Academic literature on the topic 'Mineral Admixture'
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Journal articles on the topic "Mineral Admixture"
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Zhao, Mei Li. "The Effects of Mineral Admixture on the Compressive Strength of Concrete." Advanced Materials Research 450-451 (January 2012): 263–66. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.263.
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Mineral admixture was one or more industrial waste, or mixed with finely ground natural minerals, or grinded mixture.By replacing part of the cement with mineral admixtures , cement could be saved and improved the performance of concrete. In this paper，the compressive strength and slump of the concrete with mineral admixture were tested. The amount of cement replaced by mineral admixture in the concrete affected the compressive strength and the slump. According to the compressive strength and slump of the concrete, the optimum dosage of the mineral admixture was from 30% to 40%.
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M M, Kosukhin, Starostina I V, and Kosukhin A M. "The research of clinker monominerals modified suspensions’ rheological properties." International Journal of Engineering & Technology 7, no. 2.23 (2018): 31. http://dx.doi.org/10.14419/ijet.v7i2.23.11878.
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The findings of studying the influence of the superplasticizers of various natures on rheological properties of clinker monominerals’ water suspensions have been presented. It has been shown that the plasticizing activity of admixtures is determined by the nature and the specific surface of a monomineral and the nature of the admixture’s hydrophilic groups, and for complex admixtures also with the ratio of individual components. The optimal admixture dosages for monomineral suspensions of clinker minerals change in the row C2S, C3S, C3A, C4AF, which allows forecasting the influence of admixtures on rheological properties of systems with cements of various mineral compositions. The obtained data correlate with the research findings of the admixtures’ influence on cements of various mineral composition, which allows deducing the influence of admixtures on the systems with other cements, and providing the economically and technologically feasible selection and consumption of admixtures depending on the type of cement and its mineral composition.
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Wang, Yuan Gang, Peng Ma, Kai Jian Huang, Gao Qin Zhang, and Ya Feng Hu. "Impact of Composite Mineral Admixture on Carbonization Resistance of High Performance Concrete." Advanced Materials Research 1095 (March 2015): 248–53. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.248.
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Fly ash, silica fume and ground steel slag are chosen to make up composite mineral admixtures. Through the orthogonal test, carbonization resistance property of High Performance Concrete (HPC) mixed with composite mineral admixtures is studied. Test results show that the carbonization resistance property of HPC can be improved with defined amount of composite mineral admixture mixed, in addition, the effect of ternary composite admixture of ground steel slag, fly ash and silica fume is more obvious than that of binary composite admixture.
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Al-obaidey, Shubbar Jawad. "The Synergic Effects of Mineral Admixtures in Ternary Blended Cement: A Review." Journal of Engineering 27, no. 2 (2021): 83–105. http://dx.doi.org/10.31026/j.eng.2021.02.07.
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In the last decades, using mineral admixture in concrete became very necessary to improve concrete properties and reduce CO2 emissions associated with the cement production process. Subsequently, more sustainable concrete can be obtained. Ternary blended cement containing two different types of mineral admixture can achieve ambitious steps in this trend. In this research, the synergic effects of mineral admixtures in ternary blended cement and its effects on concrete fresh properties, strength, durability, and efficiency factors of mineral admixture in ternary blended cement, were reviewed. The main conclusion reached after reviewing many literature pieces is that the concrete with ternary blended cement, depending on types of mineral admixtures used, replacement percentages by weight of cement, and age of concrete, exhibited superior properties than with no mineral admixtures and corresponding binary blended cement concrete.
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Li, Xin, Qiang Wang, and Shu Hua Liu. "Activity Index of Steel Slag-GGBS Composite Mineral Admixture at Different W/B Ratios." Applied Mechanics and Materials 584-586 (July 2014): 1541–44. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1541.
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The activity index of steel slag-GGBS composite mineral admixture with different steel slag contents at the W/B of 0.3, 0.4, and 0.5 was investigated. The results show that the activity index of the composite mineral admixture with higher GGBS content is larger, and this phenomenon is more obvious at later ages. At lower W/B, the gap of activity index of different composite mineral admixtures is smaller. The activity index of each composite mineral admixture is higher at lower W/B and at later age. The steel slag-GGBS composite mineral admixture is more suitable to be used in high strength concrete than in low strength concrete. As far as the long-term properties of concrete are concerned, the activity index of the composite mineral admixture at the late age should be adopted.
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Popek, Mateusz, and Łukasz Sadowski. "Effect of Selected Mineral Admixtures on Mechanical Properties of Concrete." Key Engineering Materials 728 (January 2017): 367–72. http://dx.doi.org/10.4028/www.scientific.net/kem.728.367.
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The effect of mineral admixtures on compressive and tensile strength of concrete was studied in the article. The concrete mixtures were modified by quart, quartz-feldspar and basalt powder in amount 10, 20 and 30 % by weight of cement. The mix with no mineral admixture was prepared as a control sample. The results obtained show that selected mineral admixtures lower concrete strength but the degree of strength reduction depends on the used mineral admixture and its concentration.
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Li, Yun Feng, Yang Liu, Rong Qiang Du, and Fan Ying Kong. "Effect of Steel Slag Powder on the Durability of High Performance Concrete." Advanced Materials Research 79-82 (August 2009): 175–78. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.175.
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dvanced mineral admixtures can lead to economical high performance concrete with enhanced durability and reduced cement content. When super fine steel slag powder is mixed into concrete as active admixture, resistance to abrasion and resistance to chloride penetration are improved as well as workability and mechanical properties of the concrete. Resistance to abrasion of steel slag concrete is measured and resistance to chloride penetration is also determined by the method of NEL and ASTM C1202 in this paper. Result shows that compound mineral admixtures as partial replacement for Portland cement in mortar enhance abrasion resistance. Mixing mineral admixture is an effective means for controlling the chloride permeability. Concrete specimens prepared with compound mineral admixture with steel slag powder and blast furnace slag powder has very low permeability.
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Khan, Sadaqat Ullah, Muhammad Fadhil Nuruddin, Tehmina Ayub, and Nasir Shafiq. "Effects of Different Mineral Admixtures on the Properties of Fresh Concrete." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/986567.
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This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.
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Wang, Xue Fang, and Jian Lan Zheng. "Influence of Compounded Mineral Admixtures on Shrinkage and Early-Age Cracking Behaviors of Concrete." Advanced Materials Research 450-451 (January 2012): 738–42. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.738.
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Influence of compounded mineral admixtures on shrinkage and early-age cracking behaviors of concrete was studied, based on the fellow factors: fly ash to blast furnace slag(denoted as BSF) ratio, fly ash-metakaolin ratio, BSF-silica fume ratio. Research shows that the Pozzolanic admixtures compounded with cementitious admixtures have complementary and synergistic effect for hydration progress of concrete, which can enhance the volume stability and cracking behaviors of concrete. However, the pozzolanic admixture compounded with other pozzolanic admixture, two pozzolanic admixtures will grab Ca(OH)2 resource. And then if the dosage of mineral admixture is higher, the compounding will result to decrease the volume stability and cracking behaviors of concrete.
