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Journal articles on the topic 'Blended cements'

Author: Grafiati
Published: 4 April 2023

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1

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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2

Staněk, Theodor. "Potential Application of Belite Clinker." Advanced Materials Research 1000 (August 2014): 7–11. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.7.

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Blended cements were prepared from belite clinker burned in a model kiln and ordinary industrial alite clinker. The mechanical and physical properties of these blended cements were determined. The difference in the development of hydration heat of belite and alite cements by using calorimetric method was determined also. The results show that strengths of prepared belite cement after 28 days of hydration are equal to those of industrial alite cement. Short time strengths are suitable for blended cements up to 30 % content of belite clinker. These results demonstrate the possibility of separate industrial belite clinker production next to common alite clinker manufactory and production of economically and ecologically advantageous blended Portland cements with suitable technological properties.
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3

Ustabas, Ilker, Sakir Erdogdu, Ihsan Omur, and Erol Yilmaz. "Pozzolanic Effect on the Hydration Heat of Cements Incorporating Fly Ash, Obsidian, and Slag Additives." Advances in Civil Engineering 2021 (October 8, 2021): 1–12. http://dx.doi.org/10.1155/2021/2342896.

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Made up of an engineered mix of ordinary Portland cement (OPC) with artificial pozzolans such as trass, fly ash, and slag, the blended cements have been intensely employed within cementitious materials. The main reasons behind this intensive use can be clarified by enhanced workability/strength, the high resistance to chloride/sulfate, reduced permeability/alkali-silica reaction, and a drop in the heat generated by cement’s hydration. The use of cementitious blends within concrete not only offers durable products but also cuts climate impact by energy saving and falling CO2 emissions. This study presents pozzolanic effect on the hydration heat of cements incorporating fly ash, obsidian, and slag additives. The blended cements were manufactured by three different replacement ratios of 20%, 30%, and 50%. The change in the hydration heat of obsidian-, fly ash-, and slag-based cements was observed by several Turkish standards (TS EN 196-8 and TS EN 196-9). Mortars were used for determining the uniaxial strengths of obsidian-, fly ash-, and slag-based cements. The results show that cement’s hydration heat decreases as the rate of additives (e.g., obsidian) increases from 20% to 50%. The cement’s fineness greatly affects its hydration heat. Increasing the refinement of pozzolanic material to a certain level (30%) leads to an increase in the hydration temperature. After reaching this level, there is no clear relation between the fineness and the replacement rate of pozzolans. As a result, the findings of this work will provide a good understanding of artificial pozzolans on performance and quality of obsidian-, fly ash-, and slag-based cements.
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4

Hájková, Iveta, Karel Dvořák, Dominik Gazdič, and Marcela Fridrichová. "Technological Properties Testing of Blended Portland Cements with Fluidized Filter Ash." Materials Science Forum 865 (August 2016): 27–31. http://dx.doi.org/10.4028/www.scientific.net/msf.865.27.

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The work aims to study the behaviour of blended cement with fluidized filter ash (FFA) considering to formation of the increased proportion of ettringite and its eventual transformation into thaumasite. In part of an experiment there were prepared three cements, two of them served as a reference one-component and the reference blended cement with limestone, a third one was tested blended cement with a FFA. All three cements were put to determination of basic technological properties and next they were observed during hydration process.
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5

Sicakova, A., E. Kardosova, and M. Spak. "Perlite Application and Performance Comparison to Conventional Additives in Blended Cement." Engineering, Technology & Applied Science Research 10, no. 3 (June 7, 2020): 5613–18. http://dx.doi.org/10.48084/etasr.3487.

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This study compares the performance of perlite with that of conventional additives in blended cements. The results of the application of Perlite Powder (PP) as a component of blended cements in two different proportions (30% and 50%) are presented and compared with standard additives of fly ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS). Moreover, perlite is tested as a component of ternary cement (70% cement, 15% P and 15% FA and GGBFS alternatively). Blended cements are tested in terms of flexural strength, compressive strength, bulk density, water absorption, and frost resistance. The results show that although perlite blended cements achieve lower strengths and higher absorptivity compared to conventional additives, they have significant potential for freezing and thawing durability, especially in ternary combination with GGBFS. For practical applications, the intrinsic values of the parameters of the individual binders with perlite (e.g. flexural strength of 4.1–6.2MPa or compressive strength of 18.8–38.5MPa) are sufficient for many practical applications. Perlite, when suitably combined with other pozzolanic materials, can be a suitable component of blended binders.
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6

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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7

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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8

Wang, Xiao Yong, Han Seung Lee, and Ki Bong Park. "Numerical Simulation of Heat Evolution of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model." Materials Science Forum 569 (January 2008): 257–60. http://dx.doi.org/10.4028/www.scientific.net/msf.569.257.

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With the development of concrete industry, the necessity for utilizing waste materials and decreasing overall energy consumption is becoming increasingly obvious. Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry, and concretes made with them can have properties similar to ones made with pure Portland cement at lower cost per unit volume. By using blended Portland cement, both ecology benefit and economic benefit can be achieved. Due to the pozzolanic reaction between calcium hydroxide and blended components, compared with ordinary Portland cement, hydration process of blended Portland cement is more complex. In this paper, based on a multi-component hydration model, a numerical model which can simulate heat evolution process of blended Portland cements is built. The influence of water to cement ratio, curing temperature, particle size distribution of cement paste and blended Portland material, and cement mineral components on heat evolution process is considered. The prediction result agrees well with experiment result.
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9

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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10

Apeh, Abah Joseph. "Hydration Behaviour and Characteristics of Binary Blended Metakaolin Cement Pastes." Journal of Building Materials and Structures 9, no. 1 (April 14, 2022): 57–73. http://dx.doi.org/10.34118/jbms.v9i1.1606.

