The Experts below are selected from a list of 6366 Experts worldwide ranked by ideXlab platform
Robert Cerný - One of the best experts on this subject based on the ideXlab platform.
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application of ceramic powder as Supplementary Cementitious Material in lime plasters
Materials Science, 2016Co-Authors: Monika Cachova, Martin Keppert, Eva Vejmelkova, Dana Koňakova, Jaromir žumar, Pavel Reiterman, Robert CernýAbstract:In this paper, the properties of plasters based on lime – brick powder binder of varying composition (ceramics content from 0 to 80 %) are studied. The plasters are prepared with a constant water amount. The pore size distribution is thus influenced in a positive way; the total porosity increases with the ceramics content but the volume of capillary pores is reduced. It results in lower water vapor diffusion resistance factor while the apparent moisture diffusivity coefficient increases just moderately. The influence of ceramic on strength of plasters is not found very important. The thermal conductivity of plasters containing ceramics is lower than those with the pure lime what is again in agreement with the pore size distribution. It can be concluded that fine brick powder can be used as pozzolanic admixture in lime based plasters with a positive influence on its functional parameters. DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7433
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simultaneous dsc and tg analysis of high performance concrete containing natural zeolite as a Supplementary Cementitious Material
Journal of Thermal Analysis and Calorimetry, 2015Co-Authors: Lenka Scheinherrova, Anton Trnik, Igor Medveď, Robert CernýAbstract:Natural zeolite is a pozzolan active Material used as a Supplementary Cementitious Material to improve the final properties of concrete. In this paper, the thermal properties of hardened high-performance concrete containing natural zeolite in the amount varying from 0 to 60 mass % of the cement binder are studied. Using the differential scanning calorimetry and thermogravimetry, the hydration and pozzolanic reaction in the concrete are investigated in dependence on the amount of the added natural zeolite. The investigation is performed in the temperature range from 25 to 1000 °C with a rate 5 °C min−1 in an argon atmosphere. We found out that the temperature and enthalpy of liberation of physically bound water, C–S–H gels, and ettringite decomposition (all occurring from 50 to 300 °C) almost do not change with an amount of the natural zeolite in the studied samples. On the other hand, for portlandite (420–510 °C) and calcite decomposition (580–800 °C), they decrease with an amount of the natural zeolite. Finally, the last modification at temperature about 857 °C was attributed to the crystallization of wollastonite.
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engineering properties of concrete containing natural zeolite as Supplementary Cementitious Material strength toughness durability and hygrothermal performance
Cement & Concrete Composites, 2015Co-Authors: Eva Vejmelkova, Tereza Kulovaná, Martin Keppert, Dana Koňakova, Jaromir žumar, Pavla Rovnanikova, Zbyněk Kersner, Martin Sedlmajer, Robert CernýAbstract:Abstract A complex analysis of engineering properties of concrete containing natural zeolite as Supplementary Cementitious Material in the blended Portland-cement based binder in an amount of up to 60% by mass is presented. The studied parameters include basic physical characteristics, mechanical and fracture–mechanics properties, durability characteristics, and hygric and thermal properties. Experimental results show that 20% zeolite content in the blended binder is the most suitable option. For this cement replacement level the compressive strength, bending strength, effective fracture toughness, effective toughness, and specific fracture energy are only slightly worse than for the reference Portland-cement concrete. The frost resistance, de-icing salt resistance, and chemical resistance to MgCl2, NH4Cl, Na2SO4, and HCl are improved. The hygrothermal performance of hardened mixes containing 20% natural zeolite, as assessed using the measured values of water absorption coefficient, water vapor diffusion coefficient, water vapor sorption isotherms, thermal conductivity, and specific heat capacity, is satisfactory.
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mechanical and thermal properties of moderate strength concrete with ceramic powder used as Supplementary Cementitious Material
Advanced Materials Research, 2014Co-Authors: Eva Vejmelkova, Tereza Kulovaná, Dana Koňakova, Adam Hubacek, Robert CernýAbstract:The possibilities of utilisation of ceramic powder as Supplementary Cementitious Material are the matter of the presented study. The finely ground ceramic powder originates from the grinding process of thermal insulating brick blocks and shows pozzolanic properties. For the determination of its influence on concrete properties, five mixtures with different percentages of cement replaced by ceramics are designed. The bulk density as well as matrix density are found to decrease with the increasing dosage of waste ceramic Material, while the open porosity increases. The compressive strength exhibits a small decrease with the growing amount of cement replacement. The measurement of thermal conductivity shows that by adding ceramic powder the thermal insulating abilities of studied concrete are improved.