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DING, Xiangqun, Tingyu LI, and Baoxin YANG. "Experimental Study on the Effect of Ultrafine Mineral Admixtures on the Mechanical Properties of Cement Mortar." Progress in Chinese Materials Sciences 2, no. 1 (2023): 1–7. http://dx.doi.org/10.48014/pcms.20230306001.
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Objective: The effect of ultrafine mineral admixtures on the mechanical properties of grouting mortar was studied. Methods: In this paper, the compressive strength and flexural strength of the mortar with different contents of ultrafine mineral admixture replacing cement were tested respectively, and the heat of hydration was tested. XRD and SEM were used to analyze the changes in the microstructure characteristics after the addition of ultrafine mineral admixture. Results: after the addition of 5% ultrafine mineral admixture, the fluidity of cement slurry decreased by 25. 3%, and the fluidity gradually decreased with the gradual increase of ultrafine mineral admixture. With the addition of superfine mineral addition, The compressive strength increased steadily and gradually decreased thereafter, while the content of superfine mineral added was 20%, the strength of rubber sand reached the maximum value at 28 days, which increased by 23. 76% compared with the test block without admixture. The flexural strength of 3d and 7d of rubber sand was weakened by the incorporation of ultrafine mineral admixture, and the flexural strength of 28d increased slowly with the incorporation of ultrafine admixture, and the flexural strength value reached the maximum when the dosage was 25%. The heat of hydration and microstructure analysis showed that the sand system produced more hydrated calcium silicate gel filling into the structure of the sand after the addition of ultrafine mineral admixture. Conclusion: a certain amount of ultrafine mineral admixture has remarkable influence on the compression strength of rubber sand, and the flexural strength of 3d and 7d is weakened, and increases the flexural strength of 28d.
Dissertations / Theses on the topic "Mineral Admixture"
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Adjoudj, Mhamed. "Effet des additions minérales et organiques sur le comportement rhéologique du béton." Thesis, Cergy-Pontoise, 2015. http://www.theses.fr/2015CERG0784/document.
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L'emploi de certaines additions minérales et organiques dans la confection du mortier et du béton contribue à une modification du processus d'hydratation du ciment. L'incorporation de ces additions minérales entraîne également une modification de la distribution granulaire, l'apparition de nouveaux sites de nucléation et une nouvelle activité des surfaces des grains. Ceci nécessite le malaxage avec des superplastifiants qui viennent défloculer les grains, libérer l'eau piégée dans les interstices et améliorer l'ouvrabilité du béton. Ces modifications des propriétés physicochimiques des composants du béton affectent directement les propriétés rhéologiques du mortier et du béton à l'état frais ainsi que ses composantes finales.L'objectif principal de ce travail est focalisé sur la prédiction des modifications rhéologiques apportées par les additions minérales aux mortiers afin de trouver les meilleures compositions d'une mise en œuvre convenable. Une étude expérimentale est entamée sur des mortiers normalisés où le ciment ordinaire est substitué partiellement par différentes additions minérales telles que la fumée de silice, le laitier des hauts fourneaux, la pouzzolane naturelle et le calcaire. Avec l'eau de gâchage, on a ajouté plusieurs types de superplastifiants avec différents dosages où les paramètres rhéologiques du mortier ont été mesurés respectivement par un mini cône et un rhéomètre.Les paramètre rhéologiques obtenus varient sensiblement avec chaque type d'addition minérale et dépendent de ses propriétés et son interaction avec le superplastifiant et les grains de ciment. Le superplastifiant à base de polycarboxylates est plus efficace en présence du ciment contenant du calcaire ou du laitier conduisant à une amélioration des propriétés rhéologiques. Par contre, le mortier devient plus visqueux s'il contient un fort pourcentage de pouzzolane naturelle. Une relation mathématique est proposée qui exprime la variation de chaque paramètre rhéologique selon le taux de substitution du ciment et le dosage en superplastifiant. Cette relation est exprimée par le produit de trois paramètres; l'effet de l'addition minérale, l'effet du superplastifiant et l'effet de leur interaction. Les coefficients de corrélation trouvés sont proches de l'unité et justifient bien la convenance de ce choix. L'application de cette nouvelle relation à d'autres résultats trouvés par d'autres chercheurs présente une grande satisfaction avec des résultats satisfaisant et des coefficients de corrélation allant 0,9 à 0,98<br>The use of some organic and inorganic admixtures in the production of mortar and concrete contributes to a change in the cement hydration process. The incorporation of these mineral additions also causes a change in the grain distribution, the appearance of new nucleation sites and a new activity of the grain surfaces. This requires mixing with superplasticizers which deflocculates grains, releases the trapped water in the interstices and improves the workability of concrete. These changes in the physicochemical properties of the cement paste directly affect the rheological properties of mortar and concrete in the fresh state and its final components.The main objective of this work is focused on the prediction of rheological changes of mineral additions mortars and finds the best composition for a suitable casting. An experimental study is underway on standardized mortars where ordinary cement is partially substituted by different mineral additions such as silica fume, blast furnace slag, natural pouzzolan and limestone powder. With the mixing water, was added several types with different dosages of superplasticizers where the rheological parameters of the mortar were measured respectively by a rheometer apparatus and a mini cone test.The Theological parameters obtained vary with each type of mineral addition and depend on its properties and its interaction with the superplasticizer and cement grains. The polycarboxylate superplasticizer is more effective in the presence of limestone powder or cement containing slag resulting in improved rheological properties. However, the mortar becomes more viscous if it contains a high percentage of natural pozzolan. A mathematical relationship is provided which expresses the variation of each rheological parameter according the substitution rate of the cement and superplasticizer dosage. This relationship is expressed by the product of three parameters; the effect of the mineral addition, the effect of the superplasticizer and the effect of their interaction. The correlation coefficients found are close to unity and well justify the appropriateness of this choice. The application of this new relationship to other results found by other researchers has high satisfaction with satisfactory results and correlation coefficients ranging from 0.9 to 0.98
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Yazan, Kazim. "Effects Of Retempering With Superplasticizer On Properties Of Prolonged Mixed Mineral Admixture Containing Concrete At Hot Weather Conditions." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606751/index.pdf.
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Concrete which is manufactured in a mixing plant to be delivered to construction site in unhardened and plastic stage is called ready-mixed concrete. Because of technical and economical reasons, many mineral and chemical admixtures are used in ready-mixed concrete production.
As a result of extra mixing and delayed placing of ready-mixed concrete (especially at hot weather conditions), there can be many problems about concrete, like slump loss.
Addition of water for retempering concrete is the usual procedure, but addition of water without proper adjustment in mixture proportions, adversely affects compressive strength.
