Journal articles: 'Alumina cement'

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Kotsay, Galyna, and Irmina Masztakowska. "The Effect of Fine-Ground Glass on the Hydration Process and Properties of Alumina-Cement-Based Composites." Materials 14, no. 16 (August 17, 2021): 4633. http://dx.doi.org/10.3390/ma14164633.

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This paper discusses studies regarding the impact of fine-ground glass additives on the hydration and properties of alumina cement pastes and mortars. Fine-ground glass was added to pastes and mortars instead of high-alumina cement and calcium aluminate cement in quantities of 5% and 10%. The findings are inconclusive as to the impact of glass on the properties of tested alumina cement types. The effect produced via the addition of glass instead of cement depends on the type of alumina cement used. Adding fine-ground glass to high-alumina cement enhances the paste’s density while improving paste and mortar strength. Using the same additive for calcium aluminate cement reduces its density and strength. The addition of glass to high-alumina cement adversely affects its strength at higher temperatures.

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Xia, Zhong Feng, Zhou Fu Wang, Xi Tang Wang, Hao Liu, and Yan Ma. "Effect of Micro-Sized Alumina Powder on the Hydration Process of Calcium Aluminate Cement." Solid State Phenomena 281 (August 2018): 249–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.249.

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Micro-sized alumina powder is widely used in low cement high-alumina refractory castables. The hydration of calcium aluminate cement can be affected by adding micro-sized alumina powder. This work addresses the hydration of a commercial cement at 25°C with 50 wt% micro-sized alumina powder added. The hydration heat was measured by isothermal micro-calorimetry. The phase composition and microstructure of the hydration products at the designated times were studied by XRD and SEM, respectively. The results showed that micro-sized alumina powder accelerated the dissolution of CAC. The induction period of the cement hydration reduced from 13h to 4.5h, and the hydration heat within 50hs was increased from 469J/g to 587J/g with the addition of micro-sized alumina powder. The morphology of the hydrates was flocculent amorphous at the beginning, and then transformed to short rods or cubic shape with micro-sized alumina powder added.

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Kuzin, V. I., R. V. Zubashchenko, D. A. Timoshenko, and M. A. Trubitsyn. "Production of fine-ground aluminas NK-Alumina 11 and NK-Alumina 14 for low-cement refractory castables." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 5 (November 26, 2021): 94–97. http://dx.doi.org/10.17073/1683-4518-2021-5-94-97.

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The characteristics of fine-ground aluminas NK-Alumina 11 and NK-Alumina 14, developed in JSC «PKF «NK», for low-cement refractory castables are presented. It is shown that the quality indicators of the developed aluminas are not inferior to foreign analogues.

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Angelescu, Nicolae, Cristina Stancu, Sofiane Amziane, Vasile Bratu, and Elena Valentina Stoian. "Study on Hydration and Strengthening of High Alumina Cements." Scientific Bulletin of Valahia University - Materials and Mechanics 15, no. 12 (April 25, 2017): 22–27. http://dx.doi.org/10.1515/bsmm-2017-0004.

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Abstract Refractory concretes based on aluminous cements are used with great success in areas where high temperatures are required. The mineralogical composition of the high alumina cement is the main factor which gives the physical and mechanical properties at high temperatures of refractory monolithic materials.It is therefore desirable to use high alumina cements based on mineralogical compounds with high refractoriness, because in the end those beneficial properties can be found in the final product - refractory concrete.The aim of this paper is to design, realize and characterize different compositions of high alumina cements based on mineralogical compounds with the highest refractory from the CaO-Al2O3 binary system (i.e. CA, CA2, and CA6), and to find ways of hydraulic activation of calcium hexa aluminate, also.

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Kaddo, Maria. "Possibilities of using aluminate cements in high-rise construction." E3S Web of Conferences 33 (2018): 02056. http://dx.doi.org/10.1051/e3sconf/20183302056.

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The article describes preferable ways of usage of alternative binders for high-rise construction based on aluminate cements. Possible areas of rational use of aluminate cements with the purpose of increasing the service life of materials and the adequacy of the durability of materials with the required durability of the building are analyzed. The results of the structure, shrinkage and physical and mechanical properties of concrete obtained from dry mixes on the base of aluminate cements for self-leveling floors are presented. To study the shrinkage mechanism of curing binders and to evaluate the role of evaporation of water in the development of shrinkage was undertaken experiment with simple unfilled systems: gypsum binder, portland cement and «corrosion resistant high alumina cement + gypsum». Principle possibility of binder with compensated shrinkage based on aluminate cement, gypsum and modern superplasticizers was defined, as well as cracking resistance and corrosion resistance provide durability of the composition.

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Hemanth Kumar, G., and B. Ajitha. "Prediction of Compressive Strength of Nano Alumina, Micro Alumina & Fly Ash Blended with Cement by Using Coefficient of Correlation." Asian Review of Civil Engineering 9, no. 2 (November 5, 2020): 8–11. http://dx.doi.org/10.51983/tarce-2020.9.2.2557.

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In this research study, the effect on High Strength Concrete (HSC) by partial replacement of cement with Nano alumina, micro alumina and fly ash on the mechanical properties of the concrete is studied. In this investigation the cement is replaced by 20% Fly ash, 5% micro alumina and nano alumina of different proportion i.e., 0.25%, 0.5%, 0.75%, 1% in M60 grade of concrete. It is observed that the concrete's workability is reduced by increasing the content of nano alumina from 0% to 1% and constant micro alumina particles of 5% cement (by Wt.) and fly ash of 20% cement (by wt.). The results showed that 0.75% of the combination of nano alumina, micro alumina and fly ash increases the properties of the high strength concrete. The microstructure characteristics results revealed that the Nano alumina, micro alumina and fly ash particles incorporated enhances the cement's mechanical strength properties and the voids were filled up with these materials. The present investigation is mainly focused on reliability assessment to the High Strength Concrete by using by using Karl Pearson’s correlation coefficient.

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Zhao, Jing Ming, Kyu Hong Hwang, Jong Kook Lee, and Min Cheal Kim. "Application of Magnesia-Phosphate Cement for Chromia/Alumina Castables." Applied Mechanics and Materials 268-270 (December 2012): 625–28. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.625.