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Cement production consume large amount of energy to form clinker and carbon dioxide (CO2) emitted into the atmosphere causing global warming. To mitigate this challenge, the use of Metakaolin (MK) as supplementary cementitious material cannot be over emphasized. This study evaluated the use of Metakaolin (MK) on hydration development of MK--PC blended cements and strength of Mortars. The MK with a Blaine fineness of 7883 cm2/g was used to replace Portland Cement (PC) at a level of 0, 5, 10, 15, 20, 25 and 30 % by mass of PC at a constant w/b ratio of 0.50 to prepare blended cements. Hydration development of blended cement and compressive strength of Mortars were investigated using chemically bond water and free-lime contents and strength tests respectively. X – Ray diffraction (XRD) and scanning electron Microscopy (SEM) techniques were also utilised in the analysis of Pozzolanic reaction and hydration products. Test results indicates that Water of consistency, setting times for the mixes increased with increase in MK contents, influence of MK on the chemically bond water and free Lime contents of the blended cements were due to its filler and dilution effects and Pozzolanic reaction. The cumulative non-evaporable water and free-lime contents increased by partial replacement of PC with MK due to PC hydration and Pozzolanic reaction. The tested Mortar prepared with blended cements with 30 % PC replacement with MK shows a retardation of strength development with a low value at early ages (7 days) and increased in growth at later ages (28 days). The compressive strength of tested mortar for 90 days curing age for the blended mortar is 31 N/mm2 close to that of control Mortar (35 N/mm2). The results obtained from XRD and SEM analysis indicated increase in Calcium Hydroxide (CH) consumption and Calcium Silicate hydrate (C-S-H) formation in blended cement pastes with curing time. The PC replacement with MK induced changes in Microstructures of blended cement paste and chemical composition of hydration products. These results are potentials for modelling the behaviour of MK-PC blended cements.
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11

Wang, Xiao Yong, Han Seung Lee, and Seung Min Lim. "Numerical Simulation of Autogenous Shrinkage of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model." Materials Science Forum 569 (January 2008): 261–64. http://dx.doi.org/10.4028/www.scientific.net/msf.569.261.

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Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry. Due to excellent durability, low heat of hydration, energy-saving, resource-conserving, and generally less expensive than ordinary Portland cement, blends Portland cements is used increasingly in construction industry. Both ecology benefit and economic benefit can be achieved by using blended Portland cement. Addition of blended components to cement, especially such as fly ash or silica fume, will lead to a densification of the microstructure. The autogenous shrinkage deformation will increase and the following autogenous shrinkage crack will do harm to durability of concrete structure. In this paper, based on the multi-component hydration model, a numerical program is built to predict autogenous shrinkage of ordinary Portland cement and blended Portland cement. The numerical program considers the influence of water to cement ratio, curing temperature, particle size distribution, cement mineral components on hydration process and autogenous shrinkage. The prediction result agrees well with experiment result.
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12

Sanytsky, Myroslav, Tetiana Kropyvnytska, Hanna Ivashchyshyn, and Оksana Rykhlitska. "Eco-efficient blended cements with high volume supplementary cementitious materials." Budownictwo i Architektura 18, no. 4 (March 20, 2020): 005–14. http://dx.doi.org/10.35784/bud-arch.816.

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The ways of reducing CO2 emissions in the cement industry were analysed for the purposes of implementation of the low carbon development strategy. The optimal solution to this problem is the technologically optimised blended cements with high volume of supplementary cementitious materials of various genesis and fineness. The design of eco-friendly blended cements was achieved by a synergistic combination of the main constituents such as granulated blast furnace slag, superfine zeolite, fly ash and limestone, as well as by optimisation of the their granulometric composition, taking into account their bimodal particle size distribution by volume and surface area. Moreover, the article presents the technical, environmental and economic benefits of using eco-efficient blended cements.
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13

Orogbade, B. O., and A. A. Raheem. "Chemical and Physical Characteristics of Blended Cements Produced from Softwood Ash." LAUTECH Journal of Civil and Environmental Studies 1, March 2018 (March 1, 2018): 1–7. http://dx.doi.org/10.36108/laujoces/8102/10(0110).

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In an attempt to convert agricultural residue to alternative binding material for use in construction industry, this research considered the use of wood ash from Anacardium- occidentale (kaju) wood which is softwood as a pozzolan in cement production. In this study, the chemical composition (silica (SiO.), aluminum oxide (AI,O,), ferric oxide (Fe,O,), calcium oxide (CaQ), magnesium oxide (MgO), sulphur trioxide (SO,), sodium oxide (Na,O) and potassium Oxide (K,O)) of the ashes and the clinker was investigated. The production of blended cements were carried out in the factory by replacing 5- 50% by weight of Ordinary Portland Cement Clinker with the ashes during the manufacturing process. The cement without wood ash serves as the control. The physical characteristic (fineness, initial and final setting times, heat of hydration and residue on 45um sieve), and the chemical composition of the blended cements were also investigated. The results showed that Anacardiumoccidentale ash (AOA) was a suitable material for use as pozzolan since it satisfied the requirement for such a material by having a combined SiO, Fe,O,and Al,O,of more than 70% according to ASTM C 618. The AOA blended cements satisfied standard requirements for up to 20% replacement level. It was concluded that the wood ash was suitable for use in the production of blended cements.
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14

Soltanzadeh, Fatemeh, Ali E. Behbahani, Eduardo N. B. Pereira, and Carlos A. Teixeira. "A Life-Cycle Approach to Integrate Environmental and Mechanical Properties of Blended Cements Containing Seashell Powder." Sustainability 13, no. 23 (November 26, 2021): 13120. http://dx.doi.org/10.3390/su132313120.

