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Kavussi, Amir, Fereidoon Moghadas Nejad, and Amir Modarres. "LABORATORY FATIGUE MODELS FOR RECYCLED MIXES WITH POZZOLANIC CEMENT AND BITUMEN EMULSION / PUCOLANINIO CEMENTO IR BITUMINIŲ EMULSIJŲ MIŠINIŲ PERDIRBIMO LABORATORINIAI NUOVARGIO MODELIAI." Journal of Civil Engineering and Management 17, no. 1 (April 13, 2011): 98–107. http://dx.doi.org/10.3846/13923730.2011.553990.
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In recent years, due to technical and economical advantages, the production of pozzolanic cements have considerably extended. In the case of asphalt recycling, using Pozzolonic cements has several advantages. Lower initial stiffness and less shrinkage microcracks than Ordinary Portland Cement (OPC) are some benefits of pozzolanic cements which may reduce the probability of occuring premature cracking in recycled layer. In this reserach in order to investigate the effects of I (PM) pozzolanic cement on the fatigue cracking of recycled mixes with bitumen emulsion and develope fatigue models for these mixes, extensive indirect tensile fatigue and resilient modulus tests were performed at different temperatures and curing times. Test results showed that at high strain levels I (PM) cement specimens have superior fatigue behavior than OPC specimens. Furthermore, the effects of I (PM) cement on fatigue life of recycled mixes related to the initial strain level. Therefore a boundary strain level was determined. Above the boundary strain level, adding cement caused a reduction in fatigue life, whereas below that level the reverse was true. Finally based on laboratory testing results distinct models were established for different boundary strain levels. Santrauka Pastaraisiais metais dėl techninių ir ekonominių veiksnių pucolaninio cemento gamyba gerokai padidėjo. Pucolaninio cemento naudojimas perdirbant asfaltą turi keletą pranašumų. Mažesnis pradinis standumas ir mažiau mikroįtrūkių nei įprastame portlandcementyje (Ordinary Portland Cement, OPC) – tai keletas pucolaninio cemento pranašumų, galinčių sumažinti priešlaikinio plyšių atsiradimo tikimybę perdirbamame sluoksnyje. Šiuo moksliniu tyrimu siekiama ištirti I (PM) pucolaninio cemento poveikį nuovargio plyšių atsiradimui perdirbamuose bituminių emulsijų mišiniuose ir sukurti šių mišinių nuovargio modelius. Buvo atlikti išplėstiniai netiesioginio tempimo nuovargio ir elastingumo modulių bandymai, esant skirtingoms temperatūroms ir džiūvimo laikui. Bandymų rezultatai parodė, kad esant aukštam įtempimo lygiui I(PM) cemento bandiniai yra atsparesni nuovargiui nei portlandcemenčio (Ordinary Portland Cement, OPC) bandiniai. Be to, perdirbtų mišinių iš I (PM) cemento tvarumas yra artimas pirminiam įtempimo lygiui. Todėl buvo nustatytas ribinis įtempimo lygis. Viršijus ribinį įtempimo lygį ir įmaišius cemento tvarumas sumažėja, o esant žemesniam įtempimo lygiui buvo gautas priešingas rezultatas. Galiausiai remiantis tyrimais buvo nustatyti atskiri modeliai skirtingiems ribiniams įtempimo lygiams.
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Badrian, Hamid, Mahmoud Sabouhi, Saeid Nosouhian, Amin Davoudi, Farzaneh Nourbakhshian, and Fatemeh Naderi Nabe. "The Effect of Eugenol-Free Temporary Cement's Remnants on Retention of Full Metal Crowns: Comparative Study." Journal of Contemporary Dental Practice 14, no. 3 (2013): 473–77. http://dx.doi.org/10.5005/jp-journals-10024-1347.
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ABSTRACT Introduction The aim of this study was to evaluate the effects of eugenol-free temporary cement's remnants on the retentive strength of full metal crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. Materials and methods Forty complete standardized Ni-Cr crowns in four groups were cemented by two types of permanent cements: zinc phosphate cement and resin cement (Maxcem). In the two groups before permanent cementation of crowns, temporary acrylic crowns were cemented by eugenol-free temporary cement. Crowns¡¦ retention was evaluated by Universal testing machine. All data were analyzed by means of one-way ANOVA test in SPSS software version 11.5 (α = 0.05). Results There was no significant difference in groups with prior using eugenol-free temporary cement and groups with just using two permanents cement (p-value ≥ 0.05). Discussion The application of temporary cement before permanent cementation of full metal crowns does not have any adverse effect on retention of full metal crowns, when temporary cements are removed properly. How to cite this article Sabouhi M, Nosouhian S, Davoudi A, Nourbakhshian F, Badrian H, Nabe FN. The Effect of Eugenol- Free Temporary Cement's Remnants on Retention of Full Metal Crowns: Comparative Study. J Contemp Dent Pract 2013; 14(3):473-477.
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Sanduo, T. "The Special Features of Cement Standards in China." Cement, Concrete, and Aggregates 15, no. 2 (January 1, 1993): 165–69. http://dx.doi.org/10.1520/cca10604j.
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Abstract A large amount of blended cement, special cement, and shaft kiln manufactured cement is produced in China. These cements form the basis for China's cement standards. These standards have many special features and constitute a unique cement standard system. The standard cements are divided into three groups: common cement, special performance cement, and special purpose cement. As common cements, which include ordinary portland cement, portland blast-furnace cement, portland pozzolana cement, and portland composite slag cement, etc., the required and allowable blended materials incorporated in their specifications are somewhat like those in the European cement standard EN V 197, but some kinds of metallurgical slags are allowed into composite portland cement to make good use of industrial wastes, and a series of strength grades (including type R, which have higher early strength criteria) are stipulated for satisfying the various technical level of cement production and the different construction requirements. As to the special performance cement group, there are several series of cements such as portland cement, aluminatc cement, sulfo-aluminate cement, and ferro-aluminate cement, etc. The specifications for these cements are characteristic of their performance requirements: moderate-heat portland cement stipulates the criteria for heat of hydration; rapid-hardening aluminate cement defines criteria for strength within three days; expansive sulfo-aluminate cement requires criteria for rate of expansion; and self-stressing ferro-aluminate cements need criteria for self-stressing values, etc. In addition, oil well cement and masonry cement, etc., belong in the special purpose cement group. A graphical standards system is presented which includes fundamental standards, product standards, and test method standards. Owing to the different strength of the test methods, the cement strength value cannot be compared between different countries. The author suggests an international cooperative test program be organized for establishing the interrelation of mortar strength between different testing methods and the ISO method to facilitate international trade and to exchange information.
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Portella, Fernando Freitas, Fabrício Mezzomo Collares, Paula Dapper Santos, Cláudia Sartori, Everton Wegner, Vicente Castelo Branco Leitune, and Susana Maria Werner Samuel. "Glycerol Salicylate-based Pulp-Capping Material Containing Portland Cement." Brazilian Dental Journal 26, no. 4 (August 2015): 357–62. http://dx.doi.org/10.1590/0103-6440201300218.
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<p>The purpose of this study was to evaluate the water sorption, solubility, pH and ability to diffuse into dentin of a glycerol salicylate-based, pulp-capping cement in comparison to a conventional calcium hydroxide-based pulp capping material (Hydcal). An experimental cement was developed containing 60% glycerol salicylate resin, 10% methyl salicylate, 25% calcium hydroxide and 5% Portland cement. Water sorption and solubility were determined based on mass changes in the samples before and after the immersion in distilled water for 7 days. Material discs were stored in distilled water for 24 h, 7 days and 28 days, and a digital pHmeter was used to measure the pH of water. The cement's ability to diffuse into bovine dentin was assessed by Raman spectroscopy. The glycerol salicylate-based cement presented higher water sorption and lower solubility than Hydcal. The pH of water used to store the samples increased for both cements, reaching 12.59±0.06 and 12.54±0.05 after 7 days, for Hydcal and glycerol salicylate-based cements, respectively. Both cements were able to turn alkaline the medium at 24 h and sustain its alkalinity after 28 days. Hydcal exhibited an intense diffusion into dentin up to 40 µm deep, and the glycerol salicylate-based cement penetrated 20 µm. The experimental glycerol salicylate-based cement presents good sorption, solubility, ability to alkalize the surrounding tissues and diffusion into dentin to be used as pulp capping material.</p>
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Tkaczewska, Ewelina. "The influence of cement kiln by-pass dust addition on the properties of Portland and slag cement." Cement Wapno Beton 26, no. 1 (2021): 24–34. http://dx.doi.org/10.32047/cwb.2021.26.1.3.
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In this paper, the infl uence of cement kiln by-pass dust on the properties of Portland cement and slag cement was studied. The reference cements used in the experiment were CEM I 42.5R and CEM III/A 42.5N. The cement kiln by-pass dust replacement of cement was 0.7% and 1.7%, to satisfy the Cl- ions content in cements: lower than or equal to 0.1%, following the demand of PN-EN 197-1:2012 standard. The following properties of cements were examined: the heat of hydration, water demand for normal consistency, initial setting time and compressive strength. The results showed that the addition of cement kiln by-pass dust of up to 1.7% has no negative effect on the properties of Portland cement and slag cement. The cements represent the same strength class, as without dust addition.
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Garg, Pooja, Malesh Pujari, D. R. Prithviraj, and Sumit Khare. "Retentiveness of Various Luting Agents Used With Implant-Supported Prosthesis: An In Vitro Study." Journal of Oral Implantology 40, no. 6 (December 1, 2014): 649–54. http://dx.doi.org/10.1563/aaid-joi-d-12-00008.
