Artículos de revistas: "Concrete admixture"

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Agbi, G. G., O. Z. Tachere y H. O. Juwah. "Evaluation of the impact of chemical admixtures on the compressive strength properties of concrete". Applied Journal of Physical Science 3, n.º 1 (30 de abril de 2021): 72–80. http://dx.doi.org/10.31248/ajps2021.051.

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This study was carried out to evaluate the effect of chemical admixtures on the compressive strength of concretes. The concretes were produced with the concrete mix ratio of 1:2:4, while water to cement (w/c) ratios of 0.35, 0.4, 0.45, 0.5 and 0.55 were adopted. Different concrete mixtures were produced using two chemical admixtures (hydroxycarboxylic acid and MasterRheobuild 1100) applied at the rate of 1.3% (weight of the cement), during the production process. Laboratory results of the fine aggregate used for the concrete production showed that it was well graded met international standards. All the concretes were produced and tested in accordance to American Society for Testing and Materials (ASTM) standard procedures. Results indicated that the concrete produced with the chemical admixtures showed better concrete performances both in the fresh and hardened state. After 28 days of casting, concrete produced with MasterRheobuild 1100 admixture had the best compressive strength (32 MPa); compared with the compressive strength of the concrete produced with the hydroxycarboxylic acid admixture (28 MPa), and the control concrete samples that had compressive strength of 25 MPa. In addition, the fresh concrete produced with chemical admixtures gave a better slump than the fresh concrete produced without any chemical admixture. Likewise, hydroxycarboxylic acid admixture performs better among the two admixtures used, given a more linear relationship between the slump and water/cement ratio. These results showed the importance of chemical admixtures when higher compressive strength becomes a vital factor in structural constructions

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2

Xie, Jian Bin, Tian Chun He, Yong Ping Ai y Guo Jin Ji. "Study on the Properties of Mass Hydraulic Concrete with Admixtures of Limestone Powder and Water Quenched Iron Slag". Advanced Materials Research 255-260 (mayo de 2011): 3573–78. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.3573.

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For mass concrete with the admixtures of limestone powder and water quenched iron slag (shortly called double admixture concrete) in dam of Jinghong hydropower station located at the downstream of Lancang river in Yunnan province, the mineral composition of double admixture was analyzed in this paper. And it is also studied by materials testing and microscopic analysis methods such as laser particle analysis, scanning electron microscopy, energy spectrum analysis, X-ray diffraction analysis and thermo gravimetric-differential thermal analysis that the hydration, hydrated product and mechanism of hydration process in the system of cementing and double admixture material system. Then the mechanical, thermal and deformation properties and the durability of the concrete with double admixtures were also analyzed by experimental methods. The study results show it was theoretically feasible that adopting the double admixtures as the admixture of the mass hydraulic concrete which can be roller compacted concrete or normal concrete. And the properties of the double admixture concrete in Jinghong hydropower station meet all kind requirements.

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Gadgihalli, Vishal, Ramya, Abrar Khan, Raghavendra Prasad Dinakar y Babitha Rani. "ANALYSIS OF PROPERTIES OF CONCRETE USING HUMAN HAIR LENGTH GREATER THAN 10CENTIMETER DIPPED IN SALT WATER AS FIBER REINFORCEMNT ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 4RASM (30 de abril de 2017): 50–53. http://dx.doi.org/10.29121/granthaalayah.v5.i4rasm.2017.3368.

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Admixtures now days play a predominant role in concrete manufacturing. The admixtures ranged from blood in history to fiber reinforcement admixture. In this paper the author analyzing the properties of concrete using salt water cured and oven dried human hair whose length exceeding 10cm as fiber reinforced admixture is studied and verified by strength of ordinary Portland cement without using any admixture. Using human hair length greater than 10cm as fiber reinforcement admixture gave good percentage of increment in compressive strength and flexural strength, but as the length of the human hair increases used for concrete as fiber reinforcement admixture reduces the strength.

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4

Pazderka, Jiří. "The Crystalline Admixture Effect on Concrete and Cement Mortar Compressive Strength". Key Engineering Materials 722 (diciembre de 2016): 87–91. http://dx.doi.org/10.4028/www.scientific.net/kem.722.87.

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There have been many experimental measurements of the waterproofing ability of concrete with a crystalline admixture. For the comprehensive evaluation of crystalline admixtures, it is necessary to consider their effect on the compressive strength of concrete fck, not only their waterproofing ability. The paper describes laboratory testing which subject was the selected crystalline admixtures effect on the compressive strength of concrete fck. The results have shown that the compressive strength fck,cubeof concrete with a crystalline admixture (added in an amount of 2%) was almost identical to the specimens from concrete without admixture after 28 days. The compressive strength of the next specimens from cement mortar with a smaller amount of a crystalline admixture (1%) after the 28 days was higher than the strength of the specimens without admixtures.

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Stehlík, Michal. "ENHANCING THE DURABILITY OF CONCRETE MADE OF CONCRETE RECYCLATE BY ADDITIVES AND ADMIXTURES". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 20, n.º 2 (10 de marzo de 2014): 270–79. http://dx.doi.org/10.3846/13923730.2013.802708.

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The aim of this research is to find an optimum combination of silicate admixtures and epoxy dispersion additives which would positively influence the durability and mechanical properties of concretes made of concrete recyclate. The durability of concrete is dependent on its cover layer permeability and also on the overall permeability of concrete recyclate. The cover layer permeability was evaluated by means of three methods, namely the air permeability method TPT and two methods of measuring water permeability, GWT and ISAT. Fine silicate admixtures and dispersion additives influence the air and water permeability of concrete made of concrete recyclate in different ways. The dose of 10% of microsilica or 30% of slag or fly ash decreases the air permeability of concrete. Water permeability, on the other hand, is decreased by adding a dose of 12% of pure epoxy dispersion. As regards improving the mechanical properties of concrete made of concrete recyclate, it seems to be promising to use a combination of 30% of slag admixture or 10% of microsilica admixture with 12% of epoxy dispersion additive. However, the price of admixtures and additives is relatively high. That is why additive enhanced concretes made of concrete recyclate are intended for special purposes.

