"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete"最新文献

{"title":"The Chemical Shrinkage of Pozzolanic Reaction Products","authors":"H. Justnes, B. Ardoullie, E. Hendrix, E. J. Sellevold, D. Gemert","doi":"10.14359/5979","DOIUrl":"https://doi.org/10.14359/5979","url":null,"abstract":"The total chemical shrinkage of silica fume and Class F fly ash, both as pozzolanic materials reacting with lime and as mineral additives replacing portland cement, was studied. By increasing pH, the rate related to the pozzolanic reaction decreased for silica fume and increased for fly ash. Although the presence of alkalis are catalytically necessary for a rapid pozzolanic reaction of silica fume, the pH increase reduces the solubility of calcium hydroxide (CH) due to the common ion effect. This may explain why the reaction rate decreases if dissolution of CH, followed by precipitation of CSH, is the rate-limiting step. The increased reactivity of fly ash, caused by a pH increase, indicates that the dissolution of the glassy aluminosilicate phase by alkalis was determining the overall rate of the process. The total chemical shrinkage was crudely estimated to be 8.8 ml/100 g of reacted silica fume and 10.0 ml/100 g of reacted fly ash, as compared with 6.3 ml/100 g of portland cement. The measured shrinkage for silica fume could be higher than the above value since minor amounts of silicon metal in the silica fume could produce an expansion due to evolved hydrogen gas.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123888333","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":"The Repair of High-Strength Silica Fume Concrete-A Case History","authors":"G. Hoff, R. Elimov","doi":"10.14359/6000","DOIUrl":"https://doi.org/10.14359/6000","url":null,"abstract":"This paper describes the repair of a high-strength silica fume concrete structure using a high-strength repair material which also contains silica fume. The repair represented the largest single application of this material and the largest single use of low-pressure spraying of the repair material. Information is provided on the repair procedures, proficiency of the nozzlemen, acceptance criteria applied to this type of operation. Because of the lack of actual in-situ bond and compressive strength data on high strength concrete in the literature, all of the actual in-situ test results are provided for this repair. Approximately 1,300 m to the third power of the repair material was used to repair 24,000 sq. meters of concrete surface damaged during a slipform operation. The damaged concrete had compressive strengths in the range of 78 to 82 MPa. The repair material had a target compressive strength of 80 MPa and an in-situ bond strength requirement (minimum) of 1.5 MPa. Using low-pressure spraying techniques because of confined working areas, the repairs were successfully completed over a 24 week period. Compressive strengths of cores from sprayed production test panels averaged 85 MPa at 28-days. The in-situ bond strength of the repairs did not appear to increase with age and averaged 1.87 MPa for all ages evaluated.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121221783","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":"Effects of Fly Ash and Silica Fume on High Performance Concrete","authors":"S. Nagataki, S. Miyazato, T. Saitoh","doi":"10.14359/5986","DOIUrl":"https://doi.org/10.14359/5986","url":null,"abstract":"These days, large and complicated concrete structures are mushrooming. Performance requirements include not only functionality and strength but also aesthetics. From a material viewpoint, it can be said that the requirements for high performance concrete include: adequate flowability, strength and durability. This study shows that combining fly ash and silica fume as mineral admixture is an effective way to improve the properties of concrete. The influence of fly ash and silica fume on fluidity and strength of mortar and concrete was experimentally investigated. Five fly ashes, classified into 3 types obtaining from each hopper of precipitator, were used and constituted 60, 70, 80 and 100% by weight of the total amount of mineral admixture. In this study, flowability was investigated by measuring the flow/slump flow while keeping the chemical admixture-binder ratio within a pre-determined range. Strength was evaluated by compressive strength tests at 14,28 and 91 days. The relationship between mineral admixture properties and mortar/concrete properties were studied. As a result of the tests, higher strength and adequate flowability were obtained by combining fly ash and silica fume.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121503583","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":"Soil Stabilization using Lime-Activated Ground Granulated Blast Furnace Slag","authors":"D. Higgins, J. Kinuthia, S. Wild","doi":"10.14359/6023","DOIUrl":"https://doi.org/10.14359/6023","url":null,"abstract":"Soil stabilization with cement or lime is a well established technique for use in highway or foundation construction. Extensive laboratory investigations and a full-scale trial have been carried out to evaluate the performance of ground granulated blast furnace slag (ggbs) in combination with lime, for stabilizing soils. This paper reports the results of laboratory tests for strength and swelling, and also describes the full-scale trial. The applicability of lime/ggbs combinations has been demonstrated. In addition, laboratory tests have shown a previously undemonstrated advantage where the incorporation of ggbs combats the deleterious swelling which can occur when sulphate-containing soils are stabilized with cement or lime.