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The adverse consequences of producing ordinary Portland cement (OPC) on the environment have introduced cement production as the fourth largest source of anthropogenic carbon emissions after petroleum, coal, and natural gas. Managing and reducing the environmental concerns regarding the impacts of cement production on the environment, namely the depletion of non-renewable fuel resources, consumption of natural raw materials, and releasing huge amounts of CO2 into the atmosphere should be, therefore, one of the key priorities of the cement industry. Application of locally available minerals and wastes that can be blended with OPC as a substitute could considerably reduce the environmental impact. The present study evaluates the potentiality of waste seashell to be used as an additive in the production of blended cement through a modified life cycle approach integrating environmental and mechanical performances. In this regard, 34 cements consisting of different blends of OPC, seashell powder (within the range of 4–30% by OPC mass), and natural pozzolan (up to 30% by OPC mass) were tested to identify the optimal dosage of OPC substitution. Environmental impacts of the cements were assessed through life-cycle analysis. The possibility of mitigating the carbon dioxide emissions in the production of cements, with similar mechanical performance compared to that of OPC, was evaluated by considering both the mechanical and environmental results. The outcome of this study introduced more environment-friendly and sustainable options for future cements.
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15

Sanytsky, Myroslav, Tetiana Kropyvnytska, Stanislav Fic, and Hanna Ivashchyshyn. "Sustainable low-carbon binders and concretes." E3S Web of Conferences 166 (2020): 06007. http://dx.doi.org/10.1051/e3sconf/202016606007.

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Sustainable development depends on a consistency of interests, social, ecological and economic, and that the interests are evaluated in a balanced manner. In order to reduce CO2 emissions, the conception of decreasing clinker factor and increasing the role of supplementary cementitious materials (SCMs) in the cementitious materials has high economical and environmental efficiency. The performance of clinkerefficient blended cements with supplementary cementitious materials were examined. The influence of superfine zeolite with increased surface energy on the physical and chemical properties of low-carbon blended cements is shown. Increasing the dispersion of cementitious materials contributes to the growth of their strength activity index due to compaction of cement matrix and pozzolanic reactions in unclincker part. In consequence of the early structure formation and the directed formation of the microstructure of the cement matrix is solving the problem of obtaining clinker-efficient concretes. Shown that low-carbon blended cements with high volume of SCMs are suitable, in principle, for producing structural concretes.
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16

Aramburo, Carlos H., César Pedrajas, and Rafael Talero. "Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability." Materials 13, no. 18 (September 22, 2020): 4206. http://dx.doi.org/10.3390/ma13184206.

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Calcined clay has become the supplementary cementitious materials with the greatest potential to reduce the clinker/cement. In this research, the mechanical strengths and sulphate resistance of blended cements with a high content of calcined clay as a pozzolanic addition were evaluated to demonstrate that these cements could be designed as CEM (cement) type IV/A-SR and IV/B-SR cements by the current European standard UNE-EN 197-1: 2011. The blended cements were prepared by two Portland cements (P1 and PY6) with different mineralogical compositions and a calcined clay. The level of replacement was greater than 40% by weight. The results obtained confirm the decrease in the mechanical strengths and the increase in the sulfate resistance of the two Portland cements when they are replaced by calcined clay at a level of replacement greater than 40%. These results are a consequence of the chemical effect from the pozzolanic activity of the calcined clay. Therefore, there is an important decrease in portlandite levels of paste liquid phase that causes the increase in sulfate resistance and the decrease of the mechanical strengths.
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17

Kirgiz, Mehmet Serkan. "Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/625350.

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Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement.
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18

Akgün, Yasemin, and Talha Yılmaz. "The Heat Storage Capacities of Mortars Containing Clinoptilolite Blended Cements." Academic Perspective Procedia 2, no. 3 (November 22, 2019): 758–67. http://dx.doi.org/10.33793/acperpro.02.03.83.

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Recently, the studies on the heat storage capabilities of building materials for energy efficient building design are becoming more widespread. In this study, the heat storage capacities of mortars produced with blended cement containing clinoptilolite that is the most valuanle of the natural zeolite minerals were investigated. The clinoptilolite which is used as replacement material and has the highest purity rate (96% purity) in the world was obtained from Manisa-Gördes region. Firstly, the mortar samples containing clinoptilolite blended cements at 0, 10, 30 and 50% replacement ratios were produced. And then, the physical, chemical, mechanical, petrographic properties, thermal conductivity and heat storage capacities of clinoptilolite rock were determined. The compressive strengths and thermal performance tests were performed on the mortar samples containing clinoptilolite blended cements. The test results were compared amongst themselves and with each other. According to the test results, it was concluded that heat storage capabilities of the mortars containing clinoptilolite blended cements could be improved.
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19

Rahhal, Viviana Fátima, Mónica Adriana Trezza, Alejandra Tironi, Claudia Cristina Castellano, Milena Pavlíková, Jaroslav Pokorný, Edgardo Fabian Irassar, Ondřej Jankovský, and Zbyšek Pavlík. "Complex Characterization and Behavior of Waste Fired Brick Powder-Portland Cement System." Materials 12, no. 10 (May 21, 2019): 1650. http://dx.doi.org/10.3390/ma12101650.