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6

Luo, Mei Fang. "Study on Effects of Concrete Admixtures on Performance of Concrete". Applied Mechanics and Materials 94-96 (septiembre de 2011): 856–59. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.856.

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Concrete admixture is a kind of addition agents, which can improve the performance of concrete. Adding a certain amount of concrete admixture can enhance the early strength, the age strength, and the anti-permeability strength of concrete. Also, concrete admixtures can improve the workability and adjust the setting time of concrete, so as to reduce the dosage of concrete and save the cost of concrete. This paper describes the types of concrete admixture and their functions, studies the functions of water reducers, and analyzes their effects to concrete, so as to improve the concrete performance and save materials in actual operation.

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Wang, Xue Fang y Jian Lan Zheng. "Influence of Compounded Mineral Admixtures on Shrinkage and Early-Age Cracking Behaviors of Concrete". Advanced Materials Research 450-451 (enero de 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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8

Zheng, Yu Xian y Xun Guo Zhu. "The Influence on the Concrete Durability in Bleed Air Performance Caused by Concrete Admixture". Advanced Materials Research 690-693 (mayo de 2013): 767–70. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.767.

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The article issued the influence on concrete durability caused by concrete admixture, based on the further study on concrete admixture bleed air performance test, and researched the influence on concrete durability caused by it. The experiments show that the admixtures of air-entraining performance improve internal pore structure of concrete and increase the compacting condition concrete. Concrete admixture also can improve the impermeability of concrete frost resistance and improve the resistance to environmental actions, and proposed concrete air content of the Dalian region suitable value.

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9

Al-obaidey, Shubbar Jawad. "The Synergic Effects of Mineral Admixtures in Ternary Blended Cement: A Review". Journal of Engineering 27, n.º 2 (1 de febrero de 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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10

Zhao, Mei Li. "The Effects of Mineral Admixture on the Compressive Strength of Concrete". Advanced Materials Research 450-451 (enero de 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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11

Xie, Li. "Influence of Mineral Admixtures on Early-Age Autogenous Shrinkage of High-Performance Concrete". Applied Mechanics and Materials 457-458 (octubre de 2013): 318–22. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.318.

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The influence rules of the mineral admixtures containing fly ash, ground slag and silica fume on the early-age autogenous shrinkage of high-performance concrete have been discussed in this paper. According to the research results, fly ash mixture can substantially decrease the early-age autogenous shrinkage of high-performance concrete, while the silica fume will increase the autogenous shrinkage. Meanwhile the influence of ground slag on autogenous shrinkage is related to its fineness and admixture amount. Generally, it is believed that when the fineness of the fly ash is higher than 4000cm2/g, the autogenous shrinkage will increase with the increasing admixture amount. The double admixture or multi-admixture of fly ash or ground slag is better for reducing the early-age autogenous shrinkage of concrete than the single-admixture. The early-age autogenous shrinkage of concrete occurs in distinctive linear dependence with the three types of mineral admixtures.

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12

Křížová, Klára y Rudolf Hela. "Effect of Combination of Admixture on the Development of Selected Properties of Concrete and their Comparison". Materials Science Forum 865 (agosto de 2016): 206–10. http://dx.doi.org/10.4028/www.scientific.net/msf.865.206.

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The paper is involved with effects of admixtures (fly ash, slag) and their combination on selected properties of ordinary concrete. The set of concrete covers seven different containing of Portland cement and approximately 10% of admixed slag and concrete with fly ash and slag contents up to 42 %. At early age of the concrete balanced values of compressive strength were obtained except the concrete with admixture combinations. And on the contrary at 28-day age the concrete with admixture combinations obtained comparable values like concrete with only one type of admixture. The compressive strength was monitored together with modulus of elasticity to 180-day age of the concrete. In the last phase the obtained values were compared with guide value where the slower development of theses parameters with applied admixtures was pointed out.

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Zhao, Mei Li, Ai Xiang Li, Lin Tong Wang y Yun Fa Chen. "The Study on Chloride Corrosion of Concrete Containing Admixture Mineral". Applied Mechanics and Materials 174-177 (mayo de 2012): 1269–72. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.1269.

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Chloride ions were harmful to the performance of the concrete.Admixture mineral had been replaced part of cement in high performance concrete to improve the durability and chloride resistance of the concrete.In this paper,the compressive strength of the concrete with admixture mineral and without admixture mineral had been measured cured after 28 days. The results had been shown that the compressive strength of the concrete without admixture mineral is lower than the one with admixture mineral after 28ds’and 56ds’ immersing in 5%NaCl solution. The quantities of electricity through the concretes with 30% admixture mineral were lower than the benchmark concretes. The current of C30 and C40 concretes with admixture mineral was lower than the benchmark concretes.The concrete with admixture mineral had been eroded lower than the one without admixture mineral.

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Gadgihalli, Vishal, Meena Y.R, Chandana y Prasad Havanje Dinakar. "ANALYSIS OF PROPERTIES OF CONCRETE USING SHEEP WOOL DIPPING IN SALT WATER AS FIBRE REINFORCEMENT ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 11 (30 de noviembre de 2017): 57–59. http://dx.doi.org/10.29121/granthaalayah.v5.i11.2017.2328.

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The use of admixtures is increasing very rapidly because concrete admixtures provide physical as well as economic benefits. These admixtures materials ranged from blood in history to recent fiber reinforcement. In this paper analysis of properties of concrete using salt water cored and oven dried sheep wool as fiber reinforced admixture was studied and verified the strength of concrete compared to ordinary Portland cements strength of different grade of concrete using sheep wool as fiber reinforcement admixtures. Using sheep wool as fiber reinforcement as concrete admixture gave good percentage of increment in both compressive strength and flexural strength of concrete, but as the grade of cement increases the percentage of increment in strength gradually reduces.