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Desired retrievability of cemented implant-supported fixed prosthesis makes the retentive strength of cementing agents an important consideration. The aim of the study was to evaluate the retentiveness of purposely designed implant cement and compare its retentiveness with dental cements that are commonly used with implant systems. Ten implant analogs were embedded in auto-polymerizing acrylic resin blocks and titanium abutments were attached to them. Fifty standardized copings were waxed directly on the abutment and casted. The cements used were: (1) resin-bonded zinc oxide eugenol cement, (2) purposely designed implant cement, (3) zinc phosphate cement, (4) zinc polycarboxylate cement, and (5) glass ionomer cement. After cementation, each sample was subjected to a pull-out test using universal testing machine and loads required to remove the crowns were recorded. The mean values and standard deviations of cement failure loads were analyzed using ANOVA and Bonferroni test. The mean values (± SD) of loads at failure (n = 10) for various cements were as follows (N): resin-bonded zinc oxide eugenol cement 394.62 (± 9.76), Premier implant cement 333.86 (± 18.91), zinc phosphate cement 629.30 (± 20.65), zinc polycarboxylate cement 810.08 (± 11.52), and glass ionomer cement 750.17 (± 13.78). The results do not suggest that one cement type is better than another, but they do provide a ranking order of the cements regarding their ability to retain the prosthesis and facilitate easy retrievability.
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Abnelia-Rivera, Rosa, Domingo Alfonso Martín, and Miguel Ángel Sanjuán. "Cementos portland ternarios elaborados con escoria granulada de alto horno molida y cenizas volantes de carbón: desempeño de resistencia a la compresión = Ternary portland cements made with ground granulated blast-furnace slag and coal fly ash: compressive strength performance." Anales de Edificación 7, no. 3 (December 31, 2021): 7–9. http://dx.doi.org/10.20868/ade.2021.4969.
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Se informó que la producción mundial de cemento Portland fue de 4650 millones de toneladas en 2016. Dicha producción de cemento exige una cantidad significativa de recursos naturales y energía. Además, la producción de una tonelada de cemento Portland emite alrededor de 0,87 toneladas de dióxido de carbono. Este valor se reduciría significativamente al utilizar cementos ternarios elaborados con residuos industriales como escoria granulada de alto horno molida (GGBFS) y cenizas volantes de carbón (CFA). Además, se promueve la economía circular mediante el uso de residuos industriales (GGBFS y CFA) y se aumenta la durabilidad del hormigón en ambientes agresivos. Por el contrario, inducen un retraso en la ganancia de resistencia a la compresión como resultado de la reacción puzolánica. En este trabajo se ensayaron mezclas ternarias de cemento con proporciones GGBFS y CFA (25% y 40%) sobre morteros estándar. En consecuencia, se realizaron medidas de resistencia a la compresión a los 2, 7 y 28 días. Se discutieron las interacciones estadísticas entre GGBFS y CFA en los resultados de resistencia a la compresión de los morteros de cemento Portland ternarios.AbstractGlobal production of Portland cement was reported to be 4.65 billion tons in 2016. Such cement production demands a significant amount of natural resources and energy. Furthermore, the production of one tonne of Portland cement emits about 0.87 tons of carbon dioxide. This value would be reduced significantly by using ternary cements made with industrial wastes such as ground granulated blast-furnace slag (GGBFS) and coal fly ash (CFA). In addition, circular economy is promoted by using industrial wastes (GGBFS and CFA) and the concrete durability in aggressive environments is increased. By contrast, they induce a delay in the compressive strength gain as result of the pozzolanic reaction. In this paper, ternary cement mixes with GGBFS and CFA proportions (25% and 40%) were tested on standard mortars. Accordingly, compressive strength measures at 2, 7 and 28 days was performed. Statistical interactions between GGBFS and CFA on the compressive strength results of ternary Portland cement mortars were discussed.
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Thomas, Mathew, Mohammed Mustafa, Reshma Karkera, AP Nirmal Raj, Lijo Isaac, and R. Naveen Reddy. "Comparison of the Solubility of Conventional Luting Cements with that of the Polyacid Modified Composite Luting Cement and Resin-modified Glass Ionomer Cement." Journal of Contemporary Dental Practice 17, no. 12 (2016): 1016–21. http://dx.doi.org/10.5005/jp-journals-10024-1974.
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ABSTRACT Introduction This study was planned to find the solubility of the conventional luting cements in comparison with that of the polyacid-modified composite luting cement and recently introduced resin-modified glass ionomer cement (RMGIC) with exposure to water at early stages of mixing. Materials and methods An in vitro study of the solubility of the following five commercially available luting cements, viz., glass ionomer cement (GIC) (Fuji I, GC), zinc phosphate (Elite 100, GC), polyacid-modified resin cement (PMCR) (Principle, Dentsply), polycarboxylate cement (PC) (Poly - F, Dentsply), RMGIC (Vitremer, 3M), was conducted. For each of these groups of cements, three resin holders were prepared containing two circular cavities of 5 mm diameter and 2 mm depth. All the cements to be studied were mixed in 30 seconds and then placed in the prepared cavities in the resin cement holder for 30 seconds. Results From all of the observed luting cements, PMCR cement had shown the lowest mean loss of substance at all immersion times and RMGIC showed the highest mean loss of substance at all immersion times in water from 2 to 8 minutes. The solubility of cements decreased by 38% for GIC, 33% for ZnPO4, 50% for PMCR, 29% for PC, and 17% for RMGIC. Conclusion The PMCR cement (Principle-Dentsply) had shown lowest solubility to water at the given time intervals of immersion. This was followed by PC, zinc phosphate, and GIC to various time intervals of immersion. How to cite this article Karkera R, Nirmal Raj AP, Isaac L, Mustafa M, Reddy RN, Thomas M. Comparison of the Solubility of Conventional Luting Cements with that of the Polyacid Modified Composite Luting Cement and Resin-modified Glass Ionomer Cement. J Contemp Dent Pract 2016;17(12):1016-1021.
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Gbureck, U., J. E. Barralet, M. P. Hofmann, and R. Thulĺ. "Nanocrystalline Tetracalcium Phosphate Cement." Journal of Dental Research 83, no. 5 (May 2004): 425–28. http://dx.doi.org/10.1177/154405910408300514.
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Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on the mechanical properties of the cement was investigated. X-ray diffraction data were used to determine the phase composition of the set cements. An accelerated in vitro test compared pH of water after prolonged boiling of nanocrystalline TTCP cements and a calcium salicylate material. As milling time increased, cement compressive strength and degree of conversion increased. Hydroxyl ion release from the cement was comparable with that from a calcium salicylate material. This new cement system offers the antimicrobial potential of calcium salicylate materials combined with the long-term stability of insoluble apatite cements.
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Reis, José Maurício dos Santos Nunes, Érica Gouveia Jorge, João Gustavo Rabelo Ribeiro, Ligia Antunes Pereira Pinelli, Filipe de Oliveira Abi-Rached, and Mário Tanomaru-Filho. "Radiopacity Evaluation of Contemporary Luting Cements by Digitization of Images." ISRN Dentistry 2012 (September 13, 2012): 1–5. http://dx.doi.org/10.5402/2012/704246.
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Objective. The aim of this study was to evaluate the radiopacity of two conventional cements (Zinc Cement and Ketac Cem Easymix), one resin-modified glass ionomer cement (RelyX Luting 2) and six resin cements (Multilink, Bistite II DC, RelyX ARC, Fill Magic Dual Cement, Enforce and Panavia F) by digitization of images. Methods. Five disc-shaped specimens ( mm) were made for each material, according to ISO 4049. After setting of the cements, radiographs were made using occlusal films and a graduated aluminum stepwedge varying from 1.0 to 16 mm in thickness. The radiographs were digitized, and the radiopacity of the cements was compared with the aluminum stepwedge using the software VIXWIN-2000. Data (mmAl) were submitted to one-way ANOVA and Tukey's test (). Results. The Zinc Cement was the most radiopaque material tested (). The resin cements presented higher radiopacity () than the conventional (Ketac Cem Easymix) or resin-modified glass ionomer (RelyX Luting 2) cements, except for the Fill Magic Dual Cement and Enforce. The Multilink presented the highest radiopacity () among the resin cements. Conclusion. The glass ionomer-based cements (Ketac Cem Easymix and RelyX Luting 2) and the resin cements (Fill Magic Dual Cement and Enforce) showed lower radiopacity values than the minimum recommended by the ISO standard.
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Aghyarian, Shant, Lucas C. Rodriguez, Jonathan Chari, Elizabeth Bentley, Victor Kosmopoulos, Isador H. Lieberman, and Danieli C. Rodrigues. "Characterization of a new composite PMMA-HA/Brushite bone cement for spinal augmentation." Journal of Biomaterials Applications 29, no. 5 (August 1, 2014): 688–98. http://dx.doi.org/10.1177/0885328214544770.
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Calcium phosphate fillers have been shown to increase cement osteoconductivity, but have caused drawbacks in cement properties. Hydroxyapatite and Brushite were introduced in an acrylic two-solution cement at varying concentrations. Novel composite bone cements were developed and characterized using rheology, injectability, and mechanical tests. It was hypothesized that the ample swelling time allowed by the premixed two-solution cement would enable thorough dispersion of the additives in the solutions, resulting in no detrimental effects after polymerization. The addition of Hydroxyapatite and Brushite both caused an increase in cement viscosity; however, these cements exhibited high shear-thinning, which facilitated injection. In gel point studies, the composite cements showed no detectable change in gel point time compared to an all-acrylic control cement. Hydroxyapatite and Brushite composite cements were observed to have high mechanical strengths even at high loads of calcium phosphate fillers. These cements showed an average compressive strength of 85 MPa and flexural strength of 65 MPa. A calcium phosphate-containing cement exhibiting a combination of high viscosity, pseudoplasticity and high mechanical strength can provide the essential bioactivity factor for osseointegration without sacrificing load-bearing capability.
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Frías, Moisés, Manuel Monasterio, and Jaime Moreno-Juez. "Physical and Mechanical Behavior of New Ternary and Hybrid Eco-Cements Made from Construction and Demolition Waste." Materials 16, no. 8 (April 14, 2023): 3093. http://dx.doi.org/10.3390/ma16083093.