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Refractory castables containing calcium aluminate cement (CAC) are widely used in a range of furnace lining applications in the iron and steel, cement, glass, ceramic, and petrochemical industries. However, magnesia-phosphate cement (MPC) based material could be a new types of cement material, with many advantages such as rapid hydration, high early strength and circumstance suitability, which has very important value and wide application. In this study, MPC was used at Chromia/Alumina castable as binder addition instead of conventional calcium aluminate cement. Meanwhile, it also explains the relationship between the micro-mechanism and performance by micro methods such as SEM. The results shows that MPC based castables have good corrosion resistance, interface adhesiveness and abrasion resistance.

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Bondarenko, N., D. Bondarenko, and E. Evtushenko. "STUDY OF THE CHEMICAL INTERACTION OF GLASS FIBER WITH CEMENT HYDRATION PRODUCTS." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, no. 12 (January 8, 2021): 119–25. http://dx.doi.org/10.34031/2071-7318-2020-5-12-119-125.

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Reinforcement of concrete with fiberglass improves the performance properties of concrete. The object of the study is fiberglass concrete, where Portland cement or alumina cement is used as a binder, and silica fiberglass is used as a filler. The chemical and phase compositions of Portland cement and alumina cement have been studied. The influence of the products of hydration of Portland cement and alumina cement on the chemical resistance of glass fiber has been investigated. The phase composition of Portland cement and alumina cement after hydration is studied using X-ray phase analysis. It is revealed that the following phases are present in alumina cement: CaОAl2O3, MgОAl2O3, 12CaO•7Al2O3, 2CaO•Al2O3•SiO, the phase composition of Portland cement is Ca6Al2(SO4)3(OH)12•12H2O, Ca2,25(Si3O7,5(OH)1,5)•(H2O), Ca(OH)2, CaCO3. It has been found that when hydrated, Portland cement has a negative effect on fiberglass due to the presence of Ca(OH)2 in it. The phase composition of the alumina cement after hydration shows the absence of Ca(OH)2. The chemical composition of fiberglass is investigated using X-ray fluorescence analysis. The use of alumina cement when using non-alkali-resistant fiberglass in a composite material is substantiated. The study of the stability of fiberglass in the environment of cement drawing has been carried out. Studies have shown that KV-11 grade fiberglass interacted less with hydration products of alumina cement than with hydration products of Portland cement.

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PAGHANDEH, M., A. MONSHI, and R. EMADI. "THE EFFECT OF FINE ALUMINA TYPE ON COMPOSITION OF IN SITU SPINEL FORMATION IN ALUMINA-MAGNESIA CASTABLES." International Journal of Modern Physics B 25, no. 27 (October 30, 2011): 3633–39. http://dx.doi.org/10.1142/s0217979211101211.

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Three types of low cement castables (LCC) were prepared from 5% reactive alumina ( R 5), 5% calcined alumina ( A 5) and equal proportions of 2.5% (AR). The nest of the composition was fine bauxite (0–1 mm, 57%), coarse bauxite (1–3 mm, 20%), calcined magnesia (5%), secar 71 refractory cemet (7%) and microsilica (1%). By the addition of 5% water, castables were moulded, aged, dried and fired to 1400°C for 2 h. XRD studies showed higher amount of in situ spinel formation in A 5. The lattice constants of spinels in A 5, AR and R 5 were, respectively, 8.0348, 8.0688 and 8.0847 Å. This accounted for respectively alumina rich, stochiometry and magnesia rich spinels. Since calcined alumina is cheaper, produce higher amounts of spinel with the aid of alumina from the aggregate of bauxite and the binder of cement, and alumina rich spinel has better corrosion resistance properties, use of calcined alumina is recommended in LCC.

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Qin, Min, Nai Xing Liang, and Zhao Feng Lu. "Performance Study on Alumina Red Mud-Cement Stabilized Macadam Base." Advanced Materials Research 250-253 (May 2011): 728–32. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.728.

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Based on the analysis of chemical constituents and mineral composition, a new disposal method of alumina red mud added in cement stabilized macadam base was put forward. Through experiments of compressive strength, dynamic elastic modulus, splitting intensity and resilient modulus, mechanical properties of alumina red mud- cement stabilized macadam base and base performance affected by alumina red mud dosage were studied. Also, the strength formation micro-mechanism of alumina red mud-cement stabilized macadam mixture was explored by scanning electron microscopy (SEM). The results indicate that alumina red mud-cement stabilized macadam mixture has good mechanical properties; its early compressive strength, early splitting intensity, dynamic elastic modulus, resilient modulus are improved obviously with alumina red mud mixing; the mixing amounts of alumina red mud and cement are significantly affected mixture strength and the optimum mixing amount is respectively 10~12% and 5~6%; alumina red mud can promote cement hydration and hydrates generation. it not only is used as interstitial material among aggregates，also as binder closely linked aggregates through the spatial reticular structure formed by red mud and cement hydrates, which enhance mixture strength.

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11

Luu Thi, Hong, Long Luong Duc, Cham Trinh Thi, Luan Ta Van, and Qui Duong Thanh. "Effects of silicafume and fly ash on properties of alumina cement." MATEC Web of Conferences 251 (2018): 01015. http://dx.doi.org/10.1051/matecconf/201825101015.

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Alumina cement which was used in this investigation contains about 56% of Al2O3 in the component. Early compressive strength alumina cement at 1 and 3 days can be achieved of 85% compressive strength value at 28 days. After a long period of hydration, the compressive strength of alumina cement harder decreased due to the releasing process of aluminum hydroxide [Al(OH)3] to the outside environment [1, 4,11]. To improve and maintain the long lasting compressive strength of alumina cement harden, new binders would be created SiO2- Al2O3 and among CaO-SiO2-Al2O3. The new binders would exist sustainably in the cement harden as a result of the chemical reaction between the product of hydrated cement called gel [Al(OH)3] with micro silica (amorphous SiO2) [4]. This report demonstrates the result of the investigation which is about the effect of silica fume and fly ash on alumina cement.