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117224076","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":"Influence of Unburnt Carbon in the Performance of Concrete Mixtures","authors":"L. Coppola, R. Troli, P. Zaffaroni, G. Belz, M. Collepardi","doi":"10.14359/5983","DOIUrl":"https://doi.org/10.14359/5983","url":null,"abstract":"In many standard specifications there is a limit for the maximum amount of unburnt carbon of fly ashes aften referred to as LOI. In particular, according to the European norm EN 450, this limit is 5% on the continental basis of the European Unity, or 7% on the domestic national basis. Therefore, fly ashes with LOI over 7% should be rejected as a supplementary cementitious material in concrete mixtures. Four fly ashes from coal-fired electric generating plants, with LOI content of about 4,7,9,and 11%, were used to manufacture concrete mixtures. They had the water-cement (w/c) ratio of 0.68, corresponding to a water-binder ratio of 0.48 and a fly ash/binder ratio of 0.30. A small amount of superpasticizer (0.3-0.4% by cement mass) was required to compensate the slump decrease caused by fly ash with higher LOI (>=7%). Two reference concrete mixtures, without fly ash, were also produced with a w/c of 0.68 and 0.48. The performance of all these concrete mixtures was assessed in terms of compressive strength at early and later ages (1-180 days), water permeability, chloride diffusion, and carbonation rate. There was no evidence available which indicated that the LOI content of the fly ash affected negatively any of the properties studied. In particular, due perhaps to its peculiar pozzolanic activity, the fly ash with the highest LOI content (11.30%) performed better than that with the smallest amount of LOI material (4.19%). This occurred in terms of higher compressive strength, lower water-permeability, slower chloride diffusion, and decreased carbonation rate in the corresponding concretes. Therefore, the conformity criteria adopted by some standard specifications in rejecting fly ashes only on the basis of the relatively high LOI content, without determining the corresponding concrete performance in terms of strength and durability, appear to be technologically inadequate.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124032105","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":"Performance of a Different Pozzolanic Cement Concretes Under Cyclic Wetting and Drying","authors":"A. Ramezanianpour, Radfar, Hadikhanloo, Moslehi, Maghsoodi","doi":"10.14359/6007","DOIUrl":"https://doi.org/10.14359/6007","url":null,"abstract":"As part of a comprehensive research project on the durability of on and offshore concrete structures in the Persian Gulf, a simulation laboratory has been made use of. The present study consists mainly of nine month exposure tests in the tidal and atmospheric zone conditions in the laboratory. Concrete specimens containing different supplementary materials, namely silica fume, blast-furnace slag, diatomous earth and trass, have been thoroughly investigated. The tests conducted include compressive strength, volume changes, half cell potentials, carbonation, and chloride diffusion, all at different ages. With respect to the alternate cycles of wetting and drying, the superior performance of silica fume was followed by the diatomous earth pozzolan. However, all concrete mixtures containing natural and artificial pozzolans showed better performance when compared with the plain portland cement control concrete mixtures.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116309130","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":"Durability Study of Mount Pinatubo Ejecta Concrete Paving Blocks","authors":"J. Agron","doi":"10.14359/5984","DOIUrl":"https://doi.org/10.14359/5984","url":null,"abstract":"Coincident with the investigation of the utilization of Mount Pinatubo ejecta on the production of paving blocks for sidewalks, parking areas and other footpaths, a study on the durability of the blocks was also undertaken. Blocks with a plan area of 100mm x 200mm and a thickness of 85mm were prepared with three mixture proportions. The mixture proportions were prepared to represent three strength levels. Specimens from each mixture were subjected to both natural and accelerated weathering conditions. The compressive strength in accordance with ASTM C 936 and the abrasion resistance in accordance with ASTM C 779 were determined for various ages. The test results as shown in this paper for the durability parameters selected, show favorable long term properties of the paving blocks.