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15

Stott, D., T. Rezansoff y B. F. Sparling. "Loss of freeze–thaw durability of concrete containing accelerating admixtures". Canadian Journal of Civil Engineering 21, n.º 4 (1 de agosto de 1994): 605–13. http://dx.doi.org/10.1139/l94-062.

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Rapid freeze–thaw durability tests on air entrained concrete mixes containing a proprietary nonchloride accelerating admixture or CaCl2 show that although early age compressive strength acceleration is achieved, the freeze-thaw durability is reduced when compared with the durability of control concretes of similar mix proportions, but without accelerating admixtures. Although the compressive strength gains were accelerated in mixes containing either the proprietary accelerating admixture or CaCl2, the tensile strengths at 28 days were similar for mixes with and without the admixtures.Petrographic analyses showed air contents and air void spacing factors in concretes with accelerating admixtures, either nonchloride or CaCl2, to be similar to the air systems in the control concrete, though more air entraining agent was required with the mixes containing accelerating admixtures. Local aggregates as well as aggregates from three alternate sources were used. Test results did not show any significant differences in durability on the basis of aggregate source.As the larger reduction measured in freeze–thaw durability for concrete mixes containing either chloride or nonchloride accelerating admixtures could not be attributed to either a deficient air void system in the cured concrete or inferior aggregate, it is believed that the cause is some characteristic or a hydration product in the cement paste microstructure produced by accelerated hydration. Key words: concrete, durability, freeze–thaw testing, strength acceleration, admixtures, air void system.

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Li, Yun Feng, Yang Liu, Rong Qiang Du y Fan Ying Kong. "Effect of Steel Slag Powder on the Durability of High Performance Concrete". Advanced Materials Research 79-82 (agosto de 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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Jaskulski, Roman y Wojciech Kubissa. "Mechanical Properties and Resistance to Water Ingress of Cement Concrete Made with Non-Cyclic Alkanes". Advanced Materials Research 1054 (octubre de 2014): 58–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1054.58.

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The goal of presented research is an assessment of fundamental mechanical properties and resistance to water ingress of concrete with non-cyclic alkanes. Compressive and tensile strength, water absorption capacity and sorptivity of concrete made with and without an admixture of non-cyclic alkanes has been analysed. The paraffin enriched concretes have been made with 1% (C1F and C1C) and 3% (C3F and C3C) volume addition of paraffin wax. The paraffin wax has been used in two grades of comminution: fine (FP) in CxF concretes and coarse (CP) in CxC concretes. A significant (35%) loss of compressive strength of concretes with admixtures has been noticed and no loss in tensile strength was observed. Up to 25% of water absorption capacity reduction and irrefutable (8 times) sorptivity reduction has been also noticed, but only in the case of concrete made with admixture of FP.

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Ayub, Tehmina, Sadaqat Ullah Khan y Fareed Ahmed Memon. "Mechanical Characteristics of Hardened Concrete with Different Mineral Admixtures: A Review". Scientific World Journal 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/875082.

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The available literature identifies that the addition of mineral admixture as partial replacement of cement improves the microstructure of the concrete (i.e., porosity and pore size distribution) as well as increasing the mechanical characteristics such as drying shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity; however, no single document is available in which review and comparison of the influence of the addition of these mineral admixtures on the mechanical characteristics of the hardened pozzolanic concretes are presented. In this paper, based on the reported results in the literature, mechanical characteristics of hardened concrete partially containing mineral admixtures including fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA) are discussed and it is concluded that the content and particle size of mineral admixture are the parameters which significantly influence the mechanical properties of concrete. All mineral admixtures enhance the mechanical properties of concrete except FA and GGBS which do not show a significant effect on the strength of concrete at 28 days; however, gain in strength at later ages is considerable. Moreover, the comparison of the mechanical characteristics of different pozzolanic concretes suggests that RHA and SF are competitive.

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Zhao, Mei Li, Su Qing Wang y Ai Xiang Li. "The Study on Sulfate Resistance of Concrete Containing Admixture Mineral". Applied Mechanics and Materials 174-177 (mayo de 2012): 1265–68. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.1265.

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Admixture mineral has been replaced part of cement in high performance concrete to improve the durability and sulfate resistance of the concrete.In this paper,the compressive strength of the concretes with adimixture mineral and without admixture mineral had respectively measured after 28ds’ standard curing.Then the concretes had been immersing in NaSO4 solution and MgSO4 solution.The compressive strength of the concrete with admixture mineral and without admixture mineral has been measured after 28ds’and 56ds’ immersing in NaSO4 solution and MgSO4 solution. The concrete with admixture mineral had been eroded lower than the one without admixture mineral after 28 days and 56 days.

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Zhang, Ri Hua y Xian Jun Guo. "Experimental Study on Slag-Based Composite Admixture". Applied Mechanics and Materials 174-177 (mayo de 2012): 354–57. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.354.

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Admixture is a new material used for high-performance concrete. It is mainly used to improve the construction property and service performance and the durability of the concrete. At present, admixture is mainly made of a single component such as the slag, fly ash, silica fume, or mixed with a small amount of plaster. Different admixtures have different effects on the concrete and they have both advantages and disadvantages separately. Based on the principle of “Strength Synergistic Effect” of the composite materials, if the different kinds of admixtures are mixed into the concrete with suitable proportion, the advantages can be developed and the disadvantages will be avoided. In this study, the wide sources of admixtures such as slag, fly ash and limestone are used in the composite tests to develop a new kind of composite admixture which uses the slag as main raw material and has better performance.

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Popek, Mateusz y Łukasz Sadowski. "Effect of Selected Mineral Admixtures on Mechanical Properties of Concrete". Key Engineering Materials 728 (enero de 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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Pazderka, Jiří y Eva Hájková. "CRYSTALLINE ADMIXTURES AND THEIR EFFECT ON SELECTED PROPERTIES OF CONCRETE". Acta Polytechnica 56, n.º 4 (31 de agosto de 2016): 306–11. http://dx.doi.org/10.14311/ap.2016.56.0306.

