions: 7 degrees C for the first test and 22 degrees C for the second one. Furthermore, the second test benefited from the new casting conditions resulting from updating of the manufacturing unit. The first test showed that the laboratory study permitted to adjust the set kinetics to a level adequate for industrial casting, whereas the mechanical strength obtained was lower than expected when the powdered slag was used as a substitute for cement. The second test enabled the authors to obtain enough mechanical strength for mixtures entirely composed of magnesium slags and proved the possibility of total and simultaneous enhancing value of magnesium slags as construction blocks. More generally, these industrial tests show how difficult the transfer to the industrial scale is.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129334814","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 environmental concerns related to the production of cement in terms of the energy consumption and the emission of CO2 lead to the search for more environmentally viable alternatives to cement. One of those alternative materials is alkali-activated slag (AAS) where ground granulated blast furnace slag is used not as a partial replacement to cement but as the sole binder in the production of concrete. The performance of alkali-activated slag concrete with sodium silicate (water glass) as an activator was studied. The scope of the work covered seven mixes: a normal strength OPC control mix, a blended OPC/Slag mix of similar compressive strength but of lower water to binder ratio, a second OPC control mix of a water to binder ratio similar to that of the OPC/Slag mix, and four alkali-activated slag mixes of the same binder content and the same water to binder ratio as those of the second OPC mix. The AAS mixes were prepared with slag as the sole binder, activated with water glass at two dosages, 4% and 6% Na2O (by weight of slag). Two types of water glass were used, one in a solution form and the other in a solid granules form. The two forms of the activator used were also of different silicate modulus (Ms); 1.65 for the solution form and 1.0 for the granule form. Different curing regimes were used including normal water curing, air dry curing and accelerated autoclave heat curing. The fresh concrete properties studied were setting time, workability and air content. The engineering properties studied were compressive strength, splitting tensile strength, flexural strength, dynamic modulus of elasticity and ultrasonic pulse velocity and drying shrinkage. The durability potential of alkali-activated stag concrete was investigated by testing for oxygen permeability, chloride penetration resistance, porosity, carbonation, and alkali-silica reaction. The hydration of alkali-activated slag was studied using x-ray diffraction and thermogravimetry techniques. Alkali-activated slag concrete was found to achieve good workability which was, comparable to that of OPC and OPCfslag concrete. The increase of the Na2O dosage resulted in a lower workability and the activator with higher silicate modulus exhibited lower workability. AAS concrete however, sets rapidly if not controlled by the addition of lime. The main hydration products in the AAS systems were C-S-H (I) and hydrotalcite as observed in the XRD patterns with autoclaving resulting in the formation of a more crystalline C-S-H gel and the possible formation of xonotlite. The mechanical properties of AAS concrete are highly influenced by the activator's silicate modulus and the Na2O dosage where strength was found to be higher with the higher modulus and dosage. The AAS concrete is very sensitive to curing and dry curing resulted in a reduction in strength for AAS concrete much more than that for OPC concrete. Accelerated curing (autoclave) increased the initial gain of strength in AAS concrete but even
{"title":"Performance of Alkali -Activated Slag Concrete","authors":"S. Al-Otaibi, C. J. Lynsdale, J. Sharp","doi":"10.14359/10800","DOIUrl":"https://doi.org/10.14359/10800","url":null,"abstract":"The environmental concerns related to the production of cement in terms of the energy consumption and the emission of CO2 lead to the search for more environmentally viable alternatives to cement. One of those alternative materials is alkali-activated slag (AAS) where ground granulated blast furnace slag is used not as a partial replacement to cement but as the sole binder in the production of concrete. The performance of alkali-activated slag concrete with sodium silicate (water glass) as an activator was studied. The scope of the work covered seven mixes: a normal strength OPC control mix, a blended OPC/Slag mix of similar compressive strength but of lower water to binder ratio, a second OPC control mix of a water to binder ratio similar to that of the OPC/Slag mix, and four alkali-activated slag mixes of the same binder content and the same water to binder ratio as those of the second OPC mix. The AAS mixes were prepared with slag as the sole binder, activated with water glass at two dosages, 4% and 6% Na2O (by weight of slag). Two types of water glass were used, one in a solution form and the other in a solid granules form. The two forms of the activator used were also of different silicate modulus (Ms); 1.65 for the solution form and 1.0 for the granule form. Different curing regimes were used including normal water curing, air dry curing and accelerated autoclave heat curing. The fresh concrete properties studied were setting time, workability and air content. The engineering properties studied were compressive strength, splitting tensile strength, flexural strength, dynamic modulus of elasticity and ultrasonic pulse velocity and drying shrinkage. The durability potential of alkali-activated stag concrete was investigated by testing for oxygen permeability, chloride penetration resistance, porosity, carbonation, and alkali-silica reaction. The hydration of alkali-activated slag was studied using x-ray diffraction