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Two waste fired brick powders coming from brick factories located in Argentine and Czech Republic were examined as alternative mineral admixtures for the production of blended cements. In pastes composition, local Portland cements (Argentine and Czech) were substituted with 8–40%, by mass, with powdered ceramic waste. For the ceramic waste-Portland cement system, workability, the heat released, pozzolanity, specific density, compressive strength, hydrated phases, porosity, and pore size distribution were tested. The relevance of the dilution effect, filler effect, and pozzolanic activity was analyzed to describe the general behavior of the pozzolan/cement system. The properties and performance of cement blends made with finely ground brick powder depended on the composition of ceramic waste and its reactivity, the plain cement used, and the replacement level. Results showed that the initial mini-slump was not affected by a low ceramic waste replacement (8% and 16%), and then it was decreased with an increase in the ceramic waste content. Brick powder behaved as a filler at early ages, but when the hydration proceeded, its pozzolanic activity consumed partially the calcium hydroxide and promoted the formation of hydrated calcium aluminates depending on the age and present carbonates. Finally, blended cements with fired brick powder had low compressive strength at early ages but comparable strength-class at later age.
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20

Mehta, P. Kumar. "Blended cements in construction." Cement and Concrete Composites 14, no. 3 (January 1992): 223–24. http://dx.doi.org/10.1016/0958-9465(92)90016-o.

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21

Sancak, Emre, and Şükrü Özkan. "Sodium Sulphate Effect on Cement Produced with Building Stone Waste." Journal of Materials 2015 (May 7, 2015): 1–12. http://dx.doi.org/10.1155/2015/813515.

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In this study, the blended cements produced by using the building stone waste were exposed to sulphate solution and the cement properties were examined. Prepared mortar specimens were cured under water for 28 days and then they were exposed to three different proportions of sodium sulphate solution for 125 days. Performances of cements were determined by means of compressive strength and tensile strength tests. The broken parts of some mortar bars were examined with scanning electron microscope (SEM). Besides, they were left under moist atmosphere and their length change was measured and continuously monitored for period of 125 days. In blended cements, solely cements obtained by replacing 10–20% of diatomites gave similar strength values with ordinary Portland cement (CEM I 42.5R) at the ages of 7, 28, and 56 days. In all mortar specimens that included either waste andesite (AP) or marble powder (MP) showed best performance against very severe effective sodium sulphate solutions (13500 mg/L).
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22

Marroccoli, Milena, and Antonio Telesca. "The Influence of Chemical Activators on the Hydration Behavior and Technical Properties of Calcium Sulfoaluminate Cements Blended with Ground Granulated Blast Furnace Slags." Buildings 11, no. 7 (June 24, 2021): 268. http://dx.doi.org/10.3390/buildings11070268.

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The manufacture of Ordinary Portland cement (OPC) generates around 8% of the global CO2 emissions related to human activities. The last 20 years have seen considerable efforts in the research and development of methods to lower the carbon footprint associated with cement production. Specific focus has been on limiting the use of OPC and employing alternative binders, such as calcium sulfoaluminate (CSA) cements, namely special hydraulic binders obtained from non-Portland clinkers. CSA cements could be considered a valuable OPC alternative thanks to their distinctive composition and technical performance and the reduced environmental impact of their manufacturing process. To additionally reduce CO2 emissions, CSA cements can also be blended with supplementary cementitious materials. This paper investigates the influence of two separately added chemical activators (NaOH or Na2CO3) on the technical properties and hydration behavior of four CSA blended cements obtained by adding to a plain CSA cement two different ground granulated blast furnace slags. Differential thermal-thermogravimetric, X-ray diffraction and mercury intrusion porosimetry analyses were done, along with shrinkage/expansion and compressive strength measurements.
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23

Thomas, Michael, Laurent Barcelo, Bruce Blair, Kevin Cail, Anik Delagrave, and Ken Kazanis. "Lowering the Carbon Footprint of Concrete by Reducing Clinker Content of Cement." Transportation Research Record: Journal of the Transportation Research Board 2290, no. 1 (January 2012): 99–104. http://dx.doi.org/10.3141/2290-13.

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Significant efforts have been made to reduce carbon dioxide (CO2) emissions associated with the manufacture of portland cement, primarily by making the process more energy efficient and increasing the use of alternative fuels. Further reductions in CO2 can be achieved by lowering the clinker component of the cement because the pyroprocessing used to manufacture clinker produces approximately 1 tonne of CO2 for every tonne of clinker. Traditionally reductions in the clinker content of cement have been achieved by producing blended cement consisting of portland cement combined with a supplementary cementing material (SCM). In Canada, it is now permitted to intergrind up to 15% limestone with cement clinker to produce portland limestone cement or blended portland limestone cement. Recent trials were conducted at the Brookfield cement plant in Nova Scotia to evaluate the performance of a blended cement containing 15% ground, granulated blast furnace slag (an SCM) with that of a blended portland limestone cement containing the same amount of slag plus 12% interground limestone. Performance was evaluated by the construction of a section of concrete pavement using concrete mixtures produced with the two cements and various amounts of fly ash (another SCM). A wide range of laboratory tests were performed on the concrete specimens cast on site during the placement of the concrete pavement. The results indicated that the cements were of equivalent performance.
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Telesca, Antonio, Neluta Ibris, and Milena Marroccoli. "Use of Potabilized Water Sludge in the Production of Low-Energy Blended Calcium Sulfoaluminate Cements." Applied Sciences 11, no. 4 (February 13, 2021): 1679. http://dx.doi.org/10.3390/app11041679.