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Construction and demolition waste (CDW) currently constitutes a waste stream with growing potential use as a secondary raw material in the manufacture of eco-cements that offer smaller carbon footprints and less clinker content than conventional cements. This study analyzes the physical and mechanical properties of two different cement types, ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement, and the synergy between them. These cements are manufactured with different types of CDW (fine fractions of concrete, glass and gypsum) and are intended for new technological applications in the construction sector. This paper addresses the chemical, physical, and mineralogical characterization of the starting materials, as well as the physical (water demand, setting time, soundness, water absorption by capillary action, heat of hydration, and microporosity) and mechanical behavior of the 11 cements selected, including the two reference cements (OPC and commercial CSA). From the analyses obtained, it should be noted that the addition of CDW to the cement matrix does not modify the amount of water by capillarity with respect to OPC cement, except for Labo CSA cement which increases by 15.7%, the calorimetric behavior of the mortars is different depending on the type of ternary and hybrid cement, and the mechanical resistance of the analysed mortars decreases. The results obtained show the favorable behavior of the ternary and hybrid cements made with this CDW. Despite the variations observed in the different types of cement, they all comply with the current standards applicable to commercial cements and open up a new opportunity to improve sustainability in the construction sector.
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Kirgiz, Mehmet Serkan. "Chemical Properties of Substituted and Blended Cements." Advanced Materials Research 749 (August 2013): 477–82. http://dx.doi.org/10.4028/www.scientific.net/amr.749.477.
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The aim of the experimental study is to determine chemical properties of substituted and blended cement contained marble and brick powders to provide efficacy for the economical and the environmental aspect. Marble and brick powders, CEM I 42.5N cement and clinker were used as materials in the study. Substituted cements were prepared with the addition of cement for marble or brick powder at the ratios of % 6, 20, 21, 35. Blended cements were mixed the addition of cement clinker for marble or brick powder at the ratios of % 6, 20, 21, 35. And CEM I 42.5N cements were also chosen as Reference cement. Results show that marble and brick powders can prevalently add as substitute or blend materials to cement to prevent it detrimental chemicals like alkali-silica reaction.
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Funk, G., E. Horn, K. Kilway, A. Parrales, T. Iwakuma, and T. McIff. "A NOVEL SILORANE-BASED BONE CEMENT FOR LOCAL DELIVERY OF CHEMOTHERAPY AGENTS." Orthopaedic Proceedings 105-B, SUPP_8 (April 11, 2023): 94. http://dx.doi.org/10.1302/1358-992x.2023.8.094.
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Osteosarcoma and other types of bone cancers often require bone resection, and backfill with cement. A novel silorane-based cement without PMMA's drawbacks, previously developed for dental applications, has been reformulated for orthopedic use. The aim of this study is to assess each cement's ability to elute doxorubicin, maintain its potency, and maintain suitable weight-bearing strength.The silorane-based epoxy cement was synthesized using a platinum-based Lamoreaux's catalyst. Four groups of cement were prepared. Two PMMA groups, one without any additives, one with 200 mg of doxorubicin. Two silorane groups: one without any additive, one with doxorubicin, added so that the w% of drug into both cements were equal. Pellets 6 × 12 mm were used for testing (ASTM F451). n=10. Ten pellets from each group were kept dry. All others were placed into tubes containing 2.5 mL of PBS and stored at 37 °C. Elution from doxorubicin-containing groups were collected every day for 7 days, with daily PBS changeout. Antibiotic concentrations were determined via HPLC. Compressive strength and compressive modulus of all groups were determined for unsoaked specimens, and those soaked for 7 and 14 days. MTT assays were done using an MG63 osteosarcoma cell line.Both cements were able to elute doxorubicin over 7 days in clinically-favorable quantities. For PMMA samples, the incorporation of doxorubicin was shown to significantly affect the compressive strength and modulus of the samples (p<0.01). Incorporation of doxorubicin into silorane had no significant effect on either (p>.05). MTT assays indicated that doxorubicin incorporated into the silorane cement maintained its effectiveness whereas that into PMMA did not. At the dosing used, both cements remained above the 70 MPa.Both PMMA and silorane-based cements can deliver doxorubicin. Doxorubicin, however, interacts chemically with PMMA, inhibiting polymerization and lowering the chemotherapeutic's effectiveness.
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Cahyanto, Arief, Kanji Tsuru, Kunio Ishikawa, and Masanori Kikuchi. "Mechanical Strength Improvement of Apatite Cement Using Hydroxyapatite/Collagen Nanocomposite." Key Engineering Materials 720 (November 2016): 167–72. http://dx.doi.org/10.4028/www.scientific.net/kem.720.167.
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The combination of tetracalcium phosphate (TTCP; Ca4(PO4)2O) and dicalcium phosphate anhydrous (DCPA; CaHPO4) which are known as one system of apatite cements already used in the medical and dental application. In spite of several advantages of apatite cements, such as self-setting ability and biocompatibility, their mechanical strengths are still low. The aim of this study is to improve the mechanical strength of the TTCP-DCPA apatite cement using the hydroxyapatite/collagen nanocomposite (HAp/Col). The apatite cement powder was prepared using an equimolar TTCP and DCPA with addition of 10% and 20% of the HAp/Col. That without the HAp/Col was used as a control group. Each group was mixed with 1 mol/L Na1.8H1.2PO4 aqueous solution at powder/liquid ratio of 0.5 and hardened at 37°C and 100 % of relative humidity for 24 hours. A setting time of the cement was evaluated using Vicat needle according to ISO 1566 for dental zinc phosphate cements. Morphology of the cements set were observed by the scanning electron microscopy (SEM), and crystalline phases were identified by the powder X-Ray diffractometry (XRD). The mechanical strength of the cement set was evaluated by the diametral tensile strength (DTS). The setting times of cements were the shortest for the cement with HAp/Col and the longest for the control. XRD patterns of the cement at 24 hours after mixing revealed that all cements changed into apatite from the mixture of TTCP and DCPA. The DTSs of cements were the highest for the cement with 20% HAp/Col and the lowest for the control with significant differences between the cement with 20 % HAp/Col and respective other two cements. The scanning electron micrographs of the surface and fracture surface of the cements suggested that the cement with HAp/Col showed denser structure in comparison to the control and the HAp/Col fibers and/or sheets covered the fracture surface. The HAp/Col would act as reinforcement fibers as well as an adhesive of apatite granules formed by the reaction between TTCP and DCPA. The setting time and mechanical strength of apatite cement was statistically significant improved by adding 20% HAp/Col.
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McDonald, Lewis, Fredrik Glasser, and Mohammed Imbabi. "A New, Carbon-Negative Precipitated Calcium Carbonate Admixture (PCC-A) for Low Carbon Portland Cements." Materials 12, no. 4 (February 13, 2019): 554. http://dx.doi.org/10.3390/ma12040554.
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The production of Portland cement accounts for approximately 7% of global anthropogenic CO2 emissions. Carbon CAPture and CONversion (CAPCON) technology under development by the authors allows for new methods to be developed to offset these emissions. Carbon-negative Precipitated Calcium Carbonate (PCC), produced from CO2 emissions, can be used as a means of offsetting the carbon footprint of cement production while potentially providing benefits to cement hydration, workability, durability and strength. In this paper, we present preliminary test results obtained for the mechanical and chemical properties of a new class of PCC blended Portland cements. These initial findings have shown that these cements behave differently from commonly used Portland cement and Portland limestone cement, which have been well documented to improve workability and the rate of hydration. The strength of blended Portland cements incorporating carbon-negative PCC Admixture (PCC-A) has been found to exceed that of the reference baseline—Ordinary Portland Cement (OPC). The reduction of the cement clinker factor, when using carbon-negative PCC-A, and the observed increase in compressive strength and the associated reduction in member size can reduce the carbon footprint of blended Portland cements by more than 25%.
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Cui, Xu, Chengcheng Huang, Meng Zhang, Changshun Ruan, Songlin Peng, Li Li, Wenlong Liu, et al. "Enhanced osteointegration of poly(methylmethacrylate) bone cements by incorporating strontium-containing borate bioactive glass." Journal of The Royal Society Interface 14, no. 131 (June 2017): 20161057. http://dx.doi.org/10.1098/rsif.2016.1057.
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Although poly(methylmethacrylate) (PMMA) cements are widely used in orthopaedics, they have numerous drawbacks. This study aimed to improve their bioactivity and osseointegration by incorporating strontium-containing borate bioactive glass (SrBG) as the reinforcement phase and bioactive filler of PMMA cement. The prepared SrBG/PMMA composite cements showed significantly decreased polymerization temperature when compared with PMMA and retained properties of appropriate setting time and high mechanical strength. The bioactivity of SrBG/PMMA composite cements was confirmed in vitro , evidenced by ion release (Ca, P, B and Sr) from SrBG particles. The cellular responses of MC3T3-E1 cells in vitro demonstrated that SrBG incorporation could promote adhesion, migration, proliferation and collagen secretion of cells. Furthermore, our in vivo investigation revealed that SrBG/PMMA composite cements presented better osseointegration than PMMA bone cement. SrBG in the composite cement could stimulate new-bone formation around the interface between the composite cement and host bone at eight and 12 weeks post-implantation, whereas PMMA bone cement only stimulated development of an intervening connective tissue layer. Consequently, the SrBG/PMMA composite cement may be a better alternative to PMMA cement in clinical applications and has promising orthopaedic applications by minimal invasive surgery.
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McInnes-Ledoux, P. M., W. R. Ledoux, and R. Weinberg. "A Bond Strength Study of Luted Castable Ceramic Restorations." Journal of Dental Research 68, no. 5 (May 1989): 823–25. http://dx.doi.org/10.1177/00220345890680051401.