During this study, effects of prolonged mixing and retempering with superplasticizer on properties of fresh and hardened concrete at hot weather conditions are observed. Some of the properties of concrete inspected are compressive strength, splitting tensile strength, slump and air content. All mixes contain air entrainer and water reducer at a standard amount. The difference between mixes comes from kind and amount of mineral admixture which cement is replaced by. During the study, fly ash, blast furnace slag, ground clay brick and natural pozzolan are used at amounts, 25% and 50% of cement. Also, a mixture of pure cement is prepared as control concrete.
15 cm initial slump is planned in the experimental work. After five minutes and at the end of first, second, third and fourth hours of mixing process, if needed retempering process is proceeded with superplasticizer and samples are taken. As a result of retempering with superplasticizer, the aimed slump values are obtained. The effects are than, observed.
As a result of this study, it has been observed that replacing Portland cement with certain mineral admixtures, especially fly ash at certain amounts, can be a solution for slump loss problem, by retarding the slump loss effect of prolonged mixing. Also it has been seen that ground clay brick causes better performance for slump values at lateral stages of mixing with respect to pure Portland cement. Another important observation has been about the increase in the amount of air caused by air entraining admixtures in fresh concrete based on prolonged mixing at hot weather conditions.
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Christianto, Heru Ari. "Effect Of Chemical And Mineral Admixtures On The Fresh Properties Of Self Compacting Mortars." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605322/index.pdf.
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Fresh properties of mortars are important factors in altering the performance of self compacting concrete (SCC). Measurement of the rheological properties of the fine mortar part of concrete is generally used in the mix design of SCC. It can be stated that SCC rheology can be optimized if the fine mortar part of concrete is designed properly. However, measurement of the rheological properties is often impractical due to the need for complex equipment. Therefore, more practical methods of assessing mortar workability are often preferred.
In this study, four mineral admixtures, three superplasticizers (SP) and two viscosity modifying admixtures (VMA) were used to prepare self compacting mortar (SCM). The mineral admixtures included fly-ash, brick powder, limestone powder, and kaolinite. Two of the SPs were polycarboxylate based and another one was melamine formaldehyde based. One of the viscosity modifying admixtures was based on an aqueous dispersion of microscopic silica and the other one was based on high molecular weight hydroxylated polymer.
Within the scope of the experimental program, 43 mixes of SCM were prepared from different materials with keeping the amount of mixing water constant. Workability of the fresh mortar were determined using V - funnel and slump flow tests. The setting time of the mortars, were also determined. The hardened properties that were determined included the ultrasonic pulse velocity (UPV) and the strength which was determined at 7, 28, and 56 days.
It was concluded that among the mineral admixtures used, only fly-ash and limestone powder increased the workability of the mixes. The two polycarboxylate based SPs yield approximately the same workability and the melamine formaldehyde based SP was not as effective as the other two.
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Delibas, Tughan. "Effects Of Granulated Blast Furnace Slag Trass And Limestone Fineness On The Properties Of Blended Cements." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614072/index.pdf.
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The aim of this research was to determine the effects of the fineness of different mineral additives on loss on ignition, heat of hydration, physical, mechanical and chemical properties of blended cements. For that purpose, portland cement clinker was replaced with granulated blast furnace slag (GBFS), natural pozzolan (NP) and limestone (L) at 6%, 20% and 35% replacement levels. Blended cements containing GBFS and NP were ground to a fineness of 3000, 5000 and 6000 cm2/g. Cements containing L were ground to 3000 cm2/g, 4000 cm2/g and 4500 cm2/g. All of the blended cement types mentioned above were both interground and separately ground to the specified fineness levels. Therefore, a total of 57 different cements were produced. Loss on ignition, heat of hydration, chemical, mechanical and physical analyses were performed on the produced cements. Moreover, the chemical analyses of the cements were obtained for cement particles finer (-45&mu<br>m) and coarser (+45&mu<br>m) than 45 &mu<br>m in order to determine the ingredients of -45 &mu<br>m, which is known to be more reactive.
As a result it was shown that the grindability differences of the cement ingredients affect the properties of blended cements. An increase in the specific surface area increases both the compressive strength and heat of hydration values and adversely affects the loss on ignition
values. The results also showed that if the cement particles were ground finer, it was more prone to moisture which resulted in higher loss on ignition values after longer periods.
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Ivan, Lukić. "Komparativna analiza osnovnih svojstava konstrukcijskih betona spravljenih sa različitim vrstama lakih agregata." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2015. http://www.cris.uns.ac.rs/record.jsf?recordId=93149&source=NDLTD&language=en.
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U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja na osnovu kojih je izvršena komparativna analiza uticaja različitih vrsta lakih agregata i vrste i količine cementa na osnovna fizičko-mehanička svojstva lakoagregatnih betona. Takođe, analizirana je i mogućnost zamene dela cementa mineralnim dodacima u cilju smanjenja negativnih uticaja proizvodnje betona na životnu sredinu. Rezultati su pokazali da je primenom svih analiziranih vrsta agregata moguće dobiti konstrukcijski lakoagregatni beton, čak i sa manjim količinama cementa, odnosno sa zamenom dela cementa mineralnim dodacima, kao i da je moguće uspostaviti pouzdane korelacione veze između pojedinih svojstava betona i primenjenih komponentnih materijala.<br>In dissertation are presented results of own experimental research of acomparative analysis of the impact of different types of lightweightaggregates and the type and quantity of cement on basic physical andmechanical properties of structural lightweight concrete. Also, the possibilityof replacing part of cement with mineral admixtures is analyzed in order toreduce the negative impact of concrete production on the environment. Theresults showed that it is possible to obtain structural lightweight aggregateconcrete with all types of lightweight aggregates and even with lowerquantities of cement or with a replacement of part of a cement with mineraladmixtures. Also, it is possible to establish a reliable correlation betweencertain properties of concrete and used component materials.
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Anjos, Marcos Alyssandro Soares dos. "Adi??o do res?duo de biomassa da cana-de-a??car em pastas para cimenta??o de po?os petrol?feros produtores de ?leos pesados." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12742.