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Lewis, Jennifer A., and Waltraud M. Kriven. "Microstructure-Property Relationships in Macro-Defect-Free Cement." MRS Bulletin 18, no. 3 (March 1993): 72–77. http://dx.doi.org/10.1557/s0883769400043943.

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The term “macro-defect-free” refers to the absence of relatively large voids (or defects) that are normally present in conventional cement pastes due to entrapped air or inadequate mixing. A decade ago, Birchall and co-workers developed a novel processing method that avoids the formation of these strength-limiting defects. This method, outlined schematically in Figure 1, consists of mixing hydraulic cement powder, a water-soluble polymer, and a minimal amount of water under high shear to produce a macro-defect-free (MDF) cement composite. Several cement/polymer systems can be processed by this flexible technique, although the calcium aluminate cement/polyvinyl alcohol-acetate (PVA) copolymer system is most common: MDF cements display unique properties relative to conventional cement pastes. For example, the flexural strength of MDF cement is more than 200 MPa as compared to values on the order of 10 MPa for conventional pastes. One can view MDF cements as a type of “inorganic plastic.” As is the case with plastic processing, fillers such as alumina, silicon carbide, or metal powders can be added to MDF cement to modify its performance properties (e.g., abrasion resistance, thermal or electrical conductivity, and hardness). The combined attractiveness of inexpensive raw materials and flexible, low-temperature processing has generated great interest in this new class of advanced cement-based materials.

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Zhang, Dong Mei, and Ming Shi Lu. "Preliminary Experimental Study on Self-Leveling Ground Mortar." Applied Mechanics and Materials 357-360 (August 2013): 689–93. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.689.

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The effects of the different content of cement-sand ratio,fineness modulus of sand, heavy calcium carbonate and high alumina cement on the self-leveling mortar was studied according to orthogonal experiment.The results show that when cement-sand ratio is 1.33,fineness modulus of sand is 2.2,heavy alumina is 20%,alumina cement is 10%,the mix amount of mortar is optimum.It can get a good performance of self-leveling mortar.

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Migal’, V. P., V. V. Skurikhin, S. I. Gershkovich, O. S. Fedorova, G. V. Rusakova, and P. E. Alekseev. "High-alumina cembor cements for low-cement refractory concretes." Refractories and Industrial Ceramics 53, no. 1 (May 2012): 4–8. http://dx.doi.org/10.1007/s11148-012-9452-z.

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Parashar, Anuj, and Shashank Bishnoi. "Hydration behaviour of limestone-calcined clay and limestone-slag blends in ternary cement." RILEM Technical Letters 6 (March 19, 2021): 17–24. http://dx.doi.org/10.21809/rilemtechlett.2021.134.

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The effect of kaolinitic calcined clay and slag on the hydration of limestone-containing ternary blended cements was investigated. The effect of alumina from different sources of SCMs was considered to activate the formation of carboaluminates. Ternary blends with 50% ordinary portland cement clinker, 45% blends of limestone calcined clay (LC2) in 1:2 blend and slag limestone blend (SLS) in 2:1 mix proportion with 5% of gypsum were studied. The hydration behaviour was analysed based on cement mortar compressive strength, heat of hydration using an isothermal calorimeter and bound water measured using thermal gravimetric analysis (TGA). In addition, the degree of hydration of clinker phases and the composition of calcium - alumino - silicate - hydrate (C-A-S-H) gels forming in two different systems were compared on 90 days hydrated samples analysed using X-Ray diffractometry (XRD) and scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX) respectively. The results show a rapid early strength development in limestone calcined clay cement blend (LC3) but a lower clinker hydration in comparison with slag limestone cement blend (SLSC) at later ages. In both the cement blends the formation of hemicarboaluminate (Hc) and monocarboaluminate (Mc) was confirmed at 90 days, but the conversion of Hc to Mc was higher in SLSC. Results further confirmed a lower degree of hydration and higher alumina incorporation in the C-A-S-H gel in the LC3 comparison to SLSC. The presence of calcium hydroxide was also confirmed in the SLSC blend due to the hydraulic nature of slag that supported the later age conversion of Hc to Mc as not seen in LC3.

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Li, Jin Hong, Ling Xin Tong, and Wen Cai Zhou. "Phase Composition, Microstructure and Mechanical Properties of Aluminous Cements Containing Magnesium Aluminate Spinel." Key Engineering Materials 492 (September 2011): 467–71. http://dx.doi.org/10.4028/www.scientific.net/kem.492.467.

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A new type aluminous cement containing magnesium aluminate (MA) spinel was prepared from mixtures of limestone, magnesian and bauxite at different ratios by sintering process. The phase composition, microstructure and mechanical properties of aluminous cements containing magnesium aluminate spinel were investigated in this paper. According to the XRD results, the magnesium aluminate spinel (MA),calcium monoaluminate (CA) and calcium bialuminate (CA2) are the primary phases of the obtained aluminous cements with a small quantity of calcium silicoaluminate (C2AS) and remained alumina (Al2O3). The results of SEM indicate that the MA mainly exist in the shape of octahedron with the length of about 2-5 μm, and it is agglomerated with the tabular or flaky-shaped CA among the obtained aluminous cements. In addition, the compressive strength of castables containing obtained aluminous cements increase obviously with the content of CA rising or the curing time increasing.

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Zajac, Maciej, Jan Skocek, Jørgen Skibsted, and Mohsen Ben Haha. "CO2 mineralization of demolished concrete wastes into a supplementary cementitious material – a new CCU approach for the cement industry." RILEM Technical Letters 6 (July 15, 2021): 53–60. http://dx.doi.org/10.21809/rilemtechlett.2021.141.