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Accurate intra coronal castings can be produced using a castable ceramic-DICOR®-for which there is a need to identify a suitable luting cement. The aim of this investigation was to evaluate the bond strength of three glass-ionomer luting cements and one resin cement to treated and untreated DICOR®, enamel, and dentin surfaces. Forty "cerammed" DICOR® specimens were assigned to four groups: (1-3) grit-blasting and bonding to each of the three glass-ionomer cements; and (4) acid-etching, silane coating, and bonding to the resin cement. Seventy enamel specimens were assigned to seven groups: (1-3) no etching and bonding to each of the glass-ionomer cements; (4-7) acid-etching and bonding to the glass-ionomer cements and the resin cement. Seventy dentin specimens were assigned to seven groups: (1-4) bonding to each of the three glass-ionomer cements and the resin cement; (5-7) polyacrylic acid preconditioning and bonding to each of the three glass-ionomer cements. The mean resin cement bond strengths (MN/m 2) to DICOR® (9.4) and to etched enamel (10.7) were significantly greater (p<0.01) than those of the glass-ionomer cements (DI-COR®, 0.8-1.2 ; enamel, 0.4-0.9). Preconditioning of enamel and dentin significantly increased (p<0.05) the bond strengths to the glass-ionomer cements. The mean bond strength of the resin cement to untreated dentin (4.3) was significantly higher (p<0.05) than the glass-ionomer bond strengths to untreated dentin (1. 0-1.7) and to preconditioned dentin (2.1-3.3). The high bond strengths achieved with the resin cement are encouraging. Selected surface treatment of DICOR®, enamel, and dentin prior to luting should be clinically useful.
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Cheday Gurung, Karma, Parminder Dua, Ritu Mangla, Neha a, Divya Sharma, and Ridhima b. "EVALUATION OF STAINLESS-STEEL CROWN CEMENTED WITH GLASS IONOMER CEMENT, RESIN MODIFIED GLASS IONOMER CEMENT AND NEW SELF-ADHESIVE RESIN CEMENT: AN INVITRO STUDY." International Journal of Advanced Research 12, no. 04 (April 30, 2024): 1031–36. http://dx.doi.org/10.21474/ijar01/18643.
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Aim: To assess and compare the retentive strength of stainless-steel crown cemented with glass ionomer cement (GC Fuji I), resin modiifed glass ionomer cement (Relyx Luting 2) and new self-adhesive resin cement (RelyX U200). Materials and Method: Forty-five extracted primary teeth were mounted on acrylic blocks. Stainless steel crowns were selected for each tooth. Three cements compared in this in vitro study were glass ionomer cement (GC Fuji I), resin modified glass ionomer cement (RelyX Luting2) and self-adhesive resin cement (RelyX U200). Teeth were randomly divided into three groups of 15 samples each. Retentive strength was tested using Instron Universal testing machine. The retentive strength values were recorded and calculated by the formula: Load/Area. Results: RelyX U200 (Self-adhesive resin cement) showed significantly higher retentive strength than rest of the two cements. No significant difference was found between RelyX Luting 2 (Resin modified glass ionomer cement) and GC Fuji I (Glass ionomer cement). Conclusion: The finding of our study suggests that self-adhesive resin cement was better than resin modified glass ionomer cement and glass ionomer cement. RelyX U200 (Self-adhesive resin cement) can be used for the cementation of stainless-steel crowns.
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Shafiei, Fereshteh, Mahtab Memarpour, and Zahra Jowkar. "Effect of Silver Antibacterial Agents on Bond Strength of Fiber Posts to Root Dentin." Brazilian Dental Journal 31, no. 4 (August 2020): 409–16. http://dx.doi.org/10.1590/0103-6440202003300.
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Abstract This study was conducted to evaluate whether antibacterial pretreatment irrigation with silver nanoparticles (SNPs) and silver diamine fluoride (SDF) has any effect on bond strength of fiber posts cemented with three types of resin cements in root canal space. Fifty-four endodontically treated maxillary central incisor roots were prepared for fiber post (FRC Postec Plus NO.3, Ivoclar Vivadent) cementation and divided into nine groups in terms of three cement types and two pretreatments with silver antibacterial agents. The cements were as follows: an etch-and-rinse cement (ER, Excite DSC/Variolink N), a self-etch cement (SE, ED Primer/Panavia F2.0), and a self-adhesive cement (SA, Panavia SA Luting Plus). For each cement, the control group was with no treatment and two experimental groups were with SNPs and SDF treatments that were used after acid-etching for ER cement and after EDTA treatment for SE and SA cements. After fiber post cementation, each bonded root was horizontally sectioned into 1-mm thickness microslices to create two slices for each root region (apical, middle and coronal) and underwent push-out bond strength (PBS) test. Data in MPa were analyzed with two-way ANOVA and Tukey test (p=0.05). The interaction of the pretreatment type and cement type was significant (p<0.001). SNPs and SDF significantly increased PBS with ER cement (p≤0.04). This positive effect was also marginally significant for SDF with SE cement (p=0.049). For SA cement, SNPs showed a significant positive effect, but SDF had a significant adverse effect on PBS (p<0.001). The effect of pretreatment with silver antibacterial agents prior to adhesive cementation of fiber posts depends on the resin cement used. Contrary to SNPs with beneficial or no significant effect on bonding for all cements, SDF exhibited a deleterious effect with self-adhesive cement.
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Kropyvnytska, Тetiana, Iryna Нeviuk, Roksolana Stekhna, Oksana Rykhlitska, and Lidiia Deschenko. "EFFECT OF LIMESTONE POWDER ON THE PROPERTIES OF BLENDED РORTLAND CEMENTS." Theory and Building Practice 2021, no. 1 (June 22, 2021): 35–41. http://dx.doi.org/10.23939/jtbp2021.01.035.
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The article shows the relation between sustainability and cement manufacture that can be obtained by the replacement of clinker with limestone additive. This decreases the use of energy resources and reduces CO2 emissions in cement production. The issue of partial Portland cement clinker substitution by finely ground limestone in the production of market-oriented types of cement type CEM II is solved on the cement plant PJSC "Ivano-Frankivsk Cement". The indexes of physical-mechanical tests of certified Portland limestone cement with high early strength CEM II/A-LL 42.5 R produced by PJSC "Ivano-Frankivsk Cement" are given. Finely dispersed limestone in Portland-composite cements with slag promotes a more complete synergic effect. It is established, that rapid-hardening blended Portland cements with limestone powder provide technological, technical, ecological, and economic effects in the production of prefabricated and monolithic reinforced concrete.
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Khalyushev, A. K., and E. A. Kolesnichenko. "“Caking” Process in Green Cement Composites under the Impact of Environment." Modern Trends in Construction, Urban and Territorial Planning 3, no. 4 (January 7, 2025): 74–81. https://doi.org/10.23947/2949-1835-2024-3-4-74-81.
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Introduction. The problems of resource and energy saving during production of cements and concretes on their basis are of great importance in the world. An important trend in solving these problems is the development of green cements, which contain various mineral additives of natural and anthropogenic origin. The advantages of the green cements compared to the clinker-based cements are revealed from both the environmental point of view — reduction of carbon dioxide emissions into the atmosphere, use of the industrial by-products, and the technical point of view — improvement of the technological properties of concrete mixes, improvement of the physical, mechanical and operational properties of con[1]cretes. At the same time, replacement of the clinker component in Portland cement by the mineral components leads to the change of the physical and mechanical properties of cement, including that taking place during the “caking” process in conditions of interaction with the environment. The research presented in the paper aims at studying the effect of long-term storage of plain cements and green cement composites in conditions of free interaction with the environment on the physical and mechanical properties of the cement stone.Materials and Methods. Various types of cements were used in the experiments. Green cement composites were obtained in the laboratory by intergrinding with the slag and fly-ash respectively. To improve the grinding process and inhibit the sorption process, a grinding intensifying agent was added into the composition of green cement composites. The impact of the environment on the cement sorption process was assessed by measuring indirect parameters: specific surface area, angle of natural repose, bulk density and cement stone compressive strength.Results. The obtained results indicate that the specific surface area of cement samples stored in the open air for 30 days reduces significantly due to the “caking” process, on average by 25% in type I cements, whereas in green cement composites this process is less intense and amounts to 15%. A similar consistent pattern is observed when measuring the angle of repose and bulk density. The decrease in the angle of repose and high values of bulk density for type I cement are related to the active sorption of moisture from the environment, which leads to the formation of hydrate “bridges” upon interaction of particles. Compared to the control samples, the compressive strength in the cement stone samples tested at the age of 28 days of curing decreases on average by 25–30% in type I cements and by a less extent of 15–20% in green cement composites.Discussion and Conclusion. When storing different types of cement in conditions of free interaction with the environment, moisture is sorbed and the hydrate “bridges” are formed on the surface of the particles. This process goes more intensely in type I cement due to the highly active surfaces of its particles, which hydrate faster, resulting in a decrease of cement activity by 30%. At the same time, the green cement composites lose their activity less significantly – by 20%. This consistent pattern can be explained by the less active surfaces of the particles of mineral additives included into the composition, as well as by addition of a grinding intensifying agent into a composition.
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Kim, Deok Yong, Nona Aryan, Nathaniel C. Lawson, and Kyounga Cheon. "Comparison of Luting Cement Solubility: A Narrative Review." Dentistry Journal 12, no. 11 (November 15, 2024): 365. http://dx.doi.org/10.3390/dj12110365.
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Background: Dental restoration success relies on the physical properties of luting cements. Luting cements fill the space between teeth and the restoration, provide retention and protection from occlusal forces, and act as a barrier to microleakages in the oral environment. Objective: This review aims to evaluate and compare the solubility of the three most used dental luting cements: glass ionomer (GI), resin-modified glass ionomer (RMGI), and resin cement (RC). Methods: The studies selected for review compared the solubilities of combinations of GI, RMGI, and RC in solutions with different pH levels to replicate acidic oral pH. Results: A review of the studies concluded that resin cement had the overall lowest degree of solubility at all pH values and all storage periods, followed by RMGI and GI cement. Conclusion: The success of the restoration is dependent upon the choice of luting cement. The results of the studies reviewed show that all dental luting cements showed some degree of dissolution. Resin cement overall demonstrated the least amount of solubility, followed by RMGI and GI cement.