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There have been many experimental measurements of the waterproofing ability and durability of concrete with a crystalline admixture, but some other important properties have not been reliably tested yet. The results of the tests, carried out by the authors, showed that crystalline admixtures reduce the water vapor permeability of concrete by 16-20 %. The authors also carried out the water pressure test in different time intervals, during the initial phase of cement hydration. The test results have shown that the full waterproofing effect of concrete with a crystalline admixture is available approximately on the 12th day after the concrete creation. The crystalline admixture effect on the compressive strength of concrete was also the subject of the testing. The results have shown that the compressive strength of the concrete with a crystalline admixture (added in an amount of 2 %) and the compressive strength of the specimens from concrete without admixture were almost identical after 28 days.

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Keli, Qin, Duan Yajuan y Guo Lixia. "Study on the Tensile Creep Model of the Admixture of Early-Age Concrete and Application Simulation". Open Civil Engineering Journal 9, n.º 1 (29 de octubre de 2015): 1002–6. http://dx.doi.org/10.2174/1874149501509011002.

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With respect to the recent issue related to the lack of research on tensile creep model of the admixture concrete at early age and simulation, the admixture influence function with factor of the admixture dosage was established based on composite exponential function as reference model based on existed creep rules and appropriate assumption. It has been proposed that contributing factor, c, quantitatively represented the sensitivity of concrete creep changes to the admixture and correlation between concrete creep and the admixture. The model fitting was then made after tensile creep experiment by adding different admixtures such as fly ash, slag, silica fume and polypropylene fiber in contract to reference concrete test. It indicated that the model exhibited a good fitting performance, which is practical and useful as well as readily adopted by simulation. Meanwhile, the contributing factor also demonstrated quantitatively the variation among the effect of the admixtures (fly ash, slag, silica fume and polypropylene fiber) on the tensile creep of the concrete. Finally, the model was applied to an as-built concrete project for extended simulation, the results indicated that tensile creep can effectively improve the distribution of surface tensile stress and alleviate detrimental effect due to day-night temperature differences.

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Wang, Yuan Gang, Peng Ma, Kai Jian Huang, Gao Qin Zhang y Ya Feng Hu. "Impact of Composite Mineral Admixture on Carbonization Resistance of High Performance Concrete". Advanced Materials Research 1095 (marzo de 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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Xia, Kai Quan, Wei Guo, Xue Wu Liu, Huan Liu, Zhan Guo Li y Yue Li. "Research on the Effects of Admixture on Concrete Permeability". Applied Mechanics and Materials 618 (agosto de 2014): 114–19. http://dx.doi.org/10.4028/www.scientific.net/amm.618.114.

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At present, our country norms on the permeability of concrete is mainly determined by its strength, without considering the influence of admixtures on the permeability. This paper studies the permeability of different strength concrete rules of different kinds and dosage of admixture. The results show that, the permeability of concrete is closely related to the w/b, but also it has a strong correlation with admixture dosage, the relevance between the permeability of concrete and the kinds of admixture is relatively small. The results of this paper can provide some reference value to the relevant standards of durability in our country.

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Gadgihalli, Vishal, Meena, Lohit, Raghavendra Prasad HavanjeDinakar y Babitha Rani. "ANALYSIS OF PROPERTIES OF CONCRETE USING SEA SHELLS CRUSHEDPOWDER AS ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 11 (30 de noviembre de 2017): 374–78. http://dx.doi.org/10.29121/granthaalayah.v5.i11.2017.2370.

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The tremendous increment of demand on concrete made admixture one of major component. As admixtures help in enhancement of concrete physical and chemical admixture. In this paper analysis of sea shells as chemical admixture is studied and verified the strength of concrete and temperature emitted due to chemical reaction to the normal Portland cement. As sea shells contain calcium carbonate, CaCo3 as major composition, as calcium is one major component that helps in densifying and hardening of bones in all living things. The flexural and compressive strength has gradually increased; the transmission temperature and reduction time of exothermal reaction has reduced. Hence seashell acts as great admixture.

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Alonso, M. M., R. Martínez-Gaitero, S. Gismera-Diez y F. Puertas. "PCE and BNS admixture adsorption in sands with different composition and particle size distribution". Materiales de Construcción 67, n.º 326 (24 de febrero de 2017): 121. http://dx.doi.org/10.3989/mc.2017.08116.

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The choice of a superplasticiser (SP) for concrete is of great complexity, as it is well known that properties of the end product are related to admixture and its compatibility with concrete components. Very few studies have been conducted on the compatibility between SPs and the sand of mortars and concretes, however. Practical experience has shown that sand fineness and mineralogical composition affect water demand and admixture consumption. Clay-containing sand has been found also to adsorb SPs, reducing the amount available in solution for adsorption by the cement. This study analysed the isotherms for PCE and BNS superplasticiser adsorption on four sands with different fineness and compositions commonly used to prepare mortars and concretes. BNS-based SP did not adsorb on sands, while PCE-based admixtures exhibited variable adsorption depending on different factors. The adsorption curves obtained revealed that the higher the sand fineness, the finer the particle size distribution and the higher the clay material, the greater was PCE admixture adsorption/ consumption.

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Li, Xin, Qiang Wang y Shu Hua Liu. "Activity Index of Steel Slag-GGBS Composite Mineral Admixture at Different W/B Ratios". Applied Mechanics and Materials 584-586 (julio de 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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29

Khan, Sadaqat Ullah, Muhammad Fadhil Nuruddin, Tehmina Ayub y 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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30

Gadgihalli, Vishal, Meena Y.R, Bharath A.L y Raghavendra Prasad HavanjeDinakar. "ANALYSIS OF PROPERTIES OF CONCRETE USING SAFETY MATCHES POWDER AS ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 11 (30 de noviembre de 2017): 53–56. http://dx.doi.org/10.29121/granthaalayah.v5.i11.2017.2327.