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This contribution discusses the carbon capture and utilization (CCU) approach based on CO2 mineralization of cement paste from recycled concrete as new approach to capture CO2 and significantly contribute to the reduction in CO2 emissions associated with cement production. The current literature suggests that all CO2 released from the decomposition of limestone during clinker production can be sequestered by carbonation of the end-of-life cement paste. This carbonation can be achieved in a few hours at ambient temperature and pressure and with a relatively low CO2 concentration (< 10 %) in the gas. The carbonation of cement paste produces calcite and an amorphous alumina-silica gel, the latter being a pozzolanic material that can be utilized as a supplementary cementitious material. The pozzolanic reaction of the alumina-silica gel is very rapid as a result of its high specific surface and amorphous structure. Thus, composite cements containing carbonated cement paste are characterized by a rapid strength gain. The successful implementation of this CCU approach relies also on improved concrete recycling techniques and methods currently under development to separate out the cement paste fines and such. Full concrete recycling will further improve the circular utilization of cement and concrete by using recycled aggregates instead of natural deposits of aggregates. Although the feasibility of the process has already been demonstrated at the industrial scale, there are still several open questions related to optimum carbonation conditions and the performance of carbonated material in novel composite cements.

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A, Sheikh Shamim. "5741357 Hydrated high alumina cement." Cement and Concrete Composites 21, no. 3 (January 1999): 242. http://dx.doi.org/10.1016/s0958-9465(99)90114-2.

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Saeed, Dr Musab Hamed, Dr Shirin Mohammad Horr, and Dr Jamal A. Mehdi. "Evaluation of three novel retrograde filling materials (Microleakage study)." Mustansiria Dental Journal 10, no. 2 (February 26, 2018): 156–60. http://dx.doi.org/10.32828/mdj.v10i2.224.

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The aim of this study was to compare apical microleakage of MTA followingreverse retrograde root filling with that following Alumina Cement, Light Cement,Zenium HMP retrofilling. The root canals of 42 extracted teeth were instrumented andobturated with vertically condensed gutta-percha. Each tooth was apically resectedand the apex was prepared by fissure bur to 2 mm depth and the root surface isolatedwith nail varnish. Teeth were divided randomly into four groups of 10 teeth each.First group was retrofilled with MTA, second group with Alumina Cement, thirdgroup with Light Cement, and the fourth group with Zenium HMP. Followingimmersion in 2% Fuchsine dye for 72 hours, the roots were sectioned and the depth ofdye penetration was evaluated by a Global stereomicroscope at x70 magnification.Thesealing effectiveness of the retrograde filling materials was determined by their abilityto inhibit dye penetration. Results showed that the least leakage for zeniuum HMPcement with a mean of 0.6, MTA with a mean of 1.0, light cement with a mean of1.10, alumina cement with a mean of 1.50 with the most leakage. However, thesedifferences were not seen to be statistically significant using the Kruskal Wallis Testor the Mann Whitney Test. It was concluded that Zenium HMP cement provides abetter seal than MTA and Light Cement and Alumina Cement when used asretrograde filling.

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Abdullah, Muhammed, and Serwan Rafiq. "Compressive Strength of Cement Mortar Modified with Nano-Alumina in Correlation with Different Water-to-Cement Ratios and Curing Periods -A Statistical Analysis." Sulaimani Journal for Engineering Sciences 7, no. 3 (December 30, 2020): 79–98. http://dx.doi.org/10.17656/sjes.10135.

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One promising insight to extended service life of cement mortar and improve it is durability by assimilating nano mechanism into the cement-based materials. Regardless of many research studies on the effect of nano alumina on the mechanical performance of cement mortar, there has not been a widespread study examining the effect of nano Al2O3, curing period (t), and water-to-cement ratio (w/c) on the compressive strength (σc) of cement mortar. Consequently, this study explores the subject matter which could be helpful for the building and construction field. In this study, the data collected on the compressive strength of the cement mortar modified with different percentages of nano alumina ranging from 0.5% to 13.5% (by dry weight of the cement) were gathered from the literature. A nonlinear modeling NLM and statistical data analysis were performed on above 500 assembled data. The w/c ratio of the cement mortar varied from 0.3% to 0.79%, and the compressive strength of cement mortar modified with nano alumina and cured for 1,7 and 28 up to 90 days leads to high strength ranged from (10 MPa to 68 MPa). The result of NLM showed that curing period has the highest effect on the compressive strength in combination with water to cement ratio and percentage of nano alumina replacement with a coefficient of determination (R2) of 0.85.

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Abolhasani, Amirmohamad, Bijan Samali, and Fatemeh Aslani. "Physicochemical, Mineralogical, and Mechanical Properties of Calcium Aluminate Cement Concrete Exposed to Elevated Temperatures." Materials 14, no. 14 (July 9, 2021): 3855. http://dx.doi.org/10.3390/ma14143855.

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One commonly used cement type for thermal applications is CAC containing 38–40% alumina, although the postheated behavior of this cement subjected to elevated temperature has not been studied yet. Here, through extensive experimentation, the postheated mineralogical and physicochemical features of calcium aluminate cement concrete (CACC) were examined via DTA/TGA, X-ray diffraction (XRD), and scanning electron microscopy (SEM) imaging and the variation in the concrete physical features and the compressive strength deterioration with temperature rise were examined through ultrasonic pulse velocity (UPV) values. In addition, other mechanical features that were addressed were the residual tensile strength and elastic modulus. According to the XRD test results, with the temperature rise, the dehydration of the C3AH6 structure occurred, which, in turn, led to the crystallization of the monocalcium dialuminate (CA2) and alumina (Al2O3) structures. The SEM images indicated specific variations in morphology that corresponded to concrete deterioration due to heat.

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Khajornboon, Jiraprabha, Kouichiro Washijima, and Takeshi Shiono. "Fracture Energy and Fracture Toughness of In Situ Calcium Hexaluminate (CA6)-Alumina Monolithic Refractory." Key Engineering Materials 766 (April 2018): 77–82. http://dx.doi.org/10.4028/www.scientific.net/kem.766.77.

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One of main raw materials for monolithic refractory is calcium aluminate cement which provides CA6 hexagonal plate-like microstructure with self-toughening properties and fracture resistance. In the present study, in-situ CA6 was formed by using sintered alumina mixing with alumina cement in stoichiometric composition to achieve 100 mass% and 50 mass% of CA6 in alumina monolithic refractory with 2 mass% of silica addition. Samples were fired from 1400-1500°C for 5 h and characterized for physical and mechanical properties. The results showed that both samples could not obtain CA6 content as expected and apparent porosity did not exhibit in the same tendency. However, only proper amount of CA6 content could gain proper amount of apparent porosity which is the main effect of mechanical properties. Especially the formation of CA6 lower than 50 mass% with the presence of low melting phase caused low apparent porosity and led to high fracture toughness and effective fracture energy.