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Cai, Bi Ya, Jin Hong Li, Hong Wen Ma, and Xiao Qian Jiang. "Hydration Kinetics of Aluminate Cement Containing Magnesium Aluminate Spinel." Advanced Materials Research 295-297 (July 2011): 945–48. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.945.
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The hydration heat of aluminate cement containing magnesium aluminate spinel (MA-spinel) and Commercial Lafarge cement are studied. The results show that five stages exist in the hydration processes of both cements, e.g. pre-induction, induction, acceleration, deceleration and stabilization stage. TheNvalues of the two cements are both lower than 1 in acceleration stage, on the contary higher than 1 in stabilization stage. As a result, the hydration is mainly controlled by nucleation reaction and diffusion process in acceleration stage and stabilization stage respectively. The hydration heat of aluminate cement containing MA-spinel is lower than Lafarge cement. Accordingly, the hydration rate of aluminate cement containing MA-spinel is slower than that of Lafarge cement.
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Hata, Kentaro, Yuya Komagata, Yuki Nagamatsu, Chihiro Masaki, Ryuji Hosokawa, and Hiroshi Ikeda. "Bond Strength of Sandblasted PEEK with Dental Methyl Methacrylate-Based Cement or Composite-Based Resin Cement." Polymers 15, no. 8 (April 9, 2023): 1830. http://dx.doi.org/10.3390/polym15081830.
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Poly-ether-ether-ketone (PEEK) is commonly employed in dental prostheses owing to its excellent mechanical properties; however, it is limited by its low bond strength with dental resin cement. This study aimed to clarify the type of resin cement most suitable for bonding to PEEK: methyl methacrylate (MMA)-based resin cement or composite-based resin cement. For this purpose, two MMA-based resin cements (Super-Bond EX and MULTIBOND II) and five composite-based resin cements (Block HC Cem, RelyX Universal Resin Cement, G-CEM LinkForce, Panavia V5, and Multilink Automix) were used in combination with appropriate adhesive primers. A PEEK block (SHOFU PEEK) was initially cut, polished, and sandblasted with alumina. The sandblasted PEEK was then bonded to resin cement with adhesive primer according to the manufacturer’s instructions. The resulting specimens were immersed in water at 37 °C for 24 h, followed by thermocycling. Subsequently, the tensile bond strengths (TBSs) of the specimens were measured; the TBSs of the composite-based resin cements after thermocycling were found to be zero (G-CEM LinkForce, Panavia V5, and Multilink Automix), 0.03 ± 0.04 (RelyX Universal Resin Cement), or 1.6 ± 2.7 (Block HC Cem), whereas those of Super-Bond and MULTIBOND were 11.9 ± 2.6 and 4.8 ± 2.3 MPa, respectively. The results demonstrated that MMA-based resin cements exhibited stronger bonding to PEEK than composite-based resin cements.
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Wang, Guoling, Xiaofei Huang, Yufeng Wu, Qian Zhang, Suhua Ma, and Weifeng Li. "Hydration and Properties of Cement in the Belite-Ye′elimite-Ternesite System." Materials 15, no. 8 (April 11, 2022): 2792. http://dx.doi.org/10.3390/ma15082792.
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Energy consumption and carbon emissions are lower in the production of belite-ye′elimite-ternesite (C2S-C4A3$-C5S2$, BYT) clinker than Portland cement (PC) clinker. BYT cement can combine the early strength of CSA cements and the durability of belite cements. X-ray diffraction, mercury intrusion porosimetry, isothermal conduction calorimetry and scanning electron microscope were conducted to investigate the hydration process of BYT cement. The hydration products of BYT cement include mainly ettringite, strätlingite and some amorphous AH3 (aluminum hydroxide). Ternesite did prove an early reactivity in BYT cement. The reaction of ternesite with AH3 occurs on the surface of ternesite. Ternesite delays the second heat flow peak of ye′elimite. The strength of BYT cement containing 10% ternesite in the prepared clinker exceeds that of other cement at all ages.
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Tumidajski, P. J., L. Fiore, T. Khodabocus, M. Lachemi, and R. Pari. "Comparison of the cement efficiency of two type GU cements." Canadian Journal of Civil Engineering 33, no. 3 (March 1, 2006): 343–46. http://dx.doi.org/10.1139/l05-127.
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The cement efficiency or reactivity of two type GU cements sold in the southern Ontario market was studied using compressive strength measurements of concrete coupled with Abram's Law. At 28 days, it was found that there was a marked performance difference between the two cements. For example, at 28 days, the cement efficiencies were 0.0889 and 0.0953 MPa·kg 1. The difference in cement efficiency was related somewhat to cement fineness. It was observed that the 28 day mortar strengths represented a good predictor of the relative efficiencies of the cement.Key words: cement, concrete, compressive strength, reactivity, efficiency.
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Mazmanyan, Smbat V., Gayane Papyan, Tamara Sargsyan, Armine Baghdagyulyan, Tatevik Paytyan, and Hovsep Hoveyan. "The Influence of Cement Grain Structure on Physical and Mechanical Properties of Cement." Key Engineering Materials 906 (January 11, 2022): 31–37. http://dx.doi.org/10.4028/www.scientific.net/kem.906.31.
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The paper presents the study of morphological characteristics of cement particles and reveals the influence of the structure of the cement grain composition on the physical and mechanical properties of cement. The following portland cements produced by “Hrazdan Cement Corporation” LLC, which have 52,5 MPa and 42,5 MPa compressive strength limit and hydraulic additives up to 20% and over 20% have been used for the experiment: CEM II/ A-P 42,5N, CEM II/ B-P 42,5N, CEM II/A-Q 42,5N, CEM II/B-Q, CEM II/A-L 42,5N, CEM II/B-L 42,5N, CEM II/A-M 42,5N, CEM II/B-M, CEM III/A-S 42,5N and CEM III/B-S 42,5N. Grain distribution in all the samples has been studied using a CILAS laser analyzer. Microscopic analysis of all the fractions has been carried out with the help of James Swift optical microscope. The given grain compositions have undergone chemical analysis in compliance with the requirements of interstate ISO 5382-2019 and ASTM C114-18 standards. Experimental studies and analyses show that the cements with microsilica have the highest value of water-cement ratio-W/C = 0.7, the highest by volume compression are the cements with volcanic slag-4 mm, the beginning of the bonding period is the longest in case of limestone cements - t = 140 minutes, followed by microsilica cements, and in third place there are artificial slag cements, the results of which are as follows: 130; 124 minutes. The summarized data show that microsilica cements have the highest compressive strength limit among the cements having the same percentage of additives-48.87 MPa.
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Bernard, Ellina, Hoang Nguyen, Shiho Kawashima, Barbara Lothenbach, Hegoi Manzano, John Provis, Allan Scott, Cise Unluer, Frank Winnefeld, and Paivo Kinnunen. "MgO-based cements – Current status and opportunities." RILEM Technical Letters 8 (November 16, 2023): 65–78. http://dx.doi.org/10.21809/rilemtechlett.2023.177.
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The cement industry is a major contributor to the anthropogenic CO2 emissions, with about 8% of all emissions coming from this sector. The global cement and concrete association has set a goal to achieve net-zero CO2 concrete by 2050, with 45% of the reduction coming from alternatives to Portland cement, substitution, and carbon capture and utilization/storage (CCU/S) approaches. Magnesia-based cements offer a conceivable solution to this problem due to their potential for low-to-negative CO2 emissions (CCU/S) but also being alternatives to Portland cement. The sources of magnesia can come from magnesium silicates or desalination brines which are carbon free for raw-material-related emissions (cf. carbonated rocks). This opens up possibilities for low or even net-negative carbon emissions. However, research on magnesia-based cements is still in its early stages.
In this paper, we summarize the current understanding of different MgO-based cements and their chemistries: magnesia oxysulfate cement, magnesia oxychloride cement, magnesia carbonate cement, and magnesia silicate cement. We also discuss relevant research needed for MgO-based cements and concretes including the issues relating to the low pH of these cements and suitability of steel reinforcement. Alternatives reinforcements, suitable admixtures, and durability studies are the most needed for the further development of MgO-based concretes to achieve a radical CO2 reduction in this industry. Additionally, techno-economic and life cycle assessments are also needed to assess the competition of raw materials and the produced binder or concrete with other solutions. Overall, magnesia-based cements are a promising emerging technology that requires further research and development to realize their potential in reducing CO2 emissions in the construction industry.
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Askar Zhambulovich, Aimenov, Khudyakova Tatyana Mikhailovna, Sarsenbayev Bakytzhan Kudaibergenovich, Dzhakipbekova Nagima Ormanovna, Ali Khalid Abdul Khalim Kheidar, and Alvein Yaser Mukhamed Ali. "Studying the Mineral Additives Effect on a Composition and Properties of a Composite Binding Agent." Oriental Journal of Chemistry 34, no. 4 (August 20, 2018): 1945–55. http://dx.doi.org/10.13005/ojc/3404031.
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A Portland cement is a basic initial component for concrete and reinforced concrete manufacture, which defines their technical-economic and operational properties. One of a perspective ways of increase in the efficiency of cement production without essential change of its technology is inclusion of various mineral additives influencing on a structure and properties of a cement stone. As power inputs make the most part of the costs necessary for cement manufacture, the cement industry is interested in decrease in fuel and electric power expenditures per 1 tonne of cement. To reach the decrease in power inputs and at the same time to raise the environmental safety of cement production the cement industry is recently focused on increase in output of composite cements. Composite cements not only promote optimization of the production in terms of ecology, but also can provide such technical advantages as lower hydration heat, higher chemical resistance and placeability.