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waste ceramics as Supplementary Cementitious Material characterization and utilization
Applied Reconfigurable Computing, 2014Co-Authors: Martin Keppert, Milena Pavlikova, Jaromir žumar, Anton Trnik, Monika Cachova, Robert CernýAbstract:Materials containing thermally treated clay minerals are well known for their pozzolanity, i.e. ability to react with calcium hydroxide to cementing compounds. Finely ground ceramics have been used as pozzolan since ancient times and nowadays they again attracts attention because of the current effort to utilize waste as secondary raw Material. Contrary to other pozzolans (fly ash, metakaolin etc.) ceramics contain not only a reactive phase but also a certain amount of crystalline minerals which do not take part in the hydration process. The paper deals with finely ground ceramic powder generated during production of brick blocks.
Hjh Jos Brouwers - One of the best experts on this subject based on the ideXlab platform.
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evaluation of municipal solid waste incineration filter cake as Supplementary Cementitious Material
Construction and Building Materials, 2020Co-Authors: V Caprai, K Schollbach, M V A Florea, Hjh Jos BrouwersAbstract:Abstract Worldwide, the incineration of household waste generates high amounts of Municipal Solid Waste Incineration (MWSI) bottom ashes (BA). In some European countries, the Filter Cake (FC) is also collected (below 0.25 mm) by the wet sieving treatment of coarse BA (4–32 mm). By using centrifugation, the presence of readily soluble contaminants in FC is decreased. In addition, for reducing the leaching of heavy metals the use of FC in combination with cement represents a valuable option, due to cement immobilization capacity and the FC appropriate particle size and chemical composition. However, to the best of the authors’ knowledge, FC has not often investigated as binder replacement. Therefore, this paper addresses the suitability of FC as substitution for CEM I 52.5 R, between 1 and 20% replacement, by mass. Due to its porous structure, the FC lowers the bulk and particle density of the mixtures and increases the water demand, and widens the particle size distribution. The XRD analysis evidences the formation of layered double hydroxides (LDH) in the early stage of the reaction (1, 2, 7 days) incorporating contaminants as Cl. Kinetically, the hydration of C3S is delayed according to the FC replacement without affecting the long-term flexural strength. Despite this, the presence of FC minimally contributes to the increase of cement reaction degree. Tested accordingly to the EN 124-57, the 28 days mortars fulfill the Dutch legislation for contaminants leaching as unshaped Material, independently on the substitution rate.
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photovoltaic s silica rich waste sludge as Supplementary Cementitious Material scm
Cement and Concrete Research, 2013Co-Authors: George G Quercia, Van Der Jjg Putten, Gotz G Husken, Hjh Jos BrouwersAbstract:Abstract Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO 2 and CaCO 3 . This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 μm. Thus, this sludge constitutes a potentially hazardous waste when it is improperly disposed. Due to its high content of amorphous SiO 2 , this sludge has a potential use as Supplementary Cementitious Material (SCM) in concrete. In this study the main properties of three different samples of photovoltaic's silica-rich waste sludge (nSS) were physically and chemically characterized. The characterization techniques included: scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen physical adsorption isotherm (BET method), density by Helium pycnometry, particle size distribution determined by laser light scattering (LLS) and zeta-potential measurements by dynamic light scattering (DLS). In addition, a dispersability study was performed to design stable slurries to be used as liquid additives for the concrete production on site. The effects on the hydration kinetics of cement pastes by the incorporation of nSS in the designed slurries were determined using an isothermal calorimeter. A compressive strength test of standard mortars with 7% of cement replacement was performed to determine the pozzolanic activity of the waste nano-silica sludge. Finally, the hardened system was fully characterized to determine the phase composition. The results demonstrate that the nSS can be utilized as SCM to replace portion of cement in mortars, thereby decreasing the CO 2 footprint and the environmental impact of concrete.
K Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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an overview of the influences of mechanical and chemical processing on sugarcane bagasse ash characterisation as a Supplementary Cementitious Material
Journal of Cleaner Production, 2020Co-Authors: Ankur Laxman Yadav, V Sairam, L Muruganandam, K SrinivasanAbstract:Abstract Recent researchers are giving more importance to cut the practice of ordinary Portland cement (OPC) by replacing the Cementitious properties with industrial by-products in construction Materials as Supplementary Cementitious Materials (SCM). Many researchers are using Sugarcane Bagasse Ash (SCBA) as SCM which is an industrial by-product. Generally, SCM are pozzolanic Materials which are rich in alumina and silicate. Naturally these pozzolanic Materials may not be Cementitious, but had tendency to react with calcium hydroxide and water in order to form Cementitious compounds. The present paper reviews the processing adopted on sugarcane bagasse ash in order to transform it into Supplementary Cementitious Material. The procedure to develop the sugarcane bagasse ash as a pozzolanic Material is planned through a structure. The chemical compositions and physical properties of SCBA from the various sources are has been discussed. Furthermore, the influence of grinding and calcination on the characterisation of sugarcane bagasse ash has been discussed. Basically, the characterisation of sugarcane bagasse ash were studied on the basis of physical properties, chemical properties and microstructural studies. This review paper focuses on micro analytical studies of SCBA samples with respect to X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and Scanning electron microscope (SEM). The micro analytical investigation reveals that grinding made SCBA finer and calcination process had reduced the carbon the content in SCBA along with there is an increase in the amorphous reactivity as due to the increment in pozzolanic oxides, observed in X-ray fluorescence (XRF).