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Ordinary Portland cement (OPC) manufacture determines about 8% of the global anthropogenic CO2 emissions. This has led to both the cement producers and the scientific community to develop new cementitious materials with a reduced carbon footprint. Calcium sulfoaluminate (CSA) cements are special hydraulic binders from non-Portland clinkers; they represent an important alternative to OPC due to their peculiar composition and significantly lower impact on the environment. CSA cements contain less limestone and require lower synthesis temperatures, which means a reduced kiln thermal energy demand and lower CO2 emissions. CSA cements can also be mixed with supplementary cementitious materials (SCMs) which further reduce the carbon footprint. This article was aimed at evaluating the possibility of using different amounts (20 and 35% by mass) of water potabilization sludges (WPSs) as SCM in CSA-blended cements. WPSs were treated thermally (TT) at 700° in order to obtain an industrial pozzolanic material. The hydration properties and the technical behavior of two different CSA-blended cements were investigated using differential thermal–thermogravimetric and X-ray diffraction analyses, mercury intrusion porosimetry, shrinkage/expansion and compressive strength measurements. The results showed that CSA binders containing 20% by mass of TTWPSs exhibited technological properties similar to those relating to plain CSA cement and were characterized by more pronounced eco-friendly features.
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Li, Qiu, Andrew D. Deacon, and Nichola J. Coleman. "Iodoform-Blended Portland Cement for Dentistry." Prosthesis 2, no. 4 (October 7, 2020): 277–96. http://dx.doi.org/10.3390/prosthesis2040025.

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Portland cement-based formulations blended with radiopacifying agents are popular endodontic materials for various root filling and pulp capping applications. Iodoform (CHI3) is an alternative candidate radiopacifier whose impact on the setting, bioactivity, antimicrobial properties and cytotoxicity of white Portland cement were evaluated in this study. Isothermal conduction calorimetry and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) showed that 20 wt% iodoform had no significant impact on the kinetics of cement hydration with respect to the formation of the major calcium silicate hydrate (C-S-H) gel product (throughout the 28-day observation). Conversely, transmission electron microscopy demonstrated that iodine was incorporated into the ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O) product phase. Both iodoform-blended and pure Portland cements exhibited comparable biocompatibility with MG63 human osteosarcoma cells and similar bioactivity with respect to the formation of a hydroxyapatite layer upon immersion in simulated body fluid. By virtue of their high alkalinity, both cements inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. However, in all cases, iodoform enhanced the antimicrobial effect and significantly reduced the minimum bactericidal concentration of the cement. In conclusion, iodoform offers antimicrobial advantages in Portland cement-based formulations where oral biofilm formation threatens the success of root filling materials and dentine substitutes. The reactivity with the calcium aluminosulfate components of the hydrating cement matrix warrants further research to understand the long-term stability of the cement matrix in the presence of iodoform.
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Ez-zaki, H., A. Diouri, M. Maher, A. Aidi, and T. Guedira. "Effect of mechanical activation of fly ash added to Moroccan Portland cement." MATEC Web of Conferences 149 (2018): 01074. http://dx.doi.org/10.1051/matecconf/201814901074.

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Nowadays, the cement industry is the largest emitter of CO2. In 2015, cement production accounts for roughly 8% of global CO2 emissions. In order to reduce this impact, cement plants are working on alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement. This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.
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Binici, Hanifi, Joselito Arocena, Selim Kapur, Orhan Aksogan, and Hasan Kaplan. "Microstructure of red brick dust and ground basaltic pumice blended cement mortars exposed to magnesium sulphate solutions." Canadian Journal of Civil Engineering 36, no. 11 (November 2009): 1784–93. http://dx.doi.org/10.1139/l09-103.

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This paper presents a laboratory study on the deterioration of blended cement combinations of plain Portland cement (PPC) with red brick dust (RBD) and ground basaltic pumice (GBP). The compressive strength and the magnesium sulphate resistance of cements have been experimentally determined. The development of the microstructure and the secondary minerals in the plain and blended cements were studied via scanning electron microscope (SEM) analysis. A series of mechanical tests of cement mortars were undertaken on all specimens. A large quantity of sheet-like C-S-H was found in the mortars that have developed by the addition of RBD and GBP. The results indicated that the increase in the additive content caused a significant increase in the sulphate resistance of the mortars. Hence, the studied RBD and GBP can be recommended for use as admixtures in cement production.
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Pavlík, Zbyšek, Milena Pavlíková, Jan Fořt, Martina Záleská, Igor Medveď, Robert Černý, and Petros G. Koutsoukos. "Application of Thermally Treated Sewage Sludge in Blended Cements." Advanced Materials Research 905 (April 2014): 191–94. http://dx.doi.org/10.4028/www.scientific.net/amr.905.191.

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Chemical, physical, morphological, and mineralogical analysis of sewage sludge originating from a waste water treatment plant in Patras, Greece, is presented in the paper. The sewage sludge is firstly dried at 70°C, then oven-burned at 700°C for two hours and milled. The thermally treated material is analyzed using XRF and XRD, the particle size distribution is determined by a laser diffraction method. A potential use of sewage sludge in blended cements is investigated on the basis of the measurement of mechanical and basic physical properties of pastes containing the sludge in an amount of up to 60% of the mass of cement. Experimental results show that the thermal treatment of pre-dried sewage sludge and its grinding provides a material that can be successfully applied as a partial replacement of Portland cement. At a production of blended cements for high strength concrete, an up to 20% cement replacement level can be recommended.
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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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Caneda-Martínez, Laura, Manuel Monasterio, Jaime Moreno-Juez, Sagrario Martínez-Ramírez, Rosario García, and Moisés Frías. "Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes." Materials 14, no. 5 (March 8, 2021): 1299. http://dx.doi.org/10.3390/ma14051299.