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Mrema, Alex Lyatonga. "Comparison of the Properties of Portland Cement and Portland-Limestone Cement." Tanzania Journal of Engineering and Technology 33, no. 1 (June 30, 2010): 1–8. http://dx.doi.org/10.52339/tjet.v33i1.448.
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A study was made in a cement factory in Dar es Salaam, Tanzania, where OrdinaryPortland Cement (CEM I 42.5N) and Portland-limestone cement (PLC) which has thebrand name Twiga Cement Extra (CEM II/A-L/32.5R) are produced and conforming to theTanzania Standard TZS 727 (Part1): 2002, which is equivalent to EN 197 published by thecommittee for European normalization (CEN). A comparison was made between the twotypes of cements in terms of physical, chemical and mechanical properties. It was foundout that they all complied with the standards, that there was no significant difference intheir setting times and that the Portland cement had higher strengths than the PLC. It was also observed that there was a slightly lower water demand for the same consistency when compared to OPC and hence there is an improvement of the cohesiveness of a concrete mix when PLC is used. It was concluded, however, that the two cements are different and that using the two cements interchangeably as is done in Tanzania is wrong because they donot have equivalent strengths and therefore equivalent performance since the PLC is not ptimized. Portland-limestone cement (PLC) is known to offer significant energy savings and green house gas (GHG) reduction (up to 10% GHG savings) over conventional Portland cement while at the same time providing comparable performance if optimized.
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Fonseca, Renata Garcia, Juliana Gomes dos Santos, and Gelson Luis Adabo. "Influence of activation modes on diametral tensile strength of dual-curing resin cements." Brazilian Oral Research 19, no. 4 (December 2005): 267–71. http://dx.doi.org/10.1590/s1806-83242005000400006.
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In metallic restorations, the polymerization of dual-curing resin cements depends exclusively on chemical activation. The effect of the lack of photoactivation on the strength of these cements has been rarely studied. This study evaluated the influence of activation modes on the diametral tensile strength (DTS) of dual-curing resin cements. Base and catalyst pastes of Panavia F, Variolink II, Scotchbond Resin Cement, Rely X and Enforce were mixed and inserted into cylindrical metal moulds (4 x 2 mm). Cements were either: 1) not exposed to light (chemical activation = self-cured groups) or 2) photoactivated through mylar strips (chemical and photo-activation = dual-cured groups) (n = 10). After a 24 h storage in 37ºC distilled water, specimens were subjected to compressive load in a testing machine. A self-curing resin cement (Cement-It) and a zinc phosphate cement served as controls. Comparative analyses were performed: 1) between the activation modes for each dual-curing resin cement, using Student’s t test; 2) among the self-cured groups of the dual-curing resin cements and the control groups, using one-way ANOVA and Tukey’s test (alpha = 0.05). The dual-cured groups of Scotchbond Resin Cement (53.3 MPa), Variolink II (48.4 MPa) and Rely X (51.6 MPa) showed higher DTS than that of self-cured groups (44.6, 40.4 and 44.5 MPa respectively) (p < 0.05). For Enforce (48.5 and 47.8 MPa) and Panavia F (44.0 and 43.3 MPa), no significant difference was found between the activation modes (p > 0.05). The self-cured groups of all the dual-curing resin cements presented statistically the same DTS as that of Cement-It (44.1 MPa) (p > 0.05), and higher DTS than that of zinc phosphate (4.2 MPa). Scotchbond Resin Cement, Variolink II and Rely X depended on photoactivation to achieve maximum DTS. In the absence of light, all the dual-curing resin cements presented higher DTS than that of zinc phosphate and statistically the same as that of Cement-It (p > 0.05).
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Schulze, Simone Elisabeth, and Joerg Rickert. "Durability of concretes with ternary cements." ce/papers 6, no. 6 (December 2023): 140–45. http://dx.doi.org/10.1002/cepa.2912.
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AbstractThe production of cements with calcined clay is becoming increasingly important for the cement industry for ecological and economic reasons. Especially the combination of the cement constituents granulated blast furnace slag (S) and calcined clay (Q) next to Portland cement clinker (K) is very promising in terms of cement properties, durability and CO2 saving potential. Due to a lack of knowledge and experience, such KSQ cements have not yet been produced in Europe.With the help of design of experiments and statistical evaluation, both the influence of the cement composition and the reactivity of the clinker and calcined clays used on the cement and concrete properties were determined. For this purpose, a total of 64 different cement compositions consisting of at least 20 wt.% clinker (two different qualities), a maximum of 59 wt.% granulated blast furnace slag and a maximum of 49 wt.% calcined clay (two different qualities) were investigated.It could be shown that in a wide range of compositions, the production of KSQ cements of strength class 42,5 acc. EN 197‐1 is possible, whereby the water demand of the cements was mainly determined by the amount of calcined clay. Most of the corresponding concretes exhibited a high resistance to carbonation, chloride and freeze thaw attack.
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Huang, Zi, Jiaoyue Wang, Longfei Bing, Yijiao Qiu, Rui Guo, Ying Yu, Mingjing Ma, et al. "Global carbon uptake of cement carbonation accounts 1930–2021." Earth System Science Data 15, no. 11 (November 7, 2023): 4947–58. http://dx.doi.org/10.5194/essd-15-4947-2023.
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Abstract. The main contributor to the greenhouse gas (GHG) footprint of the cement industry is the decomposition of alkaline carbonates during clinker production. However, systematic accounts for the reverse of this process – namely carbonation of calcium oxide and other alkaline oxides and/or hydroxides within cement materials during cements' life cycles – have only recently been undertaken. Here, adopting a comprehensive analytical model, we provide the most updated estimates of CO2 uptake by cement carbonation. The accumulated amount of global CO2 uptake by cements produced from 1930 to 2021 is estimated to be 22.9 Gt CO2 (95 % confidence interval, CI: 19.6–26.6 Gt CO2). This amount includes the CO2 uptake by concrete, mortar, construction waste and kiln dust, accounting for 30.1 %, 58.5 %, 4.0 % and 7.1 % respectively. The cumulative carbon uptake by cement materials from 1930 to 2021 offsets 55.1 % of the emissions from cement production (41.6 Gt CO2, 95 % CI: 38.7–47.2 Gt CO2) over the same period, with the greater part coming from mortar (58.5 % of the total uptake). China has the highest cement carbon uptake, with cumulative carbonation of 7.06 Gt CO2 (95 % CI: 5.22–9.44 Gt CO2) since 1930. In addition, the carbon uptake amounts of the USA, EU, India and the rest of the world took 5.0 %, 23.2 %, 5.6 % and 34.8 % separately. As a result of rapidly increased production in recent years, over three-quarters of the cement carbon uptake has occurred since 1990. Additionally, our results show little impact by the COVID-19 pandemic on cement production and use, with carbon uptake reaching about 0.92 Gt CO2 (95 % CI: 0.78–1.10 Gt CO2) in 2020 and 0.96 Gt CO2 (95 % CI: 0.81–1.15 Gt CO2) in 2021. Our uniformly formatted and most updated cement uptake inventories provide coherent data-based support for including cement carbon uptake into future carbon budgets from the local to global scale. The latest version contains the uptake data till 2021, showing the global uptake's increasing pattern and offering more usable and relevant data for evaluating cement's carbon uptake capacity. All the data described in this study are accessible at https://doi.org/10.5281/zenodo.7516373 (Bing et al., 2023).
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Grilo, Maria J., João Pereira, and Carla Costa. "Waste Marble Dust Blended Cement." Materials Science Forum 730-732 (November 2012): 671–76. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.671.
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Marble processing activities generates a significant amount of waste in dust form. This waste, which is nowadays one of the environmental problems worldwide, presents great potential of being used as mineral addition in blended cements production. This paper shows preliminary results of an ongoing project which ultimate goal is to investigate the viability of using waste marble dust (WMD), produced by marble Portuguese industry, as cement replacement material. In order to evaluate the effects of the WMD on mechanical behaviour, different mortar blended cement mixtures were tested. These mixtures were prepared with different partial substitution level of cement with WMD. Strength results of WMD blended cements were compared to control cements with same level of incorporation of natural limestone used to produce commercial Portland-limestone cements. The results obtained show that WMD blended cements perform better than limestone blended cements for same replacement level up to 20% w/w. Therefore, WMD reveals promising attributes for blended cements production.
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KALANTARI, MARYAM, and ATA HASHEMI. "EFFECT OF ANTIBIOTICS AUGMENTATION AND STORAGE CONDITION ON IMPACT RESISTANCE OF ORTHOPEDIC BONE CEMENT." Journal of Mechanics in Medicine and Biology 17, no. 01 (February 2017): 1750019. http://dx.doi.org/10.1142/s0219519417500191.
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Antibiotic-impregnated poly(methyl methacrylate) (PMMA) bone cement has been successfully used to treat infected joint arthroplasties and surgeons have advocated the use of antibiotic-treated bone cement to prevent possible infections in joint replacement surgeries. However, there is a concern that this addition may adversely affect the mechanical properties of the bone cement. In most cases, the addition of antibiotics to bone cement has been reported to lower its mechanical strength. The uniaxial, biaxial and three/four point bending tests of antibiotic-impregnated bone cement have been extensively performed and well documented. However, only a few documents have focused on the impact strength of bone cement. The present study reports the impact tests of control and antibiotic loaded bone cements at different temperatures and aging conditions. According to the results, the addition of gentamicin or vancomycin significantly reduced the samples' impact strength. Moreover, the samples aged in saline at 23[Formula: see text]C were more resistant than the samples aged in air at 23[Formula: see text]C. Furthermore, raising the storage temperature from 23[Formula: see text]C to 37[Formula: see text]C significantly lowered the bone cement's impact strength in both control and antibiotic loaded samples.
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Fordán, Tamás. "Production of chromate reduced cement at Danube-Drava Cement, Plant Vác." Epitoanyag - Journal of Silicate Based and Composite Materials 57, no. 4 (2005): 116–21. http://dx.doi.org/10.14382/epitoanyag-jsbcm.2005.17.