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Previous issue date: 2009-04-02<br>The Potiguar basin has large fields of viscous oil where the used method for recovering is based on vapor injection; this operation is carried out by injecting vapor in the oilwell
directly, without the protection of a revetment through thermal insulation, what causes its dilation and, consequently, cracks in the cement placed on the annular, and lost of hydraulic insulation; this crack is occasioned by the phenomenon of retrogression of the compressive resistance due to the conversion of the hydrated calcium silicate in
phases calcium-rich, caused by the high temperatures in the wells, subjected to thermal recuperation. This work has evaluated the application of composite pastes with addition
of residue of biomass of ground sugar-cane bagasse as anti-retrogression mineral admixture for cementation of oil-wells subjected to thermal recuperation. The addition of the mineral residue was carried out considering a relative amount of 10, 20, 30, 40 and 59% in relation to cement mass, trying to improve the microstructure of the paste, still being developed a reference paste only with cement and a paste with addition of 40% of silica flour - renowned material in the oil industry as anti-retrogression additive. Pozzolanic activity of the ash was evaluated through XRD, TG/DTG, as the resistance
to compression, and it was also determined the physical and mechanical behavior of the pastes when submitted to cure at low temperatures (22 and 38? C); besides it was evaluated the behavior of the pastes when submitted to two cycles of cure at high temperature (280?C) and pressure (7 MPa). It was verified that the ash of the sugar-cane biomass presents pozzolanic reaction and has great efficiency in decrease the
permeability of the paste by filler effect, as well as that addition of ash in a relative amount of 10, 20 e 30% increases cured compressive resistance at low temperatures. It
was also showed that the ash in a relative amount of 40% and 59% has very significant efficiency as anti-retrogression additive, since it prevents the decrease of compressive
resistance and forms hydrated calcium silicate type xenotlita and tobermorita which have more resistance and stability in high temperatures<br>A bacia Potiguar tem grandes campos de ?leo viscoso, onde o m?todo de recupera??o utilizado ? a inje??o de vapor; essa opera??o ? realizada injetando-se vapor diretamente
no po?o, sem a prote??o do revestimento atrav?s de isolamento t?rmico, o que provoca a dilata??o do mesmo, provocando assim falhas no cimento colocado no anular, e
conseq?entemente, perda do isolamento hidr?ulico, esta falha tem origem no fen?meno de retrogress?o da resist?ncia ? compress?o devido a convers?o do silicato de c?lcio
hidratado em fases ricas em c?lcio, provocada pelas elevadas temperaturas nos po?os, sujeitos ? recupera??o t?rmica. O presente trabalho avaliou a aplica??o de pastas comp?sitas com adi??o de res?duos de biomassa do baga?o da cana-de-a??car mo?das como aditivo mineral anti-retrogress?o para cimenta??o de po?os petrol?feros sujeitos a recupera??o t?rmica. A adi??o do res?duo mineral foi realizada teores de 10, 20, 30, 40 e 59% em rela??o a massa do cimento, visando melhorar a microestrutura da pasta, sendo ainda produzidas uma pasta de refer?ncia, apenas com cimento e uma pasta com adi??o de 40% de silica flour material consagrado na ind?stria de petr?leo como aditivo antiretrogress?o. Foram avaliados a atividade pozol?nica da cinza atrav?s de DRX, TG/DTG e resist?ncia ? compress?o, determinando-se tamb?m o comportamento f?sico e mec?nico das pastas submetidas a cura com baixas temperaturas (22 e 38?C), al?m da avalia??o do comportamento das pastas submetidas a dois ciclos de cura a alta temperatura (280?C) e press?o (7 MPa). Verificou-se que a cinza de biomassa da cana apresenta rea??o pozol?nica, tendo grande efici?ncia na diminui??o da permeabilidade da pasta por efeito filler, e que as adi??es de cinza em teores de 10, 20 e 30% aumentam a resist?ncia ? compress?o das pastas curadas a baixas temperaturas. Constatou-se ainda que a cinza em teores de 40% e 59% tem ?tima efici?ncia como aditivo antiretrogress?o, pois evitam a diminui??o da resist?ncia ? compress?o e formam silicato de c?lcio hidratado do tipo xenotlita e tobermorita que se apresentam mais resistentes e est?veis as altas temperaturas
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劉艷 and Yan Liu. "Preventive effects of mineral admixtures on Alkali-Silica reaction." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31244531.
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Darwish, Abdulhanan A. "Development of high performance concrete using combinations of mineral admixtures." Thesis, University of Sheffield, 1995. http://etheses.whiterose.ac.uk/3066/.
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Cement replacement materials are by-products used to produce high performance concrete. Published data on the effects of combinations of mineral admixtures in concrete on the microstructural and performance-related properties under different curing regimes are comparatively little. Further the correlation of strength of concrete to its permeability and pore structure is also not clear. The main objective of this research is to study the performance of various combinations of fly ash/silica fume and slag/silica fume concretes under three different curing regimes, viz. continuous moist curing, no moist curing after demolding and air drying after 7-days of initial moist curing. Six different concrete mixes were prepared with ordinary portland cement and a blend of portland cement and combinations of fly ash+silica fume and slag+silica fume The water-to-cementitious materials ratio of all the concrete mixtures was kept constant at 0.45. The properties investigated included workability of the fresh concrete, engineering properties such as cube and modified cube compressive strength, flexural strength, dynamic modulus of elasticity, pulse velocity, shrinkage and swelling, permeability and microstructural properties such as porosity and pore size distribution. The results show that prolonged dry curing results in lower strengths, higher porosity, coarser pore structure and more permeable concretes. It was found that the loss in early age compressive strength due to incorporation of fly ash or slag can be compensated for by the addition of small amounts of silica fume. The engineering and microstructural properties and permeability of concretes containing fly ash or slag appear to be more sensitive to poor curing than the control concrete, with the sensitivity increasing with increasing amounts of fly ash or slag in the mixtures. The incorporation of high volumes of slag in the concrete mixtures refined the pore structure and produced concretes with very low porosity and threshold diameters. The results emphasize that a minimum 7-day wet curing is needed for concrete with mineral admixtures to develop the full potential, and that continued exposure to a drying environment can have adverse effects on the long-term durability of inadequately cured slag or fly ash concretes. The results also confirm that compressive strength alone is not an adequate index to judge the performance of concrete, and the knowledge of the strength, pore structure and permeability are required for this purpose. Slag/silica fume concrete mixtures showed better performance than fly ash/silica fume concrete mixtures as regards the development of engineering and microstructural properties.
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LIMA, Marcelo Batista. "Avaliação da capacidade de proteção contra a corrosão da arma-dura induzida por cloretos de concretos com adições minerais e inibidores de corrosão." Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/1347.