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This work analyses the influence of fine concrete fractions (<5 mm) of different natures —calcareous (HcG) and siliceous (HsT)—obtained from construction and demolition waste (C&DW) on the behaviour of blended cement pastes with partial replacements between 5 and 10%. The two C&DW fractions were characterised by different instrumental techniques. Subsequently, their lime-fixing capacity and the physico-mechanical properties of the blended cement pastes were analysed. Lastly, the environmental benefits of reusing these fine wastes in the manufacture of future eco-efficient cement pastes were examined. The results show that HsT and HcG exhibit weak pozzolanic activity, owing to their low reactive silica and alumina content. Despite this, the new cement pastes meet the physical and mechanical requirements of the existing regulations for common cements. It should be highlighted that the blended cement pastes initially showed a coarser pore network, but then they underwent a refinement process between 2 and 28 days, along with a gain in compressive strength, possibly due to the double pozzolanic and filler effect of the wastes. The environmental viability of the blended cements was evaluated in a Life Cycle Assessment (LCA) concluding that the overall environmental impact could be reduced in the same proportion of the replacement rate. This is in line with the Circular Economy goals and the 2030 Agenda for Sustainable Development.
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31

Raheem, Akeem Ayinde, and Mutiu A. Kareem. "Chemical Composition and Physical Characteristics of Rice Husk Ash Blended Cement." International Journal of Engineering Research in Africa 32 (September 2017): 25–35. http://dx.doi.org/10.4028/www.scientific.net/jera.32.25.

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Applications of agricultural by-product as substitute for non-renewable material in cement production are desirable in stimulating socio-economic development. In this study, Rice Husk Ash (RHA) blended cement was produced by replacing 5%, 7%, 11.25%, 15%, 20.25% and 25% by weight of Ordinary Portland Cement (OPC) clinker with RHA. The cement without RHA serves as the control. The chemical compositions of RHA, OPC-clinker and the blended cements were determined using X-ray fluorescence analyzer. The physical characteristics of RHA blended cements that were considered are fineness, soundness, consistency, initial and final setting times and compressive strength at 2, 7, 28, 56 and 90 curing ages. The results showed that RHA is a suitable material for use as a pozzolan as it satisfied the minimum requirement by having the sum of SiO2, Al2O3 and Fe2O3 of more than 70%. Incorporation of RHA led to an increase in the composition of SiO2 and reduction in that of CaO. An increase in RHA content showed a decrease in compressive strength at early ages and slightly increase at a later age (90 days). The blended cement produced with lower levels of RHA replacement conforms to standard specifications specified in BS EN 197-1:2000, NIS 439:2000 and ASTM C 150-02. The minimum Strength Activated Index (SAI) of 75% at the age of 28 days of curing as specified by ASTM C 618 was satisfied by RHA replacement of up to 15%. It was concluded that blended cement with the maximum of 15% RHA content is suitable for use for structural purposes.
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32

Krivenko, Pavel, Myroslav Sanytsky, and Tetiana Kropyvnytska. "Alkali-Sulfate Activated Blended Portland Cements." Solid State Phenomena 276 (June 2018): 9–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.276.9.

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Early strength of the blended Portland cements containing granulated blast furnace slag and natural pozzolanas (zeolite tuff, etc.) can be enhanced by the alkali-sulfate activation. High early strength of the blended Portland cements as a result of alkali-sulfate activation can be attributed to acceleration of pozzolanic reaction at the early stages and formation of more quantities of ettringite at the early stages of structure formation. The results of the study showed that with high amounts of sodium sulfate in the alkali-sulfate activator, contents of gypsum dihydrate as a setting regulator of the blended Portland cements could be reduced. The effect of sodium sulfate activator on properties of the blended Portland cements was studied and the results are discussed.
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33

Guo, Xiaolu, and Huisheng Shi. "Calcium sulfoaluminate (CSA) blended cements." Magazine of Concrete Research 68, no. 4 (February 2016): 208–15. http://dx.doi.org/10.1680/macr.15.00123.

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34

Révay, Miklós. "Dispersion optimization of blended cements." Epitoanyag - Journal of Silicate Based and Composite Materials 56, no. 1 (2004): 4–11. http://dx.doi.org/10.14382/epitoanyag-jsbcm.2004.1.

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35

Singh, N. B., K. N. Bhattacharjee, and A. K. Shukla. "Hydration of portland blended cements." Cement and Concrete Research 25, no. 5 (July 1995): 1023–30. http://dx.doi.org/10.1016/0008-8846(95)00097-v.

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36

Torréns-Martín, D., L. Fernández-Carrasco, and M. T. Blanco-Varela. "Thermal analysis of blended cements." Journal of Thermal Analysis and Calorimetry 121, no. 3 (March 31, 2015): 1197–204. http://dx.doi.org/10.1007/s10973-015-4569-1.

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37

Vereshchagin, V. I., V. N. Smirenskaya, and S. V. Érdman. "Water-resistant blended oxychloride cements." Glass and Ceramics 54, no. 11-12 (December 1997): 368–72. http://dx.doi.org/10.1007/bf02768185.

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38

Miller, E. W. "Blended cements—Applications and implications." Cement and Concrete Composites 15, no. 4 (January 1993): 237–45. http://dx.doi.org/10.1016/0958-9465(93)90027-7.

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39

Ambroise, Jean, Sandrine Maximilien, and Jean Pera. "Properties of Metakaolin blended cements." Advanced Cement Based Materials 1, no. 4 (May 1994): 161–68. http://dx.doi.org/10.1016/1065-7355(94)90007-8.

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40

Kolani, B., L. Buffo-Lacarrière, A. Sellier, G. Escadeillas, L. Boutillon, and L. Linger. "Hydration of slag-blended cements." Cement and Concrete Composites 34, no. 9 (October 2012): 1009–18. http://dx.doi.org/10.1016/j.cemconcomp.2012.05.007.

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41

Gołaszewska, Małgorzata, and Zbigniew Giergiczny. "Study of the Properties of Blended Cements Containing Various Types of Slag Cements and Limestone Powder." Materials 14, no. 20 (October 14, 2021): 6072. http://dx.doi.org/10.3390/ma14206072.