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Grover, Liam M., Uwe Gbureck, David Farrar, and J. E. Barralet. "Adhesion of a Novel Calcium Phosphate Cement to Cortical Bone and Several Common Biomaterials." Key Engineering Materials 309-311 (May 2006): 849–52. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.849.

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In this study, we have shown that by incorporating pyrophosphoric acid into a brushite cement system, it is possible to produce a cement that exhibits adhesive tensile strengths with cortical bone, alumina, sintered hydroxyapatite and 316L stainless steel of 700 kPa. To our knowledge, this is the first report of a calcium phosphate cement formulation that exhibits such adhesive properties without the addition of an organic additive. The production of a bond between medical prostheses and bone may further widen the field of application of calcium phosphate cements, additionally the adhesive nature of the calcium phosphate cement may be a desirable ‘handling characteristic’ during reconstructive surgery.

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Xu, Guan Li, Chuan Min Sun, Yao Sun, and Hai Liao. "A New Comprehensive Utilization Method for Coal Gangue: Preparing Alite-Sulphoaluminate Cement." Advanced Materials Research 652-654 (January 2013): 1527–32. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1527.

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Coal gangue is a kind of solid waste which is discharged from coal mining and coal washing. Dumped gangues do not only take a large land occupation but also pollute air and water. Treatment and utilizing of coal gangues has become the major issue for the coal industry to resolve. As major experimental material in this study, the coal gangue from Dawukou, Shizuishan, Ningxia province, China had been analyzed to have high-alumina content, and it could been used as alumina constituent for the preparation of sulphoaluminate cement. In this paper, alite-sulphoaluminate cements were prepared at 1330°C using coal gangue, limestone and gypsum as major main materials, fluorite and barite as minor materials. The result shows that major clinker minerals of the cement are sulphoaluminate, alite and belite, while major hydrate is ettringite, compressive strength of the cement is 48.9MPa after 7d. These experiments provide a new method of coal gangue comprehensive utilization.

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Ma, Weiping, and Paul W. Brown. "Hydration of sodium phosphate-modified high alumina cement." Journal of Materials Research 9, no. 5 (May 1994): 1291–98. http://dx.doi.org/10.1557/jmr.1994.1291.

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High strength can be achieved in high alumina cement (HAC) through the incorporation of phosphate-based additions at levels of 10 and 20 wt. %. In order to establish the mechanism that results in higher strength, the effects of a variety of condensed sodium phosphates (NaPO3)n, (NaPO3)n · Na2O, Na5P3O10, and (NaPO3)3 were studied. The influence of these additions on the kinetics of hydration was studied using isothermal calorimetry. The phosphatic additions enhanced reactivity, but x-ray diffraction analyses did not reveal evidence of new crystalline phosphate-containing hydration products. Microstructural evolution was examined in real time using environmental SEM, and hydration products exhibiting distinct morphologies were observed. The features exhibited ranged from amorphic to polygonal shapes, plates, and fibers. These frequently formed between crystalline calcium aluminate hydrate grains and by doing so appear to provide a means to enhance the strengths of these cements. In spite of the morphological variations, companion energy dispersive x-ray analysis showed that the compositions of these products did not vary widely. Their ranges of compositions are 52-60 wt. % Al2O3, 20-26 wt. % P2O5, and 20-24 wt. % CaO.

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Lee, Yunsu, Seungmin Lim, and Hanseung Lee. "Chloride Resistance of Portland Cement-Based Mortar Incorporating High Aluminate Cement and Calcium Carbonate." Materials 13, no. 2 (January 12, 2020): 359. http://dx.doi.org/10.3390/ma13020359.

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Whether chloride resistance is highly influenced by chloride binding capacity remains unknown. In this study, the chloride resistance of Portland cement-based mortar incorporating aluminate cement and calcium carbonate was investigated considering the chloride binding capacity, pore structures and chloride diffusion coefficient from non-steady state chloride migration and natural chloride diffusion. The cement hydrates were investigated using X-ray diffraction and thermogravimetric analysis. The chloride binding capacity was evaluated based on the chloride adsorption from the solutions using the adsorption isotherm. The aluminate cement, as an available alumina source, can stimulate the formulation of layered double hydroxides, which in turn can increase the chloride binding capacity. The results of mercury intrusion porosimetry show that non-substituted (control) and substituted (only aluminate cement) specimens have capillary pore volume 8.9 vol % and 8.2 vol %, respectively. However, the specimen substituted with aluminate cement and calcium carbonate shows a higher capillary volume (12.9 vol %), which correlates with the chloride diffusion coefficient. Although the specimen substituted with calcium carbonate has a higher chloride binding capacity than the control, it does not necessarily affect the decrease in the chloride diffusion coefficient. The capillary pore volume can affect not only the chloride diffusion but also the chloride adsorption.

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Hlavinková, Eva, Marcela Fridrichová, Dominik Gazdič, and Kateřina Havlíčková. "Laboratory Preparation of a Ternary Binder System." Advanced Materials Research 1000 (August 2014): 63–66. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.63.

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Currently, the binders of self-levelling mixtures are most commonly implemented as one-component or two-component (binary) systems. One-component systems are usually Portland cement or alumina cement alone, both further modified especially by plasticizers and dispersive additives. In addition to their indisputable advantages, one-component as well as binary systems have some drawbacks including worse technological properties in the case of one-component systems based on Portland cement and higher financial costs in the case of binary systems which are usually mixtures of anhydrite II and α-gypsum. These deficiencies should be addressed by a ternary system which represents a compromise between the quality and affordability of existing systems. The basis of this ternary system is Portland cement to which an expansion agent composed of alumina cement and gypsum or dry hydrate is added. In this system, it is expected that the required strength and volume stability will be provided by Portland cement and the expander, respectively. The aim of this work is to study the ternary binder system based on Portland cement, alumina cement and gypsum or supplementary non-traditional connective components for use in the industrial production of self-levelling mixtures.