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Levashov, Gleb, Muhammad Hasibul Hasan, Arion Frakulli, Janneza Macaalay, and Kian Nahad. "An Overview of Bone Cement Compositions used in Vertebroplasty and Their Viability in Clinical Settings." International Journal of Engineering Materials and Manufacture 9, no. 1 (January 26, 2024): 1–14. http://dx.doi.org/10.26776/ijemm.09.01.2024.01.
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Vertebroplasty is a minimally invasive surgical procedure wherein a particular composition of bone cement is injected into a fractured vertebra in an attempt to restore joint mobility and reduce perceived pain. It is especially common in the treatment of osteoporotic vertebral compression fractures, most typically experienced by older women. The formulation of this bone cement takes on many forms, the most common being the group of cements known as polymethyl methacrylate acrylic bone cements. The different varieties of acrylic bone cements are investigated and compared, in addition to new potential rival materials being developed to rival the dominance of acrylic bone cements in the vertebroplasty bone cement industry. Factors such as biomechanical strength, handling, osteoconductivity/inductivity, biodegradability, additive delivery, and porosity are considered. While the main drawbacks of acrylic bone cements (significant biomechanical mismatch with vertebrae and lack of biodegradability and osteoconductivity) present opportunities for new solutions to enter the market to compete, the industry standard in vertebroplasty remains the most widely applicable, and thus wisest, cement choice for the procedure. Keywords: Vertebroplasty, Minimally Invasive Surgery, Biodegradability, Bone Cement
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Dziuk, Damian, Zbigniew Giergiczny, and Albin Garbacik. "Calcareous fly ash as a main constituent of common cements." Roads and Bridges - Drogi i Mosty 12, no. 1 (February 1, 2014): 57–69. http://dx.doi.org/10.7409/rabdim.013.005.
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The results of tests concerning properties of cements containing calcareous fly ash obtained by a process of lignite combustion are presented in the paper. The scope of the study includes: Portland fly-ash cements CEM II/A,B-W; Portland composite cements CEM II/B-M containing a mixture of calcareous fly ash (W) and granulated blast furnace slag (S), siliceous fly ash (V) or limestone (LL), as well as pozzolanic cements CEM IV/B-W and CEM IV/A,B (V-W). Standard properties of cements, including cement water demand, mortars consistency and mechanical properties, are described in the paper. The obtained results have proven that use of calcareous fly ash in the production of common cements, especially Portland composite cement CEM II/B-M, is possible. Cements containing calcareous fly ash, regarding setting time, soundness and compressive strength, exhibit similar properties to the ones of cements with additives (CEM II – CEM V), available on the market for a long time. The use of calcareous fly ash in greater amount in cement composition (above 20%) results in the increased water demand and deterioration of mortars rheological properties. The process of intergrinding of fly ash with clinker in cement production results in decreased negative impact on cement water demand.
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Fontaine, Marie-Laure, Christèle Combes, Thierry Sillam, Gérard Dechambre, and Cristian Rey. "New Calcium Carbonate-Based Cements for Bone Reconstruction." Key Engineering Materials 284-286 (April 2005): 105–8. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.105.
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The feasibility of calcium carbonate-based cements involving the re-crystallization of metastable calcium carbonate varieties has been demonstrated. Two cement compositions were obtained by mixing either calcium carbonate phases (cement A) or a calcium carbonate and a calcium phosphate phase (cement B) with an aqueous media. These cements set and hardened after 30 minutes and 90 minutes respectively. The final composition of cement A was calcite and aragonite whereas cement B lead to a carbonated apatite analogous to bone mineral. Despite poor mechanical properties the presence of a high carbonate content in the final phase might be of interest to increase the cement resorption rate and to favour its replacement by bone tissue. First assays of implantation performed on fresh anatomical pieces (fresh cadavers) at 37°C revealed important advantages of such cement compositions: easiness of use, rapid setting, good adhesion to bone, very good homogeneity and stability of the cement.
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Marangu, Joseph Mwiti, Joseph Karanja Thiong’o, and Jackson Muthengia Wachira. "Review of Carbonation Resistance in Hydrated Cement Based Materials." Journal of Chemistry 2019 (January 1, 2019): 1–6. http://dx.doi.org/10.1155/2019/8489671.
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Blended cements are preferred to Ordinary Portland Cement (OPC) in construction industry due to costs and technological and environmental benefits associated with them. Prevalence of significant quantities of carbon dioxide (CO2) in the atmosphere due to increased industrial emission is deleterious to hydrated cement materials due to carbonation. Recent research has shown that blended cements are more susceptible to degradation due to carbonation than OPC. The ingress of CO2 within the porous mortar matrix is a diffusion controlled process. Subsequent chemical reaction between CO2 and cement hydration products (mostly calcium hydroxide [CH] and calcium silicate hydrate [CSH]) results in degradation of cement based materials. CH offers the buffering capacity against carbonation in hydrated cements. Partial substitution of OPC with pozzolanic materials however decreases the amount of CH in hydrated blended cements. Therefore, low amounts of CH in hydrated blended cements make them more susceptible to degradation as a result of carbonation compared to OPC. The magnitude of carbonation affects the service life of cement based structures significantly. It is therefore apparent that sufficient attention is given to carbonation process in order to ensure resilient cementitious structures. In this paper, an indepth review of the recent advances on carbonation process, factors affecting carbonation resistance, and the effects of carbonation on hardened cement materials have been discussed. In conclusion, carbonation process is influenced by internal and external factors, and it has also been found to have both beneficial and deleterious effects on hardened cement matrix.
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Mehta, Shak, Tarun Kalra, Manjit Kumar, Ajay Bansal, Abhiskek Avasthi, and Shefali Singh Malik. "To Evaluate the Solubility of Different Permanent and Temporary Dental Luting Cements in Artificial Saliva of Different pH Values at Different Time Intervals—An In Vitro Study." Dental Journal of Advance Studies 8, no. 03 (August 5, 2020): 092–101. http://dx.doi.org/10.1055/s-0040-1714321.
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Abstract Introduction Luting cements are susceptible to attack by moisture during the initial setting period that can result in an increased solubility. The aim of this in vitro study was to evaluate the solubility of different permanent and temporary dental luting cements in artificial saliva of different pH values at different time intervals. Materials and Methods Eight commercial luting cements were used. Out of which five were permanent cements (Rely X lute2, zinc phosphate cement, zinc polycarboxylate cement, Rely X U-200, GC GIC) and three temporary cements (ZOE, Oratemp NE, Temposil). A total of 200 samples were made into 25 specimens of each cement (five samples for each study solution group). The samples were made of dimension 20 mm × 1.5 mm in the metal mold. Once the cements were set, they were removed and after 3 minutes of removal they were placed in the incubator at 37°C ± 1 for 1 hour. Specimens of each cement type were separated into five groups for evaluation and comparison in distilled water and artificial saliva with four different pH values (pH 3, pH 5, pH 7, and pH 9). Percentage of solubility was calculated as 100% times weight loss divided by initial weight of the specimen. Results When all permanent cements were tested the result showed that Rely X U-200 showed least dissolution even after 28 days, followed by Rely X lute-2, then Glass ionomer cement then zinc polycarboxylate cement and then zinc phosphate cement which gave maximum dissolution. Conclusion When all temporary cements were tested the result showed that Temposil showed least dissolution even after 28 days, followed by OraTemp NE, compared with zinc oxide eugenol which gave maximum dissolution.
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Kumar, A. Srujan, K. Naga Meenakshi, G. Venkata Narayana reddy, G. Raju, Ch Honey, and P. Anil Kumar reddy. "Development of New Composites Using Industrial by Products." International Journal of Innovative Research in Engineering and Management 10, no. 6 (December 30, 2022): 126–29. http://dx.doi.org/10.55524/ijirem.2022.9.6.22.
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In this paper thesis describes an experimental investigation of magnesium based cement mortar which consists of fly ash, magnesium oxide (MgO), magnesium Phosphate (MgPO4) and Phosphate tailings. This magnesia based cements are emerged as a viable alternative to Portland cement, with both technical and sustainability advantages. This study aims to use the mixture of cement, fly ash and magnesia. The major drawback of delayed setting time can be eliminated with the use of magnesia based cement. Hence, in this study different admixtures such as magnesium oxide, magnesium phosphate, phosphate tailings are attempted. Initial and final setting time of plain cement, fly ash cement and magnesia based cement are determined and found that the small dosage of magnesium compound reduced the setting time. Further, magnesia based cements are reported to be used along with sea water without much negative effect. In view of all these, this study proposed a magnesia based cement as an alternative for conventional Portland cement. Industrial wastes such as fly ash, and phosphate tailings are used in this study.
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Naqi, Ali, and Jeong Jang. "Recent Progress in Green Cement Technology Utilizing Low-Carbon Emission Fuels and Raw Materials: A Review." Sustainability 11, no. 2 (January 21, 2019): 537. http://dx.doi.org/10.3390/su11020537.
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The cement industry is facing numerous challenges in the 21st century due to depleting natural fuel resources, shortage of raw materials, exponentially increasing cement demand and climate linked environmental concerns. Every tonne of ordinary Portland cement (OPC) produced releases an equivalent amount of carbon dioxide to the atmosphere. In this regard, cement manufactured from locally available minerals and industrial wastes that can be blended with OPC as substitute, or full replacement with novel clinkers to reduce the energy requirements is strongly desirable. Reduction in energy consumption and carbon emissions during cement manufacturing can be achieved by introducing alternative cements. The potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies. Seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed. The study provides a comprehensive analysis of options for future cements, and an up-to-date summary of the different alternative fuels and binders that can be used in cement production to mitigate carbon dioxide emissions. In addition, the practicalities and benefits of producing the low-cost materials to meet the increasing cement demand are discussed.