Blessen Skariah Thomas - One of the best experts on this subject based on the ideXlab platform.
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green concrete partially comprised of rice husk ash as a Supplementary Cementitious Material a comprehensive review
Renewable & Sustainable Energy Reviews, 2018Co-Authors: Blessen Skariah ThomasAbstract:Abstract The production of cement depletes natural resources, consumes high energy and emits huge amounts of green house gases. It accounts for almost 7% of the global carbon dioxide emissions, as the production of one ton of ordinary Portland cement releases approximately one ton of carbon dioxide. Due to the severe environmental pollution and health hazards associated with the cement and construction industries, they are under the strict scrutiny from the governments and environmentalists. Rice husk is an agricultural waste, whose natural degradation is restricted due to the irregular abrasive surface and high siliceous composition. It is not appropriate to be used as a feed for animals due to the low nutritional values. If dumped as landfill, they can take a lot of area and become a major challenge to the environment. If they are disposed by burning, the ashes can spread to the surrounding areas, create pollution and destroy the natural beauty. One of the possible solutions for the disposal of rice husk is to convert them into rice husk ash and incorporate them into cement based Materials. The partial inclusion of rice husk ash (RHA) for cement is found to be durable, environmental friendly and economically viable. This paper presents an overview of some of the published results on the successful utilization of rice husk ash as a Supplementary Cementitious Material and the properties of such concrete at fresh and hardened stages. Studies indicate that there is a promising future for the use of rice husk ash in normal, high strength and self compacting concrete as it shows high strength, low shrinkage and permeability, high resistance to carbonation, chloride, sulfate and acidic environments. The summery and discussions provided in this paper should provide new information and knowledge on the applications of greener and sustainable rice husk ash concrete.
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sustainable concrete containing palm oil fuel ash as a Supplementary Cementitious Material a review
Renewable & Sustainable Energy Reviews, 2017Co-Authors: Blessen Skariah Thomas, Sanjeev Kumar, Hasan Sahan ArelAbstract:Abstract Palm oil fuel ash (POFA) is a waste Material generated in power plants as a result of the combustion of palm oil industry waste for the generation of electricity. They are generally disposed to open fields causing traffic hazards besides potential of health hazards and environmental pollution problems. Due to its abundance and high pozzolanic characteristics, many researchers have evaluated its potential as a construction Material. This paper presents an overview of some of the published results on the successful utilization of palm oil fuel ash as a Supplementary Cementitious Material and the properties of such concrete at fresh and hardened stages. Studies indicate that there is a promising future for the use of POFA in normal, high strength and self compacting concrete as it shows high strength, low shrinkage and permeability, high resistance to carbonation, chloride, sulfate and acidic environments. At elevated temperature, the POFA concrete perform better than the ordinary Portland cement (OPC) concrete. The summery and discussions provided in this paper should provide new information and knowledge on the applications of greener and sustainable palm oil fuel ash concrete.
Ping Zhang - One of the best experts on this subject based on the ideXlab platform.
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characterization of sugarcane bagasse ash as a potential Supplementary Cementitious Material comparison with coal combustion fly ash
Journal of Cleaner Production, 2020Co-Authors: Ping Zhang, Wenyu Liao, Aditya Kumar, Qian ZhangAbstract:Abstract This study aims to evaluate the potential of sugarcane bagasse ash (SCBA) as a Supplementary Cementitious Material (SCM) in terms of composition. Using coal-combustion fly ash (CFA) as the benchmark, SCBA is characterized thoroughly using multiple tools to determine and compare particle size, particle morphology, chemical composition, glass content, element distribution and chemical status. It is found that SCBA has fine particle size (d50 = 6.76 μm, compared to 2.2 μm of CFA), high glass content (78.5 wt%, compared to 81 wt% of CFA), and relatively stable chemical composition, making it a potential effective SCM. The glass content of SCBA is dominated by amorphous silica (77.2%, compared to 53.6% of CFA), which can lead to formation of secondary calcium silicate hydrates in pozzolanic reactions. However, SCBA contains no spherical glass grains but many porous grains, which may compromise the workability of fresh-state cement-based Materials. Another two detriments of SCBA are high carbon and potassium contents, which could potentially interfere the performance of cement-based Materials. However, due to their existence forms (i.e., either light or dissolvable, as revealed by X-ray photoelectron spectroscopy), these detrimental effects can be mitigated through washing. A literature-survey based analysis shows that the ash samples adopted in this study are representative, so the conclusions drawn from this study are generally meaningful.