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It is currently vital to use more environmentally friendly cementitious composites, such as blended slag-limestone cements. However, many properties of slag-limestone cements are not yet fully research, especially in regards to the effect of limestone properties on properties of mortars and concrete. In the research, three types of slag cements were mixed with two types of limestone to obtain multi-component slag-limestone cements. Tests of rheological properties, heat of hydration, and compressive strength were conducted to ascertain the effect of limestone on the cement properties and to check the viability of this type of cement for engineering practice. It was found that the addition of up to 10% of limestone to slag cements did not have negative effects on tested properties; however, the exact influence of limestone was dependent on limestone particle size distribution. Increasing the amount of limestone in limestone-slag cements to 15% significantly decreased the compressive strength of the mortars and decreased hydration heat but had no significant effect on rheological properties.
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42

Ji, Guangxiang, Hafiz Asad Ali, Keke Sun, Dongxing Xuan, Xiaoqin Peng, and Jingjun Li. "Volume Deformation and Hydration Behavior of Ordinary Portland Cement/Calcium Sulfoaluminate Cement Blends." Materials 16, no. 7 (March 27, 2023): 2652. http://dx.doi.org/10.3390/ma16072652.

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Blends of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement can be used to adjust the properties of cement for specific applications. In this study, CSA cement was used as a shrinkage-compensating admixture to improve the hydration behavior and performance (compressive strength and drying shrinkage) of OPC; the expansion behavior of the blended cement mortar was evaluate based on the saturation index of ettringite. The experimental results showed that incorporating CSA cement resulted in a delayed effect on the hydration of C3S, shortened the induction periods of the blended cement and decreased the setting time. The CSA cement also improved the early compressive strength and drying shrinkage of the OPC due to its compact microstructure. The drying shrinkage of the OPC mortar decreased by 27.8% when 6% CSA cement was used, but the formation of microcracks due to expansion could negatively impact its late compressive strength development and associated pore structures of the blends when the replacement content of CSA cement exceeded 6 wt.%. The results relevant to the expansion behavior of the CSA cements could induce crystallization stress, enhancing its resistance against shrinkage cracking.
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43

Nigri, Ghania, Yacine Cherait, and Soraya Nigri. "Physical Characterization and Durability of Blended Cements Based on Brick Powder." Civil and Environmental Engineering Reports 30, no. 3 (September 1, 2020): 201–13. http://dx.doi.org/10.2478/ceer-2020-0040.

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Abstract This research work discusses both the physical and durability characteristics of newly blended cement containing waste crushed brick. This waste is used as a partial substitution for clinker in cement. Thus, blended cements are obtained by grinding and homogenizing clinker, waste brick, and gypsum. Four compositions containing 0%, 10%, 20%, and 30% of waste materials were prepared and submitted to various characterization tests. The introduction of brick powder improved the physical characteristics, therefore; it improved the mechanical properties and durability performance of the new cement compared to the reference, prepared with 0% addition. More particularly, it resisted sulfuric acid (H2SO4) attack after fixation of portlandite by pozzolan.
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44

Boubekeur, Toufik, Bensaid Boulekbache, Mohamed Salhi, Karim Ezziane, and EL Hadj Kadri. "Beneficial Effect of Incorporation of Slag on the Hydration Heat, Mechanical Properties and Durability of Cement Containing Limestone Powder." MATEC Web of Conferences 330 (2020): 01047. http://dx.doi.org/10.1051/matecconf/202033001047.

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This paper presents the experimental results of a wide research program, tending to determine the hydration mechanism, mechanical properties and the durability performance of ternary cement containing limestone powder and slag. The limestone powder increase the hydration at early ages inducing a high strength at, but it can reduce the later strength due to the dilution effect. On the other hands, Slag (S) contributes to increase the compressive strength at later ages. Hence, at medium blended cement (OPC-LP-S) with better performance could be produced. Results show at later age the Slag is very effective in producing ternary blended cements with similar on higher compressive strength than the ordinary Portland cement at 28 and 90 days. For durability, the incorporation of the slag into the cement containing limestone powder improves remarkably resistance to attack by acids and sulfates and it has been found that the durability of the cements never depends on the mechanical strength.
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Wongkeo, Watcharapong, Pailyn Thongsanitgarn, and Arnon Chaipanich. "Compressive Strength of Binary and Ternary Blended Cement Mortars Containing Fly Ash and Silica Fume under Autoclaved Curing." Advanced Materials Research 343-344 (September 2011): 316–21. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.316.

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Cement industry is a one of the major sources of environmental pollution therefore the reduction of cement demand should be improved. Fly ash and silica fume is a by-product of industries and it should be reused to reduce the waste pollution. Thus, this study investigated the use of fly ash and silica fume as a cement replacement in binary and ternary blended cements on compressive strength and physical properties of mortar. Autoclaved curing at 130 °C and 20 psi of pressure for 9 h was used in this study. The results show that the compressive strength of binary blended cement mortar with FA tends to decrease with increased FA replacement and shows compressive strength lower than PC control. However, compressive strength of binary blended cement mortar with SF was improved and shows compressive strength higher than that of PC control. The compressive strength of ternary blended cement mortar was higher than binary blended cement at the same level replacement and it increases with increased SF replacement. Moreover, ternary blended cement mortar containing 10%SF by weight contribute in giving compressive strength higher than PC control. The incorporation of FA with SF can enhance workability of blended cement mortar containing only SF replacement.
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46