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130310356","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":"Comparative Study on Mortar Containing Fly Ash from Southeast Asia and Japan in Relation to Strength and Durability","authors":"K. Wangwichit, M. Hisada, N. Otsuki, S. Nagataki","doi":"10.14359/5974","DOIUrl":"https://doi.org/10.14359/5974","url":null,"abstract":"In Thailand, the utilization of fly ash as a concrete admixture has been increasing gradually. However, there are no local standards regulating the use of fly ash. Mixing of concrete usually follows standards that contain requirements, especially temperature, that are difficult or sometimes impossible to satisfy. Therefore, this research was carried out to verify the influence of temperature, hot (Thailand) and temperate (Japan) climate, on the strength and durability properties of fly ash mortar. Also, to propose an optimum range of cement replacement percentage and water-binder ratio for each kind of fly ash under Thai (simulated) and Japanese climate conditions. From this investigation, it was found that fly ash exhibited advantages in strength and durability of mortar under high temperatures. The strength activity index of both fly ash mortars were satisfied in accordance with ASTM C 618 under all temperatures considered. Furthermore, the optimum range of cement replacement and water-binder ratio became wider with increasing temperature. Thus, fly ash is recommended to be used under high temperatures.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121075065","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":"Mechanical Properties and Durability of Concrete Made with High Volume Fly Ash Blended Cements","authors":"N. Bouzoubaâ, Min-hong Zhang, A. Bilodeau, V. Malhotra","doi":"10.14359/5999","DOIUrl":"https://doi.org/10.14359/5999","url":null,"abstract":"This paper describes the development of high-volume fly ash (HVFA) blended cements. The blended cements were made by combined grinding 45% of ASTM Type III cement clinker, 55% of ASTM class F fly ash, a small percentage of gypsum, and 0.7% of superplasticizer by weight of the cement including clinker, fly ash, and gypsum. Several concrete mixtures were made with the control and the blended cements; also, concrete mixtures were made in which high volumes of fly ash had been added at the concrete mixer. A large number of test specimens were cast for determining the mechanical properties and durability characteristics of the hardened concrete. The results of the investigations indicated that the mechanical properties of concrete made with the HVFA blended cement are superior to that made with laboratory-produced portland cement and where the fly ash had been added as a separately batched material at the mixer. The durability characteristics of these two concretes are comparable except that the de-icing salt-scaling resistance of concrete made with the HVFA blended cement is considerably inferior to that of the concrete in which fly ash had been added as a separately-batched material at the mixer. The coarse Genesee fly ash that fails to meet the fineness requirements of ASTM C 618 has been used successfully to produce a HVFA blended cement. The mechanical and durability properties of concrete made with this blended cement (BCGS), are comparable to the concrete made with the HVFA blended cement produced with the finer Sundance fly ash. Thus, the production of HVFA blended cements offers a possible way for the utilization of coarse fly ashes. The intergrinding of the dry superplasticizer with clinker, fly ash and gypsum to produce HVFA blended cements did not pose any problems; however, for equal performance as regards to slumps, the amount of the superplasticizer needed in the blended cements was higher compared to that needed when superplasticizer was added separately at the mixer.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128667951","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":"Influence of Palm Oil Fuel Ash on Sulfate Resistance of Mortar and Concrete","authors":"M. Hussin, A. Awal","doi":"10.14359/5992","DOIUrl":"https://doi.org/10.14359/5992","url":null,"abstract":"Pozzolanic materials, either natural or artificial, have long demonstrated their effectiveness in producing high-performance concrete. Artificial pozzolans, such as fly ash and rice husk ash have gained acceptance as supplementary cementing materials in many parts of the world. Perhaps the latest addition to the pozzolanic ash family is palm oil fuel ash, a waste material obtained on burning of palm oil husk and shell in the palm oil milling industry. This paper presents laboratory test results on the performance of palm oil fuel ash (POFA) in mortar and concrete containing the ash as a partial replacement of normal portland cement against sulfate attack. Mortar bars having dimensions of 25 x 25 x 250 mm, and 100 mm concrete cube specimens were cast with a fixed water-cementitious material ratio of 0.5 where normal portland cement was replaced by 30% POFA by mass. After 28 days of moist curing, the specimens were put into 10% sodium sulfate solution with alternate wetting and drying cycles. During the test period of over one year, the mortar bar specimens were periodically subjected to expansion measurements while the concrete cube specimens were tested for change in mass. Finally, examination of the deteriorated materials through X-ray diffraction analysis was carried out to elucidate the mechanism of deterioration. It has been observed that the specimens with POFA, in general, exhibited significantly higher resistance to the sulfate attack than those prepared with normal portland cement alone.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121857325","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}