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Recently admixtures had made a major importance in the concrete manufacturing. These admixtures materials ranged from blood in the history to the recent retarding agents. In this paper analysis of properties of concrete using safety matches powder as admixture is studied and verified the strength of concrete and temperature emitted due to chemical reaction to the normal Portland cement. Using safety matches powder the temperature emitted due to exothermal reaction of concrete has reduced. This gives better results hence we can use this safety matches powder as an admixture where the reacting temperature and the emitting temperature place a crucial role in construction and maintenance.

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31

Gadgihalli, Vishal, Meena, Pallavi y Raghavendra Prasad. "ANALYSIS OF PROPERTIES OF CONCRETE USING GUM BASE DISSOLVED WATER SOLUTION AS ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 4RASM (30 de abril de 2017): 67–70. http://dx.doi.org/10.29121/granthaalayah.v5.i4rasm.2017.3372.

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Chemical admixtures are the forth ingredient of the concrete which is inevitable for the modern concretes, the properties of concrete can be modified either in plastic and the hardened state as required. In this paper analysis of properties of concrete using gum base dissolved water solution as chemical admixture is studied and verified to strength of concrete to normal Portland cement, As chewing gum is cohesive substance composed of gum base. By using gum base solution as solution the compressive strength and tensile strength of concrete has gradually increased compared to normal concrete; this indicates that the cohesion property of gum base helps in improvement of bond strength of concrete.

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32

Krishna, B. Gopal, Pooja Prasad, Vibha Sahu, Jyoti Prabha Sahu y Akansha Agarwal. "Beta Backscattering and Gamma Radiation Absorption Characteristics of Carbon Nanoparticles Contained Concrete Composite". Nano Hybrids and Composites 17 (agosto de 2017): 31–36. http://dx.doi.org/10.4028/www.scientific.net/nhc.17.31.

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Concrete is a very important composite for making different building structures to absorb different levels of radiation. Nuclear power plants, nuclear research reactors, particle accelerators and linear accelerator in medical institution use concrete in building construction. Nanoparticles or nanocrystals have different properties than their bulk counterparts. The gamma radiation absorption characteristics and beta back scattering by nanoparticles is also different than their counterparts. In this paper, carbon nanoparticles are mixed in the concrete composite during its preparation. The concrete composite with carbon nanoparticles as admixture were analyzed to provide radiation protection. The gamma radiation absorption characteristics and beta back scattering in ordinary and carbon nanoparticles contained concretes have been studied by GM counter. The results show that using carbon nanoparticles as an admixture in the concrete is one of the solutions for gamma ray shielding and beta back scattering. Therefore, it is good to use carbon nanoparticles as admixtures in concrete composites for beta and gamma radiation scattering and absorption respectively.

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33

Huang, Zhi De. "Study on High Amount Mineral Admixtures Concrete Performance". Applied Mechanics and Materials 357-360 (agosto de 2013): 667–70. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.667.

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Depended on Qingdao Bay Bridge construction, large amount mineral admixture replacing cement has been conducted systematical research aiming at marine concrete, main control index is chloride ion permeability resistance. The main research contents concrete working, mechanical properties and chloride ion permeability resistance at low water binder ratio and large amounts mineral admixture. Measures and adjustment are proposed for marine concrete construction control and cementitious material system that using amount mineral admixtures and low water binder ratio.

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34

Tang, Ying y Guo An Wang. "A Research on the Anti-Sulfate Corrosion Effects of the Concrete Mixed with Complex Multi-Mineral Admixture". Applied Mechanics and Materials 71-78 (julio de 2011): 755–59. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.755.

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This paper is focused on the method for improving capability of anti-sulfate corrosion of concrete. Based on the performance characteristics of mineral admixture, propose a method that mixing concrete with complex multi-mineral admixture to improve the effect of anti-sulfate corrosion. Finally, the ability of anti-sulfate corrosion and anti-dry-wet cycle, in different case, is studied and compared. The results show that concrete mixed with complex multi-mineral admixture is advantageous to improve the anti-sulfate corrosion effects of the concrete. The proportion of mineral admixtures has significant influence on the anti-sulfate corrosion effect. As the silica fume and slag content increased, the fly ash content decreased, the ability of anti-sulfate corrosion enhanced.

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35

Zhang, Tao, Yun Yun Xu y Lei Chen. "On the Principle and Application of Concrete Admixtures". Advanced Materials Research 557-559 (julio de 2012): 805–8. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.805.

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Widely used for concrete admixtures, the development status of concrete admixtures is summarized, the two classification methods of concrete admixtures are induced. Especially, currently mainly used four kinds of admixtures, water reducer, air entraining agents, retarders, and early strength agent, the working principle, the problem of construction application, the direction of development and construction technology are analyzed. Finally, admixture overall future direction of development prospect is presented.

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36

Gadgihalli, Vishal, Ramya, Abrar Khan y Raghavendra Prasad Dinakar. "ANALYSIS OF PROPERTIES OF CONCRETE USING POTASSIUM POWDER AS ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 4RASM (30 de abril de 2017): 41–45. http://dx.doi.org/10.29121/granthaalayah.v5.i4rasm.2017.3366.

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Chemical admixtures are the ingredients in concrete other than Portland cement, water and aggregate those are added to mix immediately before or during mixing. These admixtures are primarily used to reduce the cost of concrete construction, to modify the properties of hardened concrete, to ensure the quality of concrete during mixing, transportation, placing curing and to overcome certain emergences during concrete operations. In this paper analysis of properties of concrete using potassium power as admixture is studied and verified the strength of concrete and temperature emitted due to chemical reaction to normal Portland cement. Using potassium powder the temperature emitted due to exothermal reaction of concrete has reduced. Thus gives better results hence we can use this potassium powder as an admixture where the temperature and the emitting temperatures place a crucial role in construction and maintenance.

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37

Mohammed, Tarek Uddin, Tanvir Ahmed, Shibly Mostafiz Apurbo, Tahir Absar Mallick, Farhan Shahriar, Abdul Munim y Mohammad Abdul Awal. "Influence of Chemical Admixtures on Fresh and Hardened Properties of Prolonged Mixed Concrete". Advances in Materials Science and Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/9187627.