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Previous issue date: 2009-09-28<br>Increasing the durability of concrete structural elements is primordial, especially those related to power generation in eolic areas that are subjected to the phenomenon of reinforcement corrosion. In this context, this study aims to evaluate the overall protection ability of concrete to the phenomenon of reinforcement corrosion induced by chlorides. To this end, it was adopted a statistical program based on a fractional factorial design in which the variables studied were as follows: the water-binder ratio (0.35, 0.45 and 0.55), the type of mineral admixture (silica fume and blast furnace slag at specific levels), the type of corrosion inhibitor (calcium nitrite, sodium nitrite and amine) and the level of corrosion inhibitor (minimum and maximum recommended by each manufacturer). In the concrete investigations, the tests performed were corrosion potential, polarization resistance and electrochemical impedance. Throughout the experiments, it was possible to testify the beneficial effect of reducing the water-binder ratio. It was also possible to prove the very positive effect of the incorporation of mineral admixtures, especially of silica fume. The satisfactory performance of various inhibitors evaluated was also verified, specially when concrete contains mineral admixtures. A parallel study was conducted to make a comparative analysis of inhibitors at the same range of concentrations (at solid levels of 0.76%, 2.21% and 3.66% of the compound on the cement mass), nevertheless this study have demonstrated that fixing contents for all inhibitor is not appropriated, and the recommended dosages by the manufacturer is the best condition. As the levels recommended by manufacturers, it was found that the higher percentages have not worked well for sodium nitrite otherwise, for amine and nitrite calcium, the higher levels implied better results. Regarding the tannin inhibitor also assessed in the parallel study mentioned above (related to specific inhibitors), its good performance related to corrosion inhibition happened just for the content of 0.76% (the lowest levels). For the other contents, it was verified anomalous results. These results demonstrated that each type of corrosion inhibitor has its optimal concentration for use in concrete. Based on a cost-benefit analysis and evaluating the increase in the concrete value for cubic meter (in R$) in the presence of inhibitors at the same contents, it was verified a relative parity prices among the tested nitrites and an extremely high cost of amine. However, when performing the same analysis but using the levels recommended by the manufacturers for each inhibitor independent, it was found that the large disparity in prices between nitrite and amine was reduced considerably. An assessment of technical and economic feasibility was also performed based on the efficiency of corrosion inhibition and cost per cubic meter of concrete mixtures that did not show a typical depassivation of their stell bar up to the attack age evaluated<br>O aumento da durabilidade é um aspecto primordial para os elementos estruturais de concreto, em especial aqueles constituintes das estruturas de geração de energia em parques eólicos, sujeitos ao fenômeno de corrosão das armaduras. Nesse contexto, este trabalho tem como objetivo geral avaliar a capacidade de proteção de diferentes concretoS frente ao fenômeno da corrosão da armadura induzida por cloretos. Para tanto, foi adotado um planejamento estatístico baseado em um modelo fatorial fracionado em que as variáveis estudadas foram: a relação água/aglomerante (0,35; 0,45 e 0,55), o tipo de adição mineral (sílica ativa e escória de alto-forno, em teores específicos), o tipo de inibidor de corrosão (nitrito de cálcio, nitrito de sódio e amina) e o teor de inibidor de corrosão (mínimo e máximo recomendado por cada fabricante). Na avaliação dos concretos, foram realizados ensaios de potencial de corrosão, resistência de polarização e impedância eletroquímica. Ao longo de todo experimento foi possível constatar o efeito benéfico da redução da relação a/agl. Também foi possível verificar o efeito extremamente positivo da incorporação das adições minerais, em especial da sílica ativa. Constatou-se também o efeito positivo dos diversos inibidores avaliados, em seus teores mínimo e máximo, beneficio que se mostrou mais pronunciado quando da utilização conjunta com as adições minerais. Um estudo paralelo foi realizado para se fazer uma análise comparativa dos inibidores dentro da mesma faixa de teores empregados (teores de 0,76%; 2,21% e 3,66% de sólidos do aditivo em relação à massa de cimento), no qual se verificou que a utilização desses teores fixos para os diferentes tipos de inibidores não se mostrou tão eficiente quanto em relação à utilização dos aditivos na dosagem de recomendação do fabricante. Quanto a estes teores (recomendados pelos fabricantes), verificou-se que os percentuais mais altos não funcionaram bem para o nitrito de sódio, ao passo que para a amina e para o nitrito de cálcio os teores mais elevados resultaram em melhores resultados. Em relação ao tanino, inibidor que também foi avaliado no estudo paralelo referido anteriormente (específico sobre os inibidores), só houve algum resultado de inibição de corrosão para o teor de 0,76% (mais baixo dos teores), tendo-se obtido resultados anômalos para os outros 2 teores mais altos. Tais resultados permitiram constatar que cada tipo de inibidor de corrosão possui sua concentração ótima de utilização no concreto. Fazendo-se uma análise de custo e avaliando-se o acréscimo em Reais no valor do m3 do concreto proporcionado pelos diversos aditivos inibidores e nos teores de mesma faixa de emprego, verificou-se uma relativa paridade de preços entre os nitritos e um elevadíssimo custo da amina. No entanto, ao se realizar a mesma análise, mas utilizando os teores recomendados pelos fabricantes de cada inibidor, verificou-se que a grande disparidade de preços entre os nitritos e a amina foi reduzida de forma considerável. Uma avaliação da viabilidade técnico-econômica dos concretos também foi realizada, a partir dos dados de eficiência de inibição à corrosão e custo/m3 das misturas que não apresentaram comportamento típico de despassivação de suas armaduras até a idade de ataque considerada
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Tran, Victor. "Effect of Mineral and Chemical Admixtures on Durability of Cementitious Systems." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/6040.
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Mineral and chemical admixtures are used today in almost all concrete mixtures to improve concrete fresh and hardened properties, and to enhance concrete durability. In this study, four mineral and four chemical admixtures were investigated: namely, metakaolin (MK), silica fume (SF), Class F fly ash (FA), blast-furnace slag (BFS), two high-range water reducers (SP), water reducer/retarder (WRD), and air-entrainer (AEA). The objective of this study is to assess the effects of commonly used mineral and chemical admixtures on the durability of the cementitious system. Two durability issues were addressed in this study: the potential of the cementitious system to generate heat, and sulfate durability. The properties studied here included heat of hydration (HOH) measurements using isothermal calorimetry, setting properties, compressive strength, and expansion on exposure to a sodium sulfate solution. X-ray diffraction was used to characterize the as-received materials and explain failure trends.
The findings of this study indicate that silica fume inclusion sustains superior durability in comparison to the other mineral admixtures considered here. Replacement levels as low as 10% outperformed the other admixtures studied. Fly ash showed improvement in the workability of the mixes, but had the lowest compressive strength results and might pose challenges when the rate of strength gain is critical. However, Class F fly ash mixtures showed better performance than unblended mixtures when exposed to a sulfate source. Metakaolin mixes showed higher heat evolution among all the mixtures studied here. This can potentially lead to durability concerns, especially when temperature rise is a design concern. Blast-furnace slag also improved the workability of the mixes and the later compressive strength, but had mixed performances when examined for sulfate durability.
Books on the topic "Mineral Admixture"
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Bapat, Jayant D. Mineral admixtures in cement and concrete. Taylor & Francis, 2012.
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Göske, Jürgen. Die mineralogisch-chemische Barriere: Fixierung der Anionen SO[subscript 4]²[minus], Cl[minus], NO[subscript 3 minus], und CrO[subscript 4]²[minus] in Speichermineralen, unter dem Aspekt verschiedener Rohstoffmischungen, Abmischungen und Modelkonzentrationen = The mineralogical chemical barrier : fixation of the anions SO[subscript 4]²[minus], Cl[minus], NO[subscript 3 minus] and CrO[subscript 4]²[minus] in storage minerals with aspect to various mixtures of raw materials, admixtures and model concentrations. Institut für Geologische Wissenschaften und Geiseltalmuseum der Martin-Luther-Universität Halle-Wittenberg, 1999.