and thermogravimetry techniques. Alkali-activated slag concrete was found to achieve good workability which was, comparable to that of OPC and OPCfslag concrete. The increase of the Na2O dosage resulted in a lower workability and the activator with higher silicate modulus exhibited lower workability. AAS concrete however, sets rapidly if not controlled by the addition of lime. The main hydration products in the AAS systems were C-S-H (I) and hydrotalcite as observed in the XRD patterns with autoclaving resulting in the formation of a more crystalline C-S-H gel and the possible formation of xonotlite. The mechanical properties of AAS concrete are highly influenced by the activator's silicate modulus and the Na2O dosage where strength was found to be higher with the higher modulus and dosage. The AAS concrete is very sensitive to curing and dry curing resulted in a reduction in strength for AAS concrete much more than that for OPC concrete. Accelerated curing (autoclave) increased the initial gain of strength in AAS concrete but even","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"12 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120974462","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":"Microstructure of Concrete from a Crack-Free Structure Designed to Last a Thousand Years","authors":"J. Asselanis, P. Mehta","doi":"10.14359/10793","DOIUrl":"https://doi.org/10.14359/10793","url":null,"abstract":"","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121238859","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}
In the production of iron and steel, two different types of slags are generated - one, the blast-furnace slag obtained at the time of iron extraction and the other, the steel slag generated during the conversion of iron to steel in the steel melting shop. The blast-furnace slag, after proper granulation, is used extensively as a supplementary cementitious material in the cement and concrete industry. The steel slag, however, has not found much use and is mostly dumped as a waste material after removing scrap steel. In order to explore the avenues for economical utilization of this slag in cement-making, an extensive literature and patent survey has been carried out. Further, based on the steel slags available from some of the integrated steel plants in India, the material has been characterized in detail and its hydraulic behavior has been studied. Studies relating to the potential use of this slag as a raw material in the production of portland cement clinker as well as in the manufacture of special cements like the calcium suphoaluminoferrite type have been experimentally carried out at a pilot scale. Blended cement formulations with maximized incorporation of steel slag have been prepared and studied. Based on available literature and experimental findings, an attempt has been made to look at the potential scenario of steel slag usage in cement-making with specific emphasis on environmental amelioration and greenhouse gas reduction.
{"title":"Steel Slags in Cement-Making-The Current Status of Development","authors":"A. Chatterjee","doi":"10.14359/10773","DOIUrl":"https://doi.org/10.14359/10773","url":null,"abstract":"In the production of iron and steel, two different types of slags are generated - one, the blast-furnace slag obtained at the time of iron extraction and the other, the steel slag generated during the conversion of iron to steel in the steel melting shop. The blast-furnace slag, after proper granulation, is used extensively as a supplementary cementitious material in the cement and concrete industry. The steel slag, however, has not found much use and is mostly dumped as a waste material after removing scrap steel. In order to explore the avenues for economical utilization of this slag in cement-making, an extensive literature and patent survey has been carried out. Further, based on the steel slags available from some of the integrated steel plants in India, the material has been characterized in detail and its hydraulic behavior has been studied. Studies relating to the potential use of this slag as a raw material in the production of portland cement clinker as well as in the manufacture of special cements like the calcium suphoaluminoferrite type have been experimentally carried out at a pilot scale. Blended cement formulations with maximized incorporation of steel slag have been prepared and studied. Based on available literature and experimental findings, an attempt has been made to look at the potential scenario of steel slag usage in cement-making with specific emphasis on environmental amelioration and greenhouse gas reduction.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116704430","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}
In 1995 the German cement industry committed itself to a 20% reduction in its specific fuel energy consumption between 1987 and 2005. In 2000, this commitment has been adapted to the international agreements, particularly to the Kyoto Protocol. Now the voluntary agreement includes a reduction of the specific energy-related carbon dioxide emissions from 1990 to 2008/12 by 28%. As the burning and grinding facilities have been widely optimized during the past years, the German cement industry is planning to increase the substitution of fossil fuels by waste fuels and to promote the marketing of blended cements. From 1987 to 1999 the German cement industry's efforts have led to a reduction of the energy related carbon dioxide emissions by 3.6 million tons per year. The share of waste fuels has been increased from 4 to 23% and the clinker portion in cement has been decreased from 86 to 80.6% by using more granulated blast-furnace slag and unburned limestone as the main constituents in cement. To what extent other instrument like emission trading, joint implementation or clean development mechanism can be used in the future to achieve further reductions, will depend on mutual arrangements and implementation by the international community.