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Al-Saleh, Samer, Turki W. Aboghosh, Mousa S. Hazazi, Khalid A. Binsaeed, Abdulaziz M. Almuhaisen, Huda I. Tulbah, Amal S. Al-Qahtani, et al. "Polymer-Based Bioactive Luting Agents for Cementation of All-Ceramic Crowns: An SEM, EDX, Microleakage, Fracture Strength, and Color Stability Study." Polymers 13, no. 23 (December 2, 2021): 4227. http://dx.doi.org/10.3390/polym13234227.
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The aim of the study was to compare microleakage and fracture loads of all ceramic crowns luted with conventional polymer resins and polymeric bioactive cements and to assess the color stability of polymeric bioactive cements. Seventy-five extracted premolar teeth were tested for fracture loads and microleakage in all-ceramic crowns cemented with two types of polymeric bioactive cements and resin cements. In addition, the degree of color change for each cement with coffee was assessed. Thirty maxillary premolar teeth for fracture loads and thirty mandibular premolar teeth for microleakage were prepared; standardized teeth preparations were performed by a single experienced operator. All prepared specimens were randomly distributed to three groups (n = 20) based on the type of cement, Group 1: resin cement (Multilink N); Group 2: polymeric bioactive cement (ACTIVA); Group 3: polymeric bioactive cement (Ceramir). The cementation procedures for all cements (Multilink, ACTIVA, and Ceramir) were performed according to the manufacturers’ instructions. All specimens were aged using thermocycling for 30,000 cycles (5–55 °C, dwell time 30 s). These specimens were tested using the universal testing machine for fracture strength and with a micro-CT for microleakage. For the color stability evaluation, the cement specimens were immersed in coffee and evaluated with a spectrometer. Results: The highest and lowest means for fracture loads were observed in resin cements (49.5 ± 8.85) and Ceramir (39.8 ± 9.16), respectively. Ceramir (2.563 ± 0.71) showed the highest microleakage compared to resin (0.70 ± 0.75) and ACTIVA (0.61 ± 0.56). ACTIVA cements showed comparable fracture loads, microleakage, and stain resistance compared to resin cements.
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Hloch, Sergej, Peter Monka, Pavol Hvizdos, Dagmar Jakubeczyová, Drazan Kozak, Katarina Colic, Ján Kľoc, and Dagmar Magurová. "Thermal manifestations and nanoindentation of bone cements for orthopaedic surgery." Thermal Science 18, suppl.1 (2014): 251–58. http://dx.doi.org/10.2298/tsci130901186h.
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Improving of bone cements properties is possible by research of variables influencing exothermal behaviour and mechanical properties. Paper deals with exothermal behaviour experimental evaluation of bone cements used for medical purposes. Specimens were prepared by a conventional manual mixing technique. The work addresses primary risk factor associated with application of bone cement to femoral canal. Different size samples of bone cement has been created with diameter d = 2; 5;12,5 mm fixed in dentacryl. As an experimental material, Palacos R+G high viscosity, radiopaque bone cement containing Gentamicin and Radiopaque bone cement Antibiotic Simplex with Tobramycin, was used. Thermal effect during exothermic polymerisation was measured with period 1 minute. Evaluated factors were mass and thickness of bone cement. Significant influence of bone cement mass on temperature has been found.
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Pytiak, Andrew V., Nathaniel Jove, Shulin He, Laryssa A. Korduba-Rodriguez, Marc Esformes, and David C. Markel. "The Effect of Ambient Temperature and Implantation Time on the Material Properties of Two Viscosity-Differing Cements Using American Society of Testing and Materials Methodology." Journal of Knee Surgery 33, no. 06 (May 2, 2019): 560–64. http://dx.doi.org/10.1055/s-0039-1681090.
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AbstractAmbient temperature and time to implantation can affect the material properties of polymethylmethacrylate bone cement, and cement intrusion depth has been shown to affect implant fixation. The purpose of this study was to examine the effects of ambient temperature and time to implantation on depth of intrusion, and the effect of ambient temperature on setting time. Two types of cements were evaluated: cement A (Simplex P,medium Q7 viscosity) and cement B (Palacos R, high viscosity). Dough, working and setting times were determined, as well as intrusion depth, at different temperatures per American Society of Testing and Materials (ASTM) protocol F451. A vacuum mixer was used in a temperature- and humidity-controlled environment at 60, 65, and 70°F. At each temperature, the cement was placed into an intrusion mold at 0, 50, and 100% of working time. Increasing ambient temperature resulted in a significant decrease in dough and working and setting times for both cements (p = 0.038 − < 0.001). At each working time point and temperature, cement A showed significantly more intrusion than cement B (p = 0.044 − < 0.001). There was no effect of temperature on intrusion depth regardless of working time to implantation for either cement with the exception of cement B when comparing 60 versus 70°F at 0% working time (p = 0.004). Both cements showed a significant decrease in intrusion as time to implantation increased (p < 0.001). In conclusion, there are large inherent differences in properties of commercially available cements, and these properties are affected by such variables as time to implantation and ambient temperatures. An understanding of these properties may aid the surgeon in optimizing surgical outcomes.
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Baylavlı, Hasan, and Eren Gödek. "Use of Ceramic Tile Wastes as Raw Substitution Material in the Production of Blended Cement." Buildings 14, no. 9 (September 18, 2024): 2942. http://dx.doi.org/10.3390/buildings14092942.
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In this study, the feasibility of using ceramic wastes in the production of blended cement was evaluated by substituting limestone with ceramic waste at the percentages of 5, 10, 15, 20, and 28% before the milling stage. The chemical, physical, and mechanical properties of the cements were determined according to relevant standards, and the results were compared. The chemical analysis showed that the SiO2 content of the cements increased with higher ceramic waste substitution percentages, while the CaCO3 content decreased. The grindability of cements decreased with increased ceramic waste ratios, slightly reducing the Blaine specific surface area values. The water consistency for the cements was set at 28%, and all the cements met the standard limitations. The spread diameters for all types of cements were similar and practically usable in terms of workability. The cements containing ceramic waste either maintained or extended the setting time. All cements with ceramic waste exhibited higher flexural and compressive strength compared to the reference cement. The highest flexural strengths were achieved with a 28% ceramic waste substitution ratio across all curing ages. Regarding compressive strengths, all cements exhibited higher compressive strength than 10 MPa at 2 days and 32.5 MPa at 28 days, classifying them as 32.5 R-type blended cements. When the medium- (56–90 days) and long-term (365 days) compressive strengths were compared, the highest strength values were obtained from the cement with a 28% ceramic waste substitution. Although limestone-blended cement is emerging as a promising alternative to traditional Portland cement, these types of cement still contribute to environmental degradation due to the extraction of natural limestone resources through quarrying. This study showed that blended cements can be produced using ceramic waste, providing a more sustainable and environmentally friendly solution for the construction industry.
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Ling, Long, Yulin Chen, and Raj Malyala. "Assessment of Degree of Conversion and Volumetric Shrinkage of Novel Self-Adhesive Cement." Polymers 16, no. 5 (February 21, 2024): 581. http://dx.doi.org/10.3390/polym16050581.
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The degree of monomer conversion and polymerization shrinkage are two of the main reasons for potential adhesion failure between the tooth structure and the restoration substrate. To evaluate the degree of conversion and polymerization shrinkage of a newly developed self-adhesive resin cement, the degree of conversion (DC) was measured using FTIR under different activation modes, temperatures, and times. Volumetric shrinkage was tested using the AcuVol video imaging method. The experimental cement showed a higher DC than other cements under self-curing. The DC of the experimental cement was higher than that of other cements, except SpeedCem Plus under light curing. The experimental cement had a higher DC than other cements, except SpeedCem Plus in some conditions under dual curing. All self-adhesive cements had a higher DC at 37 °C than at 23 °C under self-curing, and there was no statistical difference between 23 °C and 37 °C under light curing. All self-adhesive cements showed a significantly higher DC at 10 min than at 5 min under self-curing. There was no statistical difference between 5 min and 10 min for most cements under dual curing. All self-adhesive cements statistically had the same volumetric shrinkage under light curing and self-curing. The newly developed self-adhesive resin cement exhibited a higher degree of conversion and similar volumetric shrinkage compared to these commercial self-adhesive resin cements.
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Honda, Michiyo, Toshiisa Konishi, Minori Mizumoto, and Mamoru Aizawa. "In Vitro Biological Evaluation of Anti-Tumor Effect of the Chelate-Setting Hydroxyapatite Cement." Key Engineering Materials 529-530 (November 2012): 173–77. http://dx.doi.org/10.4028/www.scientific.net/kem.529-530.173.
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Cancers frequently metastasize to bone, where it leads to secondary tumor growth, and osteolytic bone degradation. Bone metastases are often associated with fractures and severe pain resulting in decreased quality of life. Accordingly, effective therapies to inhibit the development or progression of bone metastases will have important clinical benefits. Bone cement, one of the powerful tools as bone substitutes, is used to fill the resection voids. The aim of this study was to develop a local drug delivery system using HAp cement as a carrier of chemotherapeutic agents. In the present study, we have fabricated chelate-setting apatite cements (IP6-HAp cements) using HAp particles surface-modified with inositol hexaphosphate (IP6) and evaluated their anti-tumor effect. Human osteosarcoma (HOS) cultured on IP6-HAp cements (over 3000 ppm IP6) resulted in inhibition of cell growth. DNA microarray analysis indicated changes in the expression of apoptosis-related genes on IP6-HAp cement surface-modified with 5000 ppm IP6 compared with HAp cement, suggesting activation of apoptosis machinery by IP6-HAp cement. To clarify the mechanism of anti-tumor effect of IP6-HAp cement, the properties of cement were investigated. The release kinetics of IP6 from IP6-HAp cement showed that the level of released IP6 was insufficient to induce anti-tumor activity. These results led us to consider that locally high concentration of IP6 which was released from cement acts on the cells directly as anti-tumor agent and induces the apoptosis. Consequently, IP6-HAp cement might gain the anti-tumor effect and act as a carrier for local drug delivery system.