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Satish Rao & Sandeep Salhotra. To Study the Fire Resistance of Waste Pet Fibre Concrete (fibre Coated with Mineral Admixture). Independently Published, 2018.
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Tokyay, Mustafa. Cement and Concrete Mineral Admixtures. Taylor & Francis Group, 2016.
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Tokyay, Mustafa. Cement and Concrete Mineral Admixtures. Taylor & Francis Group, 2016.
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Tokyay, Mustafa. Cement and Concrete Mineral Admixtures. Taylor & Francis Group, 2019.
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Bapat, Jayant D. Mineral Admixtures in Cement and Concrete. Taylor & Francis Group, 2012.
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Bapat, Jayant D. Mineral Admixtures in Cement and Concrete. Taylor & Francis Group, 2017.
Find full textBook chapters on the topic "Mineral Admixture"
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Tang, Xiong, Guoqiang Xiang, and Jie Zou. "Research on Salt Corrosion Resistance Design of Highway Concrete Structures." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-4355-1_11.
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AbstractIn response to the problem of salt corrosion on highway concrete structures in high-altitude areas, this article studies the effects of water cement ratio, admixtures, and admixtures on the salt corrosion resistance of concrete through salt freezing cycle tests and salt freezing erosion resistance tests. The results indicate that under the conditions of meeting the workability of concrete, when the water cement ratio is below 0.4, the resistance to salt freezing and erosion is excellent. When the air content of concrete is between 0 and 3.8%, the salt freezing resistance and corrosion resistance of concrete increase with the increase of air content. When the air content exceeds 3.8%, the impact of the increase of air content on its performance decreases. It is advisable to use silica fume as the active mineral admixture for concrete in the admixture. If fly ash or mineral powder is used as the mineral admixture, the curing period must be extended.
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Tai, Wei, Xiaogen Tong, Kaifeng Zhang, and Zuoqiu Luo. "Effect of Iron Tailings Fine Powder as Admixture on the Properties of Cement Mortar and Concrete." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-2417-8_25.
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AbstractThe paper conducts feasibility tests on iron tailings fine powder as concrete mineral admixture, and compares its performance with traditional admixture fly ash and ground limestone powder to make effective use of stone powder resources. The fluidity and mechanical properties of cement mortar of the three admixtures are respectively tested. And the influence on compressive strength, shrinkage and chloride penetration resistance of C30, C35 and C40 concrete under different curing conditions. The results show that the chemical composition of iron tailings is similar to that of fly ash and belongs to siliceous powder. The 1, 2 and 3 h mobility losses of iron tailings and fly ash are similar, but higher than those of limestone powder. The mortar strength of the first three admixtures at 14d age is close to that of the other two admixtures at 14–60d age, and the activity index and strength change with age are consistent. Under different curing conditions, the compressive strength of the three kinds of admixture concrete is as follows: fly ash concrete > iron tailings powder concrete > limestone powder concrete; The addition of iron tailings is beneficial to improve the shrinkage performance and chloride ion penetration resistance of concrete, and can play a role in filling the micro-pore structure, which has the technical feasibility as an inert admixture.
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Yu, Lei, Tianyuan Zhao, and Zhi Wang. "Study on the Properties of Concrete with Different Admixtures in Acid Corrosive Environment." In Advances in Frontier Research on Engineering Structures. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8657-4_21.
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AbstractTo study the deteriorating law and find a proper admixture to enhance the durability of the concrete in the acid corrosion environment, the corrosion and deterioration of concrete with different types and proportions of admixtures were studied. The appearance morphology, strength, chloride penetration depth, and porosity of ordinary concrete and concrete with different types of admixtures under water curing and corrosion solution erosion were compared. The results show that in terms of improving the corrosion resistance of concrete, the single-mixed mineral powder shows excellent performance. The addition of fly ash significantly increases the content of 10–100 nm pores, and the strength is low at an early age, but the strong growth is limited at the later stage.
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Dvorkin, Leonid, Vadim Zhitkovsky, Nataliya Lushnikova, and Yuri Ribakov. "Metakaolin as Mineral Admixture for Cement-based Composites." In Metakaolin and Fly Ash as Mineral Admixtures for Concrete. CRC Press, 2021. http://dx.doi.org/10.1201/9781003096825-4.
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Khode, Bhalchandra V., and Sujesh D. Ghodmare. "Effect of Mineral and Chemical Admixture for Improvement of High-Performance Concrete." In Smart Technologies for Energy, Environment and Sustainable Development. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-6148-7_41.
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Joanna, P. S., K. Pankajakshan, Hariprasad Madhavan, P. Vikram Srinivas, and Syed Farjaz Farooq. "Mechanical Properties of GGBS Based Concrete Added with CO2 as Mineral Admixture." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-7043-4_11.
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Bhat, Ishfaq Ahmad, Khushpreet Singh, and Nittin Sharma. "Influence of Mineral Admixture on Acceleration Carbonation Curing of Concrete: A Review." In Lecture Notes in Civil Engineering. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6557-8_81.
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Li, Meng, Guangxiu Fang, Haonan Wu, Chunming Wang, Huaiyu Li, and Zhoutong Li. "Experimental Study on Strength of Luminous Concrete with Double Admixture of Fly Ash and Slag Powder." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-4090-1_31.
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AbstractLuminescent concrete is based on ordinary concrete, in which zinc sulfide luminescent material is added to make ordinary concrete with luminescent function of concrete, and its mechanical properties are greatly affected by the dosage of luminescent powder and mineral admixture. In order to study the mechanical properties and optical properties of luminescent concrete, luminescent concrete composite adding different dosages of fly ash and slag powder compressive test and flexural test, obtained different fly ash and slag powder dosage of luminescent concrete compressive strength and flexural strength with the curing time of the change curve and based on this proposed luminescent concrete compressive strength and flexural strength of the correction coefficient, for the subsequent light-emitting concrete. The research and engineering application of luminous concrete provides theoretical basis.
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Majhi, Biswajit, and Soumya Saswat Priyadarshi. "Development of Sustainable Concrete with Treated Pulverized Used Foundry Sand as Mineral Admixture." In Advances in Sustainable Construction Materials. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4590-4_65.
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Guo, Liangyu, Fushan Ma, and Binhui Zhao. "Study on the Durability of Manufactured Sand Concrete with the Change of Mix Proportion Parameters." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. https://doi.org/10.1007/978-981-97-6238-5_9.