{"title":"German Cement Industry’s Voluntary Efforts on the Issue of Climate Change-A Success Story","authors":"V. Hoenig, M. Schneider","doi":"10.14359/10771","DOIUrl":"https://doi.org/10.14359/10771","url":null,"abstract":"In 1995 the German cement industry committed itself to a 20% reduction in its specific fuel energy consumption between 1987 and 2005. In 2000, this commitment has been adapted to the international agreements, particularly to the Kyoto Protocol. Now the voluntary agreement includes a reduction of the specific energy-related carbon dioxide emissions from 1990 to 2008/12 by 28%. As the burning and grinding facilities have been widely optimized during the past years, the German cement industry is planning to increase the substitution of fossil fuels by waste fuels and to promote the marketing of blended cements. From 1987 to 1999 the German cement industry's efforts have led to a reduction of the energy related carbon dioxide emissions by 3.6 million tons per year. The share of waste fuels has been increased from 4 to 23% and the clinker portion in cement has been decreased from 86 to 80.6% by using more granulated blast-furnace slag and unburned limestone as the main constituents in cement. To what extent other instrument like emission trading, joint implementation or clean development mechanism can be used in the future to achieve further reductions, will depend on mutual arrangements and implementation by the international community.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127607520","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}
On the background of the need for reuse of building rubble and the saving of natural resources, a European Union research project was performed covering concrete technology and durability aspects. A very special precondition was the use of large-scale processed building rubble with unknown origin and the total replacement of aggregates above 2 mm. Comprehensive tests were carried out on the properties of the starting material from different processing plants and fresh concrete, particularly the interdependence of water addition and workability. Investigations on hardened concrete properties included strength development, creep and shrinkage, modulus of elasticity, capillary absorption, freezing and thawing resistance, and carbonation behavior over a long period. The results demonstrate that the industrial production of a high-grade, durable concrete is possible. The project is a promising contribution for sustainable development.
{"title":"Performance of High-Grade Concrete with Full Substitution of Aggregates by Recycled Concrete","authors":"U. Meinhold, G. Mellmann, M. Maultzsch","doi":"10.14359/10775","DOIUrl":"https://doi.org/10.14359/10775","url":null,"abstract":"On the background of the need for reuse of building rubble and the saving of natural resources, a European Union research project was performed covering concrete technology and durability aspects. A very special precondition was the use of large-scale processed building rubble with unknown origin and the total replacement of aggregates above 2 mm. Comprehensive tests were carried out on the properties of the starting material from different processing plants and fresh concrete, particularly the interdependence of water addition and workability. Investigations on hardened concrete properties included strength development, creep and shrinkage, modulus of elasticity, capillary absorption, freezing and thawing resistance, and carbonation behavior over a long period. The results demonstrate that the industrial production of a high-grade, durable concrete is possible. The project is a promising contribution for sustainable development.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133371439","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 series of roller-compacted concrete mixtures were developed for the Norwegian Skjerka hydropower project. The mixture optimization was based on the medium paste concept of the international Committee on Large Dams (ICOLD) using crushed aggregate from the dam site. The mixture optimization consists of a two-step procedure minimizing the paste content, keeping the compacted density about 97.5% of the theoretical air-free density, and giving an optimal loaded Vebe time of 10 - 20 seconds. Nine mixtures were produced using low calcium fly ash and portland cement with various fly ash-cement proportions. The water-binder ratio was kept constant at 0.53 according to the Norwegian code for mass concrete for dams. The laboratory test results showed that 8 of 9 binder combinations produced RCC within the design criteria. The compressive strength development of the water-cured specimens was impressive despite the rather low cement contents, giving 1 year strengths of 2 times the 28-day strengths. The use of high-volume fly ash concrete for RCC dams is one example of concrete in harmony with lower environmental impact and less use of resources.
{"title":"High Volume Fly Ash RCC for Dams/Mixture Optimization and Mechanical Properties","authors":"O. Lahus, S. Jacobsen","doi":"10.14359/10792","DOIUrl":"https://doi.org/10.14359/10792","url":null,"abstract":"A series of roller-compacted concrete mixtures were developed for the Norwegian Skjerka hydropower project. The mixture optimization was based on the medium paste concept of the international Committee on Large Dams (ICOLD) using crushed aggregate from the dam site. The mixture optimization consists of a two-step procedure minimizing the paste content, keeping the compacted density about 97.5% of the theoretical air-free density, and giving an optimal loaded Vebe time of 10 - 20 seconds. Nine mixtures were produced using low calcium fly ash and portland cement with various fly ash-cement proportions. The water-binder ratio was kept constant at 0.53 according to the Norwegian code for mass concrete for dams. The laboratory test results showed that 8 of 9 binder combinations produced RCC within the design criteria. The compressive strength development of the water-cured specimens was impressive despite the rather low cement contents, giving 1 year strengths of 2 times the 28-day strengths. The use of high-volume fly ash concrete for RCC dams is one example of concrete in harmony with lower environmental impact and less use of resources.","PeriodicalId":106585,"journal":{"name":"SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133906077","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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