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Klárová, Miroslava, Jozef Vlček, Michaela Topinková, Jiří Burda, Alexandr Martaus, Ivan Priesol, and Jacek Szczerba. "Cement Substitution in High-Temperature Concrete." Minerals 11, no. 11 (October 21, 2021): 1161. http://dx.doi.org/10.3390/min11111161.

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An alternative binder to calcium aluminate cement (CAC) was prepared by the sol-gel method. Chemically pure systems such as tetraethylorthosilicate (SiC8H20O4) and nonahydrate of alumina nitrate (Al(NO3)3·9H2O) were used as major raw materials. The manufacturing process of binder via solution is mentioned, and transitions in binder structure as a function of thermal treatment in the range between 85 and 1400 °C are described. Finally, binder efficiency was verified by its application in high-temperature concrete instead of calcium aluminate cement (CAC). Newly developed sol-gel binder was characterized by XRFS quantitative analyses, XRD diffraction, STA-DTA and TG analyses and the BET method. Samples of concrete which were based on natural bauxite raw material showed cold compressive strength of 42 MPa compared to the same material where a conventional CAC was applied, and samples reached cold compressive strength of 44 MPa.

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Hellmig, R. J., and H. Ferkel. "Using Alumina Nanopowder as Cement in Bonding of Alumina Ceramics." physica status solidi (a) 175, no. 2 (October 1999): 549–53. http://dx.doi.org/10.1002/(sici)1521-396x(199910)175:2<549::aid-pssa549>3.0.co;2-#.

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Zaldat, G. I., and E. V. Zalizovskii. "High-alumina cement for refractory concretes." Refractories 27, no. 7-8 (July 1986): 444–48. http://dx.doi.org/10.1007/bf01389514.

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Pratt, P. L. "High alumina cement concrete in construction." Structural Survey 9, no. 3 (March 1991): 261–67. http://dx.doi.org/10.1108/02630809110031556.

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Savina, L. K., I. V. Khonchyk, P. O. Kuschenko, and I. G. Shulyk. "Investigation on the influence of quartz-containing additives type on the properties of castable samples from a low-cement alumina-silica castable before and after thermal treatment." Scientific research on refractories and technical ceramics 121 (December 30, 2021): 86–93. http://dx.doi.org/10.35857/2663-3566.121.09.

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Ensuring compliance of the physical and mechanical properties of castable products with differentiated operating requirements is achieved by optimizing the grain size composition of the fireclay aggregate, using a microfiller with an increased content of aluminum oxide and reactive additives in the matrix component, choosing effective deflocculants and plasticizers additives, etc. The influence of aggregate type, its grain size composition, quartzcontaining additives (quartz-containing additive FS or a mixture of combined grinding of ɑ-form alumina and quartz-containing additive S), amount of cement grade of “VGTs-73” on water demand, flowability of freshly prepared mass and properties of castable samples from low-cement alumina-silica castable after thermal treatment at temperatures of 110, 800 and 1400 °C. It was found that, with a partial replacement of fireclay in the castable with brown alumina, an addition introduction of ɑ-form alumina and a quartzcontaining component, an increase in the amount of high-alumina cement grade of “VGTs-73” from 5 to 8 %, the water demand decreases and the castable flowability increases, the strength of castable samples increases before and after thermal treatment. As a result of the carried out research, a technology for the manufacture of low-cement alumina-silica castable with Al2O3 content 52—56 % has been developed and mastered in JSC “URIR named after A. S. Berezhnoy”.

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Jia, Quan Li, Yu Cui Zhang, and Fang Bao Ye. "Effect of Additives on the Expansion Behavior of Alumina-Spinel Castables." Advanced Materials Research 399-401 (November 2011): 62–65. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.62.

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Alumina–spinel castables were prepared using tabular alumina and coarse spinel as aggregates, calcium aluminate cement, fused alumina fines, spinel fines and ultrafine alumina as matrixes. Effect of microsilica and dispersant on the properties of alumina–spinel castables were investigated in this paper. The results show that with the same content of microsilica addition, the values of permanent linear change and apparent porosity of samples with different additives fired at 1500°C and 1600°C are noticeably increased. The maximum expansion value is 2.01%, 1.47% and 2.59%, respectively, for Sample B (additive: FS 10), Sample E (additive: sodium tripolyphosphate) and Sample F (additive: sodium tripolyphosphate +H3BO3). There is a decrease in the final expansion value with the soaking time increases, which is associated to the sintering shrinkage of the castables in this temperature range under a compression load of 0.2 MPa, Expansion behavior of alumina–spinel castables is much different with different additive addition due to abrupt CA6 crystal growth.

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Ez-zaki, H., A. Diouri, M. Maher, A. Aidi, and T. Guedira. "Effect of mechanical activation of fly ash added to Moroccan Portland cement." MATEC Web of Conferences 149 (2018): 01074. http://dx.doi.org/10.1051/matecconf/201814901074.

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Nowadays, the cement industry is the largest emitter of CO2. In 2015, cement production accounts for roughly 8% of global CO2 emissions. In order to reduce this impact, cement plants are working on alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement. This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.

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OSBORNE, G. J. "BRECEM: A RAPID HARDENING CEMENT BASED ON HIGH ALUMINA CEMENT." Proceedings of the Institution of Civil Engineers - Structures and Buildings 104, no. 1 (February 1994): 93–100. http://dx.doi.org/10.1680/istbu.1994.25683.

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Qin, Yan, Guo Tao Liu, Ze Ming Tong, and Yong Chen. "Development and Application of Shotcreting Castable for Steel Ladle." Advanced Materials Research 396-398 (November 2011): 848–53. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.848.

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The article mainly introduct the development and application of shotcreting castable for metallurgical steel ladle. The shotcreting castable mainly use tabular alumina, white fused corundum, fused spinel, aluminate cement, alumina micro powder, fused magnesium as raw material, After studied by the workability and physical properties of gunning machine, it is proved by application in steel ladle, the shotcreting castable has a good workability, with higher adhesive rate, faster hardening speed, better thermal shock resistance and stronger erosion resistance ability. So the shotcreting castable has a higher service life.