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AbstractCement, aggregate, mineral admixture, concrete admixture, and mixing water were used as the main raw materials to prepare manufactured sand concrete. By adjusting the proportioning parameters of manufactured sand concrete, such as sand ratio and water-cement ratio, the influence of proportioning parameters on the durability of manufactured sand concrete was studied. Experimental results show that when the sand ratio is between 0.38 and 0.44, the mechanism of sand best workability and durability of the concrete strength, the best value for the mechanism of sand concrete, sand ratio range within the scope of the young stage of mechanism sand concrete stress is almost not affected by sand ratio increase, age stage mechanism of sand concrete stress along with the increase in sand ratio decreased significantly; The stress of natural medium sand concrete and manufactured sand concrete increases with the increase in the water-cement ratio, and the compressive strength of manufactured sand concrete is slightly higher than that of ordinary natural sand concrete. When the stone powder content is 10.5%, its filling performance is better, and the frost resistance of mechanized sand concrete can be improved by adjusting the stone powder content. When the powder volume is 158 dm3, the manufactured sand concrete has good workability and the highest durability. The increase in the water-binder ratio will lead to the aggravation of carbonization depth, serious carbonization phenomenon, and reduced durability of machined sand concrete.
Conference papers on the topic "Mineral Admixture"
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Thompson, Neil G., Kurt M. Lawson, David R. Lankard, and Yash Paul Virmani. "Effect of Concrete Mix Components on Corrosion of Steel in Concrete." In CORROSION 1996. NACE International, 1996. https://doi.org/10.5006/c1996-96334.
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Abstract A major cause of concrete deterioration on bridge structures is the corrosion of the embedded steel reinforcement. In response to the continued problem of corrosion, FHWA initiated this research aimed at (1) quantifying the corrosive conditions fostering concrete bridge deterioration and (2) identifying concrete materials which consistently provide superior performance when used in bridge applications. The experimental phase of this research project was divided into three tasks: Corrosive Environments Studies, Concrete Chemical and Physical Properties, and Long-Term Corrosion Performance. This paper reviews the results of the study of the effects on corrosion of chemical components of concrete. Experiments were performed to identify the chemical components of concretes that affect corrosion induced deterioration of concrete structures. The dependent variables of interest in examining corrosion induced deterioration of concrete are corrosion rate, corrosion potential, chloride permeability, electrical resistivity, and compressive strength. This paper focuses on the corrosion properties. The independent concrete component variables examined included: water-cement ratio, air content, coarse aggregate type, fine aggregate type, mineral admixture, and cement type. Because of the large number of independent variables and the number of levels of interest for the variables, an optimized experimental design was developed to permit the estimate of the main-effect terms for each independent variable. Models were developed to predict the effect of the independent variables on corrosion rate and corrosion potential in each of two environments.
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Sennour, M. L., H. Zhang, H. G. Wheat, and R. L. Carrasquillo. "Corrosion of Steel Bars in Concrete Containing Different Chemical and Mineral Admixtures." In CORROSION 1992. NACE International, 1992. https://doi.org/10.5006/c1992-92199.
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Abstract In the last decade, the use of various chemical and mineral admixtures in concrete has increased significantly. The admixtures utilized may affect concrete permeability, which in turn affects chloride penetration and corrosion of embedded steel bars. The effect of several admixtures in concrete on the corrosion behavior of embedded steel is described. The results were determined based on measurements of chloride permeability, chloride penetration, polarization resistance, macrocell current flow as well as visual observations.
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Sennour, M. L., H. Zhang, H. G. Wheat, and R. L. Carrasquillo. "Corrosion Susceptibility of Concrete Made with Different Chemical and Mineral Admixtures." In CORROSION 1993. NACE International, 1993. https://doi.org/10.5006/c1993-93337.
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Abstract The corrosion susceptibility of 12 mixes of concrete made with various amounts and types of chemical and mineral admixtures has been determined using a number of techniques. These techniques include such tests as measurements of chloride permeability, chloride penetration, polarization resistance, macrocell current flow as well as visual observations. The effect of several admixtures in concrete on the corrosion behavior of embedded steel is described.
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Nmai, Charles K., and Emmanuel K. Attiogbe. "Effect of Chemical and Mineral Admixtures on the Corrosion of Steel in Concrete." In CORROSION 1992. NACE International, 1992. https://doi.org/10.5006/c1992-92201.
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Abstract Reinforcing steel corrosion continues to be a major concern with regard to the durability of reinforced concrete structures. Most design engineers now utilize one or more corrosion inhibiting systems to ensure that reinforced concrete structures can attain their design lives without the need for extensive rehabilitation. A number of chemical and mineral admixtures which inhibit the corrosion of steel in concrete are available to the concrete industry. Included in this list is a newly developed water-based organic corrosion inhibitor. In this paper, the effect of some of these admixtures on the corrosion of steel in concrete is presented and discussed. Data is presented to show the relative performance of these admixtures in uncracked and cracked concrete specimens. The mechanism by which corrosion inhibition is obtained in each situation is also discussed.
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Ahn, Woosuk, Darrell Joque, and Arnfinn Rusten. "A Study on Corrosion Resistance of Prestressed Marine Concrete Piles." In CORROSION 2003. NACE International, 2003. https://doi.org/10.5006/c2003-03239.
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Abstract This study addresses the resistance to chloride ion penetration in the prestressed concrete large diameter cylinder piles exposed to the severe marine splash/tidal zone. Time to initiation of corrosion was predicted by using the Fick’s 2nd law for chloride penetration. The effects of water to binder ratio (w/b), mineral admixtures, and cover thickness were evaluated by the comparative studies, based on one-dimensional direct calculation, two-dimensional analysis using a computer software application, and case studies. The influences of environmental characteristics, manufacturing process, and local experiences were taken into account. The findings include i) the remarkable durability enhancement for the utilization of low w/b high strength concrete mixture, compared with the increase of cover thickness, ii) the ineffectiveness of fly ash inclusion, and iii) the importance of selection of manufacturing process, structural design, and construction procedure.
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Vanama, Raghava Kumar, and Balaji Ramakrishnan. "Effectiveness of Epoxy and Moisture-cure Polyurethane Coatings in Corrosion Mitigation of Embedded Rebar- an Experimental Study." In CORROSION 2020. NACE International, 2020. https://doi.org/10.5006/c2020-14405.
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Abstract Chloride induced corrosion is the prime reason for the degradation of embedded rebar in reinforced concrete marine structures. The present study experimentally investigates the effectiveness of traditional two-component epoxy (EPX), and moisture-cure polyurethane coatings (MC) applied on the concrete surface in reducing the rate of chloride ingression compared to the conventional concrete with and without mineral admixtures like fly ash and GGBS. Coatings used in the present study are characterized by XRD, EDAX, FEG-SEM, water uptake, adhesion strength and contact angle tests. Rapid chloride migration tests (RCMT) were conducted on concrete with and without coatings. Resistivity offered against the chloride migration monitored during the RCMT test indicated that concrete with MC shown higher resistivity in the initial period and continued to decrease over the test duration at a faster rate, unlike EPX. The non-steady-state migration coefficients of the concrete cured for 28days and coated with MC and EPX coatings were found to be nearly 22% and 48% of that of concrete with SCM cured for 84days respectively. The study is further extended to monitor the corrosion of rebar embedded in coated concrete subjected to corrosion acceleration until the first crack appeared on an uncoated specimen. Variation in current flow, half-cell potentials recorded during the acceleration test and actual mass loss of embedded rebar estimated by gravimetric analysis are presented in this paper.