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Effects of different chemical admixtures on fresh and hardened properties of prolonged mixed concrete and their cost-effectiveness were investigated. Influence of sand to aggregate volume ratio, cement content, and use of chilled mixing water on the properties of prolonged mixed concrete was studied as well. Different concrete mixtures were prepared using five different types of chemical admixture (one water reducer based on lignosulfonate and four superplasticizers based on sulfonated naphthalene polymer, polycarboxylic ether, second-generation polycarboxylic ether polymer, and organic polymer), varying s/a ratio (0.40 and 0.45) and cement content (340 kg/m3 and 380 kg/m3) and using chilled mixing water. Slump tests were performed at 15-minute intervals to assess the fresh performance of each prolonged mixed concrete mixture. 100 mm by 200 mm cylindrical concrete specimens were prepared and tested for compressive strength, Young’s modulus, splitting tensile strength, and ultrasonic pulse velocity. Results indicate that concretes with sulfonated naphthalene polymer-based superplasticizer and second-generation polycarboxylic ether-based superplasticizer show best performances in both fresh and hardened states. Concrete with lignosulfonate-based water reducer exhibits poor performance in comparison with the concretes with superplasticizers. The cost per unit compressive strength of concrete with sulfonated naphthalene polymer-based superplasticizer is lower compared with the concretes with other types of chemical admixture.

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38

He, Zhi Min, Jun Zhe Liu y Tian Hong Wang. "Mechanical Properties of Steam-Cured Concrete with Combined Mineral Admixtures". Advanced Materials Research 168-170 (diciembre de 2010): 1535–38. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1535.

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In precast concrete elements manufacturing, steam-cured concrete incorprating 30% mineral admixtures encountered the problem of too low demoulding compressive strength. To resolve it, this paper mainly studied the influence of mineral admixtures on the compressive strength, the tensile-splitting strength and the flexural strength of the steam-cured concrete. The experimental results indicated that, compared with steam-cured concrete incorprating mineral admixtures, the later strength of steam-cured concrete incorprating 0% mineral admixtures has lower increment degree and its increment of tensile-splitting strength and flexural strength inverted to some extent. The demoulding compressive strength is too low for the high volume fly ash concrete mixtures. The problem of too low demoulding compressive strength is solved by incorprating composites of ground blast furnace slag(GBFS) and fly ash. Different varieties of mineral admixture used in the concretes can produce a certain degree of potentiation.

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39

Krishnaraj, L., P. T. Ravichandran, M. V.A.Karthik, N. Satheeshram Avudaiyappan y . "A Study on Porous Sealing Efficacy of hydrophilic Admixture on Blended Cement Concrete". International Journal of Engineering & Technology 7, n.º 2.12 (3 de abril de 2018): 446. http://dx.doi.org/10.14419/ijet.v7i2.12.11514.

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The life of the concrete is strongly influenced by durability parameters. The permeability is one of the main characteristics influencing the durability of concrete. The concrete is more permeable due to the ingress of water, oxygen, chloride, sulphate, and other potential deleterious substances. The durability of concrete is mainly affected by pore structure system of concrete and addingthe supplementary cementitious materials (SCM), such as fly ash, slag cement, and silica fume can be decrease permeability. Crystalline technology enhances the strength of concrete by filling the poresand micro-cracks with non-dissolvable substances. To study the efficiency of crystalline formation in concrete in terms of more permeable should be guaranteed through a specific technique.The effectiveness of crystalline waterproofing system with partial replacement cement by GGBS is studiedin terms of strength and durability. The performance of the two different types of crystalline waterproofing integral admixtures has been studied for compressive strength, Split tensile strength, workability, water permeability, Rapid chloride permeability test and porosity in this paper.The early strength increased in GGBS with crystalline admixture concretes compare to the control concrete. No significant strength reduction is observed in GGBS concretes with crystalline admixture when replaced with 20% and 40% of cement than control concrete.

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40

Gadgihalli, Vishal, Meena, Sindu y Raghavendra Prasad Dinakar. "ANALYSIS OF PROPERTIES OF CONCRETE USING STEEL FIBERS AS FIBER REINFORCEMENT ADMIXTURE". International Journal of Research -GRANTHAALAYAH 5, n.º 4RASM (30 de abril de 2017): 59–62. http://dx.doi.org/10.29121/granthaalayah.v5.i4rasm.2017.3370.

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Fiber reinforced concrete is composite material consisting of mixtures of cement, mortar or concrete, discontinuous discrete uniform dispersed suitable fibers. Fiber reinforced concrete are of different types and properties. In this paper analysis of properties of concrete using steel fibre as fiber reinforcement admixture is studied and verified the strength of concrete to normal plane concrete with absence of admixtures. Using steel fibers as fiber reinforcement admixture increases bond strength by enhancing surface tension as steel is better in taking flexural strength this gives better results, hence we can use this steel fiber reinforcement to concrete where the compressive and flexural strength place a crucial role in construction and maintenance.

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41

Makrides-Saravanos, Elli y T. Rezansoff. "The effect of a chloride-based accelerating admixture on the tensile strength of concrete". Canadian Journal of Civil Engineering 12, n.º 3 (1 de septiembre de 1985): 673–84. http://dx.doi.org/10.1139/l85-074.

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Compression and tension tests were performed on specimens made from high-early-strength concrete, where the strength acceleration was achieved by using a chloride-based accelerating admixture. Comparison with specimens made from concrete without the admixture showed that the concrete with the admixture was significantly weaker in tension for equal compressive strength.Curing times ranged from 3 days to 3 or 4 months while compressive strengths ranged from 16 to 37 MPa depending on the batch and the age at testing. Three types of tension tests, the standard split cylinder test, the standard modulus of rupture test, and a pull-out test were used in the study.Current design equations that relate tensile strength of concrete to the measured compressive strength may overestimate the actual tensile strength of high-early-strength concrete where acceleration is achieved through the addition of an admixture. These equations are found in provisions for anchorage, development, and splicing of reinforcement, shear and torsion strength, and the prediction of service load deflections. Key words: concrete, accelerated strength, tensile strength, admixtures, curing, splitting tensile strength, modulus of rupture, strength correlations.