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Jongprateep, Oratai, Prawin Laomorakot, and Krongkarn Sirinunwatana. "Composition and Microstructure of Cement-Like Materials Synthesized by Solution Combustion Technique." Advanced Materials Research 1044-1045 (October 2014): 16–22. http://dx.doi.org/10.4028/www.scientific.net/amr.1044-1045.16.

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Massive production of Portland cement through mining process imposes detrimental effects on environment. Utilization of industrial and agricultural wastes as alternative raw materials for cement production, thus, has a pronounced positive impact on human quality of life. This study aimed at synthesizing constituents that exist in Portland cement by the solution combustion technique. Cockleshell, rice husk ash, and alumina wastes were used as initial reagents for the synthesis. Compositional analysis of the synthesized powders exhibited desired phases of dicalcium silicate, tricalcium silicate, and tricalcium aluminate. Compositional and microstructural analyses of the specimens cast from combusted powders revealed similar features compared with Portland cement. Ettringite, calcium hydroxide, and calcium silicate hydrate were prominent phases observed from both compositional and microstructural analyses.

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Nagrockienė, Džigita, Giedrius Girskas, Gintautas Skripkiūnas, and Aurelijus Daugėla. "PROPERTIES OF CONCRETE MODIFIED BY AMORPHOUS ALUMINA SILICATE." Engineering Structures and Technologies 6, no. 4 (March 27, 2015): 178–83. http://dx.doi.org/10.3846/2029882x.2015.1016314.

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Concrete is the most widely used building material obtained by hardening the mix made of coarse and fine aggregates, cement as the binding material, and water. The basic properties of concrete depend on the quality and properties of cement, w/c ratio and the homogeneity of compaction. Compressive strength is one of the most important properties of concrete. Materials used: Portland cement CEM I 42.5 R, 0/4 fraction sand, 4/16 fraction gravel, amorphous alumina silicate admixture, polycarboxylate ether-based superplasticizer Muraplast FK 63.30, and tap water. Five compositions of concrete mixes containing 0%, 2.5%, 5%, 7.5% and 10% of amorphous alumina silicate admixture by mass of cement were produced. The article analyses the effect of amorphous alumina silicate on the properties of concrete depending on the admixture content. The results revealed that the compressive strength of concrete after 7 days of curing increased by 7.1%, after 28 days of curing increased by 13.3% when the amorphous aluminum oxide doped silicate content was increased to 10%. Amorphous alumina silicate admixture added in quantities of up to 10%, increased the density of hardened concrete by 0.75%, and ultrasonic pulse velocity in specimens with the admixture increased up to 2.63%.

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Badalyan, Maria, Amalya Karapetyan, and Hovsep Hoveyan. "Physical-Chemical Studies of the Process of Condensation of a Clinker-Free Binder." Key Engineering Materials 906 (January 11, 2022): 47–52. http://dx.doi.org/10.4028/www.scientific.net/kem.906.47.

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The possibility of using a clinker-free binder as an alternative to expensive and energy-intensive Portland cement is being considered. The pozzolanizing effect of volcanic rocks is presented, where along with the binding of calcium hydroxide by silica to hydrosilicates, the binding of calcium hydroxide by “free” alumina to hydroaluminates also takes place. In the process of hardening of the clinker-free binder, the phase mineralogical composition of the formed new formations differs from the new formations that are synthesized during hardening of traditional Portland cement, which explains the difference in their properties. The new formations that are formed during the hardening process of clinker-free cements are mainly low-basic hydrosilicates, and alkaline aluminosilicates give the cast-in-place stone water resistance, frost resistance, waterproofing, etc., in a word, durability. Physical and chemical studies of the hardening process of clinker-free lime-igneous cements have been carried out, which indicates the possibility of replacing the energy-intensive Portland cement with cheaper clinker-free cement.

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Wei, Jun Cong, Shu Xian Liu, Hui Min Zhang, Li Xue Yu, and Jun Bo Tu. "Research and Application of Corundum Based Self-Flowing Castable Refractories." Advanced Materials Research 690-693 (May 2013): 877–80. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.877.

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The effects of different deflocculants, fume silica, reactive micro-alumina powder and high alumina cement on the flowability of corundum based self-flowing castables were investigated using brown corundum as the main starting materials. The behavior of the castables was evaluated according to the self-flow value of the castables. The results showed that the best self-flow characteristics of corundum based self-flowing castables is obtained using sodium hexametaphosphate as deflocculant, suitable amount of alumina micropowder, fume silica, and high alumina cement as binders. The resultant castables were successfully used in the bottom of a refining ladle with capacity of 80 tons. The service life could match that of well blocks and meet the production requirements.

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41

Pundiene, I., I. Prantskevichiene, M. Kligis, A. Kairite, and G. Girskas. "The influence of the cenosprehes addition on the heat-resistant lightweight ceramics." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 9 (December 29, 2018): 52–57. http://dx.doi.org/10.17073/1683-4518-2018-9-52-57.

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The investigating results are given for the cenosphere (the coal combustion wastes) inﬂuence on the alumina cement hydration and on the exothermic reaction parameters. It was established that the cenosphere content's increasing inhibits the cement hydration, decreases the samples density to 40 % after sintering at1200 °C, as well as it reduces the strength to 60 %, and the shrinkage to 95 % comparing to the reference samples. Judging by the strength to density ratio the optimum quantity of cenospheres in the alumina cement composition is 5‒10 %.Ill.7. Ref. 19. Tab. 2.

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42

Moradi, Zohreh, Farnoosh Akbari, and Sara Valizadeh. "Effects of Universal Adhesive on Shear Bond Strength of Resin Cement to Zirconia Ceramic with Different Surface Treatments." International Journal of Dentistry 2021 (June 17, 2021): 1–6. http://dx.doi.org/10.1155/2021/5517382.