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

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AbstractThis study investigates the effects of seawater and nanosilica (3% by weight of cement), on the fresh and hardened properties of cement pastes and mortars produced with two types of low heat cements: Portland pozzolana cement (CEM II) and blast furnace cement (CEM III). The heat of hydration, initial and final setting times, rheological properties, strength development, sorptivity and water accessible porosity of the cement pastes and mortars were determined. The data reveal that cement type has a significant effect on the reaction rate of cement with seawater and nanosilica (NS). Specimens produced with slag-blended cement exhibited a higher cement reaction rate and the composite produced exhibited better mechanical performance, as a result of the additional reaction of alumina rich phases in slag, with seawater. Replacement of freshwater with seawater contributes mostly to a significant improvement of early strength. However, in the case of slag-blended cement, 28 day strength also improved. The incorporation of NS results in additional acceleration of hydration processes, as well as to a decrease in cement setting time. In contrast, the addition of NS results in a noticeable increment in the yield-stress of pastes, with this effect being pronounced when NS is mixed along with seawater. Moreover, the use of seawater and NS has a beneficial effect on microstructure refinement, thus improving the transport properties of cement mortars. Overall, the study has showed that both seawater and NS can be successfully used to accelerate the hydration process of low heat blended cements and to improve the mechanical and transport properties of cement-based composites.
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Ermilova, Elizaveta, and Zagira Kamalova. "The influence of calcined mixture cooling method on hydration products composition of blended cement stone." E3S Web of Conferences 274 (2021): 04011. http://dx.doi.org/10.1051/e3sconf/202127404011.

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Complex additives based on combinations of calcined clays, including kaolinite with limestone, due to the synergetic effect play a major role in the creation of blended cements. Usually carbonate rocks contain clay impurities with adverse effects on the properties of the resultant cements and concretes. At the same time calcium carbonate contained in marl clays during calcination allows getting high-quality pozzolanic material. The effective complex additive based on the calcined mixture of clay and limestone was created. The aim of the study is to determine the effect of fast and slow cooling methods of the artificial mixture after calcination on the hydration products composition of blended cement stone with complex additives of calcined mixtures of clays and carbonates. Obtained results allow determining the conditions for obtaining effective complex additives based on calcined mixtures of ubiquitous clays and carbonate rocks for their application in blended Portland cement, and thus to expand the range of the latter. It is found that the preferred method is the fast cooling of the resulting mixture, which contributes to obtaining a complex additive with higher pozzolanic properties, compared with the additive obtained by the slow cooling method.
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48

García Giménez, Rosario, Raquel Vigil de la Villa Mencía, Moises Frías, Sagrario Martínez Ramírez, Iñigo Vegas Ramiro, and Lucía Fernández Carrasco. "Cements based on kaolinite waste." Advances in Geosciences 45 (August 10, 2018): 133–38. http://dx.doi.org/10.5194/adgeo-45-133-2018.

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Abstract. The cement industry involves high-energy consumption that generates high CO2 emissions into the atmosphere. Environmental concerns can be addressed by replacing parts of Portland cement clinkers with pozzolanic materials in mortars and concrete. Slag, fly ash and silica fume are materials considered for the planned replacement. Research studies on clay minerals, such as kaolinite, are being followed with special attention by the scientific community and the cement industry. It is well known that these minerals require an activation process to transform kaolinite (K) into metakaolinite (MK). MK is an amorphous material from the transformation of K with high pozzolanic activity, which is its capacity to react with the portlandite released during the hydration of Portland cement, generating compounds such as C–S–H gels and some aluminum-phase hydrates. One of the MK production methods is heat treatment controlled by kaolinite at temperatures in the range of 600–900 ∘C. Different residues have been used (coal mining, paper sludge and waste from a drinking water treatment plant) activated at 600 ∘C for 2 h to elaborate blended cements. Due to their good behaviour as future eco-efficient additions, this research is a study by x-ray fluorescence (XRF), x-ray diffraction (XRD) and scanning electron microscopy (SEM) of their influence on the performances of blended cement mixtures (binary and ternary one), with substitutions of pozzolan ratio at 28 days of hydration. The porosity of pozzolanic cements decreases because of the formation of hydrated phases during pozzolanic reaction.
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Halbiniak, Jacek, Jacek Katzer, Maciej Major, and Izabela Major. "A Proposition of an In Situ Production of a Blended Cement." Materials 13, no. 10 (May 15, 2020): 2289. http://dx.doi.org/10.3390/ma13102289.

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Many byproducts and waste materials with pozzolanic properties can substitute natural raw materials in cement production. Some of these waste materials like fly ash and blast furnace slag are commonly harnessed by cement industry. Others are of seldom use due to limitations of the very centralized cement production systems currently in use. In the authors opinion, it is necessary to change this system to enable efficient utilization of various waste materials that are available locally (e.g., white and red ceramics). In this study, a new partially centralized system of cement production is proposed. The adoption of a new system would significantly reduce the volume of long-distance transportation and enable utilization of numerous locally available waste materials that are currently dismissed. The last stage of production of the ready-to-use cement would take place in situ. The cement would be produced on demand and be immediately used for concrete production on-site. The research program was conducted considering the importance of the quality of cements obtained in the new way, substituting up to 12% of its mass by white ceramics. The research program was proof of concept of the proposed cement production system. It was shown that the quality of “in situ cement” does not differ from standard cements.
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Marchetti, Guillermina, Antonella Di Salvo Barsi, Viviana Rahhal, and Egdardo Irassar. "Particles spasing of supplementary cementitious materials in binary blended cements." Cement Wapno Beton 26, no. 5 (2021): 366–78. http://dx.doi.org/10.32047/cwb.2021.26.5.1.

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The effect of limestone filler [LF], dolomite filler [DF], metakaolin [MK], and metaillite [MI] additives on the packing density of the binary blended cements were studied using of the water film thickness [WFT] and the optimal water demand [OWD]. The influence of these supplementary cementitious materials [SCM] on the flowability of cement pastes and mortars was analyzed and the compressive strength of mortars was discussed. The results indicate that the incorporation of these SCM on the packing density is highly related to the particle size distribution and the optimal addition of SCM to the blended cements, assures maximum packing density. The effects on flowability not only depend on packing density but of the surface area of particles and the addition of SCM enhance the compressive strength of the mortars.
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