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42

Ozyildirim, H. Celik y Harikrishnan Nair. "Durable Concrete Overlays in Two Virginia Bridges". Transportation Research Record: Journal of the Transportation Research Board 2672, n.º 27 (11 de junio de 2018): 78–87. http://dx.doi.org/10.1177/0361198118777606.

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The purpose of this study was to implement innovative concretes with low permeability and reduced cracking potential in overlays to reduce chloride infiltration into the bridge decks. Two parallel bridges on Route 64 over Dunlap Creek in Alleghany County, Virginia, were selected for this study. For low cracking potential, relatively low water contents, shrinkage reducing admixtures, and lightweight aggregates were used. For low permeability, concretes had supplementary cementitious material and relatively low water–cementitious material ratios. In the overlays, five different materials were used: latex-modified concrete with rapid set cement; silica fume concrete alone; and silica fume concrete with shrinkage reducing admixture, lightweight coarse aggregate, and partial lightweight fine aggregate. A compressive strength of 3,000 psi at 3 days was sought. The performance of the overlay concretes was observed after two to three winters. The overlays used in this study achieved the specified strength and low permeability. There were minimal tight cracks except for one section with the latex-modified concrete with rapid set cement in the left lane of the westbound bridge. The extensive cracks in that section were attributed to plastic shrinkage from adverse weather conditions at placement and the fact that a truck had caught fire in that lane. Silica fume concrete overlays with shrinkage reducing admixture, lightweight coarse aggregate, or lightweight fine aggregate are ready for implementation in the field for low cracking overlays.

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43

Feng, Xiangrui, Zhenshu Li y Anjing Ma. "Effect of polypropylene thick/basalt composite fibers on the mechanical properties of large dose slag fly ash concrete". E3S Web of Conferences 233 (2021): 03005. http://dx.doi.org/10.1051/e3sconf/202123303005.

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In this experiment, the effects of polypropylene thick fiber (PPTF) with different volume admixtures (0, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%) on the compressive strength, splitting tensile strength and bending strength of large admixture of slag fly ash concrete were investigated with short-cut basalt fiber (BF) as a reference. The results show that the polypropylene thick fiber can work well with basalt fiber and improve its strengthening effect of single admixture. And 0.10% of polypropylene thick fiber and 0.10% of basalt fibers by volume have the best strengthening effect on the mechanical properties of the large amount of slag fly ash concret.

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44

Okeniyi, Joshua Olusegun, Isaac Oluwaseun Oladele, Oluwafemi Michael Omoniyi, Cleophas Akintoye Loto y Abimbola Patricia Idowu Popoola. "Inhibition and compressive-strength performance of Na2Cr2O7 and C10H14N2Na2O8·2H2O in steel-reinforced concrete in corrosive environments". Canadian Journal of Civil Engineering 42, n.º 6 (junio de 2015): 408–16. http://dx.doi.org/10.1139/cjce-2014-0364.

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This paper studied corrosion-inhibition and compressive-strength performances of Na2Cr2O7 (sodium dichromate) and C10H14N2Na2O8·2H2O (ethylenediaminetetraacetic disodium salt: EDTA-Na2) admixtures in steel-reinforced concrete immersed in NaCl and in H2SO4 corrosive environments. Electrochemical methods were used for studying corrosion responses of different concentrations of the individual admixtures and their synergies, in the model that partially replace the toxic Na2Cr2O7 by the environmentally-friendly C10H14N2Na2O8·2H2O, in steel-reinforced concretes. After the electrochemical experiment, the steel-reinforced concrete samples were subjected to the compressive-strength testing and analyses of ASTM C39/C39M-03 and ASTM C267-01(2012). Results showed that the use of environmentally-friendly EDTA-Na2 for partially replacing toxic Na2Cr2O7 chemical exhibited better corrosion-inhibition and compressive-strength improvement in the NaCl-immersed concretes, than in the H2SO4-immersed concretes. The 2 g Na2Cr2O7 + 6 g EDTA-Na2 admixture (representing partial replacement model of 6 g Na2Cr2O7 by 6 g EDTA-Na2) exhibited optimal corrosion inhibition efficiency (η = 99.0%) and very good compressive-strength improvement advantage in the NaCl-immersed concretes. In contrast, comparatively low compressive-strength reduction trade-off with the good inhibition effectiveness of η = 79.9% support use of 6 g EDTA-Na2 admixture only (i.e., without Na2Cr2O7 addition) for inhibiting reinforcing-steel corrosion in the H2SO4-immersed concretes.

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45

Skutnik, Zdzisław, Mariusz Sobolewski y Eugeniusz Koda. "An Experimental Assessment of the Water Permeability of Concrete with a Superplasticizer and Admixtures". Materials 13, n.º 24 (10 de diciembre de 2020): 5624. http://dx.doi.org/10.3390/ma13245624.

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This study presents a flow pump technique usually used for evaluating the permeability of soils, which was, for first time, applied to measure the water permeability of concrete. Additionally, a new easy-to-apply method to determine permeability is proposed, based on a modification of Valenta’s formula. In the calculations, the apparent air content of concrete mixes was taken into account. An additional purpose of the conducted research was to determine the influence of a new generation of polycarboxylate superplasticizer and chemically active admixtures on the permeability, compressive strength, and other properties of concrete. The following four types of concrete were tested: concrete without admixtures, concrete with an admixture to increase the compressive strength, concrete with a superplasticizer, and concrete containing two admixtures simultaneously. The results showed that the proposed method allows to obtain reliable measurements within a very short period of time. The obtained results confirmed that new method may be very useful in engineering practice, particularly in terms of the watertightness of hydrotechnical concretes and the properties of the concretes used in bridge construction, underground parts of office buildings, or sealed tanks.