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Aim. This study aimed to assess shear bond strength (SBS) of resin cement to zirconia ceramic with different surface treatments by using Single Bond Universal. Methods. In this in vitro study, 50 zirconia discs (2 × 6 mm) were divided into 5 groups of (I) sandblasting with silica-coated alumina (CoJet) + silane + Single Bond 2, (II) sandblasting with CoJet + Single Bond Universal, (III) sandblasting with alumina + Single Bond Universal, (IV) sandblasting with alumina + Z-Prime Plus, and (V) Single Bond Universal with no surface treatment. Resin cement was applied in plastic tubes (3 × 5 mm2), and after 10,000 thermal cycles, the SBS was measured by a universal testing machine. The mode of failure was determined under a stereomicroscope at × 40 magnification. Data were analyzed using one-way ANOVA. Results. The maximum (6.56 ± 4.29 MPa) and minimum (1.94 ± 1.96 MPa) SBS values were noted in groups III and I, respectively. Group III had the highest frequency of mixed failure (60%). Group V had the maximum frequency of adhesive failure (100%). Conclusion. Single Bond Universal + sandblasting with alumina or silica-coated alumina particles is an acceptable method to provide a strong SBS between resin cement and zirconia.

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Dahhou, M., R. Barbach, and M. El Moussaouiti. "Alumina sludge's Influence on the physicochemical characteristics of CPJ55 cement." MATEC Web of Conferences 149 (2018): 01058. http://dx.doi.org/10.1051/matecconf/201814901058.

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Partial replacement of the Portland cement CPJ55 ingredients by various quantities of alumina sludge (AS), produced during drinking water plant sludge, was used in the preparation of mortar mold with dimensions 40×40×160 mm. The characterization of materials is carried out by X-ray fluorescence (XRF), Xray diffraction (XRD), free lime dosing, and the mechanical tests. Analysis of the chemical composition by XRF shows that the studied alumina sludge is mainly composed of aluminum oxide, silica, which is correlated with the principal mineral phases identified in the XRD analysis results. It is demonstrated that adding 5% of the alumina sludge in Portland cement does not affect the mineralogy of final product. Nevertheless, the compression and flexural strength tests (in 28 days) conducted on mortar sample comprising 5% sludge elucidate that it belongs to cement mortar class of type 32.5 R.

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Sikora, Pawel, Didier Lootens, Maxime Liard, and Dietmar Stephan. "The effects of seawater and nanosilica on the performance of blended cements and composites." Applied Nanoscience 10, no. 12 (March 9, 2020): 5009–26. http://dx.doi.org/10.1007/s13204-020-01328-8.

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AbstractThis study investigates the effects of seawater and nanosilica (3% by weight of cement), on the fresh and hardened properties of cement pastes and mortars produced with two types of low heat cements: Portland pozzolana cement (CEM II) and blast furnace cement (CEM III). The heat of hydration, initial and final setting times, rheological properties, strength development, sorptivity and water accessible porosity of the cement pastes and mortars were determined. The data reveal that cement type has a significant effect on the reaction rate of cement with seawater and nanosilica (NS). Specimens produced with slag-blended cement exhibited a higher cement reaction rate and the composite produced exhibited better mechanical performance, as a result of the additional reaction of alumina rich phases in slag, with seawater. Replacement of freshwater with seawater contributes mostly to a significant improvement of early strength. However, in the case of slag-blended cement, 28 day strength also improved. The incorporation of NS results in additional acceleration of hydration processes, as well as to a decrease in cement setting time. In contrast, the addition of NS results in a noticeable increment in the yield-stress of pastes, with this effect being pronounced when NS is mixed along with seawater. Moreover, the use of seawater and NS has a beneficial effect on microstructure refinement, thus improving the transport properties of cement mortars. Overall, the study has showed that both seawater and NS can be successfully used to accelerate the hydration process of low heat blended cements and to improve the mechanical and transport properties of cement-based composites.

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Guirado, F., S. Galí, and S. Chinchón. "Quantitative Phase Analysis of High Alumina Cement." Materials Science Forum 378-381 (October 2001): 690–95. http://dx.doi.org/10.4028/www.scientific.net/msf.378-381.690.

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Dobrosmyslov, S. S., E. V. Peresypkin, A. S. Voronin, Y. V. Fadeev, and S. V. Khartov. "Reinforcement of cement mortar with alumina nanofibers." Journal of Physics: Conference Series 1679 (November 2020): 042096. http://dx.doi.org/10.1088/1742-6596/1679/4/042096.

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47

Sokolov, A. N., R. M. Shumeiko, L. M. Myznikova, P. D. Orekhov, and L. A. Krasnitskaya. "Production of high-alumina cement by sintering." Refractories 26, no. 1-2 (January 1985): 92–93. http://dx.doi.org/10.1007/bf01398625.

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48

Guirado, F., S. Galı́, and J. S. Chinchón. "Thermal Decomposition of Hydrated Alumina Cement (CAH10)." Cement and Concrete Research 28, no. 3 (March 1998): 381–90. http://dx.doi.org/10.1016/s0008-8846(98)00007-6.

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Dunster, Andrew, and Ian Holton. "Assessment of ageing high alumina cement concrete." Structural Survey 18, no. 1 (March 2000): 16–21. http://dx.doi.org/10.1108/02630800010322454.

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Gan, Yan Ling, Su Ping Cui, Xiao Yu Ma, and Ya Li Wang. "Effect of Silica-Alumina Ratio of Catalysts on NO Decomposition Rate in Cement Kiln Exhaust." Materials Science Forum 993 (May 2020): 1450–55. http://dx.doi.org/10.4028/www.scientific.net/msf.993.1450.

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In order to deal with the pollution of NO in cement kiln exhaust, the study of NO catalytic decomposition catalyst obtained much more attention. The effect of silica-alumina ratio on NO decomposition rate in cement kiln without other reductant was studied. The NO decomposition rate of catalysts with different silica-alumina ratio was determined by infrared spectrometer. And pore structures and the microstructure of the catalyst were characterized separately by BET surface area, nitrogen adsorption-desorption and XRD. The results show that silica-alumina ratio of catalyst was preferred to be 50 with the best NO decomposition rate when the temperature was below 300 °C. The catalyst with silica-alumina ratio of 60 has the higher catalytic activity when the temperature was higher than 300 °C, and the decomposition rate achieved 70% at 600 °C. XRD results shows the crystallinity of catalysts increased as the silica-alumina ratio increased. BET surface area and the cumulative pore volume of catalysts gradually increased, and the average pore diameter gradually reduced with the increase of silica-alumina ratio.

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Journal articles on the topic 'Alumina cement'

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