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Tinnea, Jack, Ryan Tinnea, Dennis Burke, et al. "Evaluating Concrete Resistivity: Reducing Stray Current from DC Streetcars." In CORROSION 2007. NACE International, 2007. https://doi.org/10.5006/c2007-07276.
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Abstract A direct current (DC) streetcar project with rails embedded in the street is under development south of Lake Union in Seattle, Washington. DC trains can produce stray currents which can accelerate the corrosion of buried utilities. As a first line of defense this project employs an insulated formed rubber rail boot encased in the concrete track slab. A rubber boot encasing the rails provides a high resistance to earth and is an effective barrier providing a reduction of stray current discharges. Traditionally, Seattle Public Utilities (SPU) would have replaced any watermains within 10 feet parallel to the rail and crossings. The pipe was evaluated and found to have at least 100 years of useful life left if the pipe environment were to remain the same. If the pipe were replaced, SPU would coat the replacement pipe as a secondary barrier against stray current. If the pipe was to remain in the ground, a secondary protection measure would need to be evaluated. In an effort to augment traditional stray current control methods and significantly increase rail to earth resistance values at boot defects, it was decided to investigate the benefits of increased resistivity of the concrete track slab. Multiple track slab concrete mixes were tested to evaluate the impacts on resistivity of water reducers, a waterproofing agent and mineral admixtures including slag, fly ash, and condensed silica. To provide a comparative baseline, samples from routine City of Seattle concretes were also tested. Surface resistivity measurements of the several concretes were obtained over time using the State of Florida Test Method FM 5-578. Resistivity was also obtained using the Wenner four-pin test method. In addition, correlative testing was conducted using ASTM C 1212 Standard Test Method for the Electrical Indication of Concrete’s Ability to Resist Chloride Penetration – what is also known as the “Coulomb Test”. After initial screening, final mix designs were again evaluated for electrical resistance and also for resistance to drying and autogenous shrinkage. This paper discusses the several test methods employed in addition to the effects of trial mix composition.
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Jiang, Meiling, Xianyu Jin, and Nanguo Jin. "Influence of Mineral Admixture on Early-Age Concrete Cracking." In 12th Biennial International Conference on Engineering, Construction, and Operations in Challenging Environments; and Fourth NASA/ARO/ASCE Workshop on Granular Materials in Lunar and Martian Exploration. American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41096(366)341.
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Ali Ali Al-sairafi, Fares, Jin Chen, Min Wei, Yizhi Wang, and Peiqi Li. "Drying Shrinkage Characteristics of Mortar Incorporating Different Mineral Admixture." In 2nd International Conference on Intelligent Manufacturing and Materials. SCITEPRESS - Science and Technology Publications, 2018. http://dx.doi.org/10.5220/0007529502260230.
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Poongodi, K., and P. Murthi. "Evaluation of pozzolanic performance of different novel mineral admixture." In FOURTH INTERNATIONAL CONFERENCE ON ADVANCES IN PHYSICAL SCIENCES AND MATERIALS: ICAPSM 2023. AIP Publishing, 2024. http://dx.doi.org/10.1063/5.0216244.
Full textReports on the topic "Mineral Admixture"
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Baral, Aniruddha, Jeffery Roesler, and Junryu Fu. Early-age Properties of High-volume Fly Ash Concrete Mixes for Pavement: Volume 2. Illinois Center for Transportation, 2021. http://dx.doi.org/10.36501/0197-9191/21-031.
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High-volume fly ash concrete (HVFAC) is more cost-efficient, sustainable, and durable than conventional concrete. This report presents a state-of-the-art review of HVFAC properties and different fly ash characterization methods. The main challenges identified for HVFAC for pavements are its early-age properties such as air entrainment, setting time, and strength gain, which are the focus of this research. Five fly ash sources in Illinois have been repeatedly characterized through x-ray diffraction, x-ray fluorescence, and laser diffraction over time. The fly ash oxide compositions from the same source but different quarterly samples were overall consistent with most variations observed in SO3 and MgO content. The minerals present in various fly ash sources were similar over multiple quarters, with the mineral content varying. The types of carbon present in the fly ash were also characterized through x-ray photoelectron spectroscopy, loss on ignition, and foam index tests. A new computer vision–based digital foam index test was developed to automatically capture and quantify a video of the foam layer for better operator and laboratory reliability. The heat of hydration and setting times of HVFAC mixes for different cement and fly ash sources as well as chemical admixtures were investigated using an isothermal calorimeter. Class C HVFAC mixes had a higher sulfate imbalance than Class F mixes. The addition of chemical admixtures (both PCE- and lignosulfonate-based) delayed the hydration, with the delay higher for the PCE-based admixture. Both micro- and nano-limestone replacement were successful in accelerating the setting times, with nano-limestone being more effective than micro-limestone. A field test section constructed of HVFAC showed the feasibility and importance of using the noncontact ultrasound device to measure the final setting time as well as determine the saw-cutting time. Moreover, field implementation of the maturity method based on wireless thermal sensors demonstrated its viability for early opening strength, and only a few sensors with pavement depth are needed to estimate the field maturity.
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Rahman, Mohammad, Ahmed Ibrahim, and Riyadh Hindi. Bridge Decks: Mitigation of Cracking and Increased Durability—Phase III. Illinois Center for Transportation, 2020. http://dx.doi.org/10.36501/0197-9191/20-022.
Full textAbstract:
Early-age cracking in concrete decks significantly reduces the service life of bridges. This report discusses the application of various concrete mixtures that include potential early mitigation ingredients. Large-scale (7 ft × 10 ft) experimental bridge prototypes with similar restraint conditions found in actual bridges were poured with different concrete mixtures to investigate mitigation techniques. Portland cement (control), expansive Type K cement, internally cured lightweight aggregate (LWA), shrinkage-reducing admixture (SRA), and gypsum mineral were investigated as mitigating ingredients. Seven concrete mixtures were prepared by using individual ingredients as well as a combination of different ingredients. The idea behind combining different mitigating techniques was to accumulate the combined benefit from individual mitigating materials. The combined Type K cement and LWA mixture showed higher concrete expansion compared with mixtures containing Portland cement, Type K cement, LWA, and SRA in the large-scale experimental deck. Extra water provided by LWA significantly enhanced the performance of Type K cement’s initial expansion as well as caused larger total shrinkage over the drying period. A combination of Type K cement and gypsum mineral showed insignificantly higher expansion compared with the individual Type K mixture. Overall, the experimental deck containing SRA showed the least total shrinkage compared with other mixtures. Finite-element modeling was performed to evaluate and predict concrete stress-strain behavior due to shrinkage in typical bridges. A parametric study using finite-element analysis was conducted by altering the structure of the experimental deck. More restraint from internal reinforcement, less girder spacing, larger girder flange width, and more restrictive support conditions increased the concrete tensile stress and led to potential cracking in the concrete deck.