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46

Guo, Jinjun, Zheng Zhang, Jingjiang Wu, Huikang Wang, Peng Zhang, Kun Wang, Qingxin Meng y Hongyin Xu. "Early-Age Mechanical Characteristics and Microstructure of Concrete Containing Mineral Admixtures under the Environment of Low Humidity and Large Temperature Variation". Materials 14, n.º 17 (5 de septiembre de 2021): 5085. http://dx.doi.org/10.3390/ma14175085.

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The application of concrete containing mineral admixtures was attempted in Northwest China in this study, where the environment has the characteristics of low humidity and large temperature variation. The harsh environment was simulated by using an environmental chamber in the laboratory and four types of concrete were prepared, including ordinary concrete and three kinds of mineral admixture concretes with different contents of fly ash and blast-furnace slag. These concretes were cured in the environmental chamber according to the real curing conditions during construction. The compression strength, fracture properties, SEM images, air-void characteristics, and X-ray diffraction features were researched at the early ages of curing before 28 d. The results showed that the addition of fly ash and slag can improve the compression strength and fracture properties of concrete in the environment of low humidity and large temperature variation. The optimal mixing of mineral admixture was 10% fly ash and 20% slag by replacing the cement in concrete, which can improve the compression strength, initial fracture toughness, unstable fracture toughness, and fracture energy by 23.9%, 25.2%, 45.3%, and 22.6%, respectively, compared to ordinary concrete. Through the analysis of the microstructure of concrete, the addition of fly ash and slag can weaken the negative effects of the harsh environment of low humidity and large temperature variation on concrete microstructure and cement hydration.

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47

Jackiewicz-Rek, W., J. Kuziak y B. Jaworska. "Analysis of the Properties of Expansive Concrete With Portland and Blast Furnace Cement". Archives of Civil Engineering 64, n.º 4 (1 de diciembre de 2018): 175–96. http://dx.doi.org/10.2478/ace-2018-0051.

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AbstractThe properties of expansive concretes made of two types of cement: Portland cement CEM I and blast furnace slag cement CEM III were tested. The expansion of the concrete was caused by using an expansive admixture containing aluminium powder added in an amount of 0.5; 1 and 1.5% of cement mass. It was found that the compressive strength of concrete with CEM I decreased after using an expansive admixture in the amount of more than 0.5% of the cement mass. The compressive strength of concrete with CEM III decrease after addition of admixture in the entire range of dosages used. On the basis of electrochemical measurements, it was found no influence of an expansive admixture on corrosion of reinforcing steel. The use of an expansive admixture causes a slight increase in the effective diffusion coefficient of chloride ions in concrete.

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48

Xu, De Jin, Chuan Qing Fu, Xian Yu Jin, Ye Tian y Nan Guo Jin. "Experimental Study on Strength and Abrasion-Resistance Enhancement Admixture". Advanced Materials Research 250-253 (mayo de 2011): 247–51. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.247.

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Cement concrete has an increasing utilization in highway construction. However, the lower flexural tensile strength and abrasion-resistance restricted the development of concrete pavement with heavy traffic. Hence, It has highlighted the need for research on high performance concrete (HPC). The design of specific concrete normally depends on the mixing of mineral admixtures in concrete mixture. This paper presents the first experimental study on strength and abrasion-resistance enhancement admixture (SAEA) mixed with slag powder, steel slag powder and silica fume. The optimal proportion of three mineral admixture and reasonable mixed amount of SAEA were then given, and the mechanism of SAEA reacted in concrete was analyzed based on sol-gel theory. Lastly, the effect of concrete mixed with SAEA was validated and the micro-structure transformation of specimens was given by SEM.

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49

Marshdi, Qosai Sahib Radi, Ahlam Hamid Jasim y Haider Abass Obeed. "Effect of Dolomite as Expansive Agent and Shrinkage Reducing Admixture in Self-Compacting Shrinkage – Compensating Concrete". Journal of University of Babylon for Engineering Sciences 26, n.º 5 (6 de marzo de 2018): 1–8. http://dx.doi.org/10.29196/jub.v26i5.848.

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The principle of using expansive agents has been recommended to manufacture shrinkage compensating concrete provided that an adequate wet curing is carried out. On the other hand, shrinkage-reducing admixture (SRA) in the concrete mixes, has been more recently suggested to reduce the risk of cracking in concrete structures caused by drying shrinkage. This paper is devoted to the study of the influence of complex modifier in the form of superplasticizer, shrinkage reducing admixture and expansive agent CaO- MgO-based on the fresh properties, hardening processand restrained shrinkage of Self-Compacting-Shrinkage-Compensating Concretes. The combined addition of shrinkage-reducing admixture with expansive agent has been found to be successful in producing shrinkage-compensating concrete. It should be noted also that the shrinkage reducing admixture slightly improve the workabilityof the fresh concrete mixtures but, it slightly reduces the early compressive strength of concrete.

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50

Lee, Kwang-Myong, Su-Ho Bae, Jae-Im Park y Soon-Oh Kwon. "Mass Change Prediction Model of Concrete Subjected to Sulfate Attack". Mathematical Problems in Engineering 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/298918.

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The present study suggested a mass change prediction model for sulfate attack of concrete containing mineral admixtures through an immersion test in sulfate solutions. For this, 100% OPC as well as binary and ternary blended cement concrete specimens were manufactured by changing the types and amount of mineral admixture. The concrete specimens were immersed in fresh water, 10% sodium sulfate solution, and 10% magnesium sulfate solution, respectively, and mass change of the specimens was measured at 28, 56, 91, 182, and 365 days. The experimental results indicated that resistance of concrete containing mineral admixture against sodium sulfate attack was far greater than that of 100% OPC concrete. However, in terms of resistance against magnesium sulfate attack, concrete containing mineral admixture was lower than 100% OPC concrete due to the formation of magnesium silicate hydrate (M-S-H), the noncementitious material. Ultimately, based on the experimental results, a mass change prediction model was suggested and it was found that the prediction values using the model corresponded relatively well with the experimental results.

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