scholarly journals Influence of supplementary cementitious materials on hydration and microstructure development of concrete

2019 ◽  
Vol 1 (1) ◽  
pp. 43-44
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Cement Clinker ◽  
Hydration Kinetics ◽  
Supplementary Cementitious Material ◽  
Industrial Manufacturing ◽  
Portland Cement Clinker ◽  
By Products

Several supplementary cementitious materials (SCM) were blended with Portland cement clinker in order to produce more sustainable binders. The use of such materials, where no additional clinkering process is involved, leads to a significant reduction in CO2 emissions per ton of cementitious materials (grinding, mixing and transport of concrete and use very little energy compared to the clinkering process) and is a means to (re)utilize by-products of industrial manufacturing processes. Fly ash, for example, is the most commonly used supplementary cementitious material. The blending of Portland cement with fly ash results in the reduction of the total amount of portlandite in the hydrated mixture [1-4], somewhat less pronounced than for silica fume as: the reactivity of fly ash is very limited and as the CaO in the fly ash is an additional source of calcium [5]. Since fly ash particles are more spherical in shape than cement particles, workability and pumpability can be improved, by adding fly ash, also, fly ashes can cause low early strengthening. In this paper, the effects of Fly-ash as SCM’s on microstructure and hydration kinetics are studied.

scholarly journals Synthesis and Characterization of a Hybrid Cement Based on Fly Ash, Metakaolin and Portland Cement Clinker

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1084 ◽  
Author(s):  
Adriagni C. Barboza-Chavez ◽  
Lauren Y. Gómez-Zamorano ◽  
Jorge L. Acevedo-Dávila
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cementitious Materials ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Cement Clinker ◽  
Dense Matrix ◽  
X Ray ◽  
Reduction Of Co2

Hybrid cement has become one of the most viable options in the reduction of CO2 emissions to the environment that are generated by the cement industry. This could be explained by the reduction of the content of clinker in the final mixture and substitution of the remaining percentage with supplementary cementitious materials with the help of an alkaline activation. Following that, properties that are provided by an Ordinary Portland Cement and of a geopolymer are mixed in this type of hybrid material and could be achieved at room temperature. Thereafter, the main objective of this research was to synthesize hybrid cements reducing the clinker content of Portland Cement up to 20% and use metakaolin and fly ash as supplementary cementitious materials in different proportions. The mixtures were alkaline activated with a mixture of sodium silicate and sodium hydroxide, calculating the amounts according to the percentage of Na2O that is present in each of the activators. The samples were then characterized using Compressive strength, X-ray diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy with energy-dispersive X-ray spectroscopy. The results indicated that the hybrid cements have similar mechanical properties than an Ordinary Portland Cement, and they resulted in a dense matrix of hydration products similar to those that are generated by cements and geopolymers.

Microstructure of Cement Blends Including Fly Ash, Silica Fume, Slag and Fillers

1986 ◽  
Vol 86 ◽  
Author(s):  
Micheline Regourd
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Silica Fume ◽  
Blended Cement ◽  
Cement Clinker ◽  
Microstructural Development ◽  
Limestone Filler ◽  
Portland Cement Clinker

ABSTRACTThe hydration of a blended cement through hydraulic or pozzolanic reactions results in heterogeneous polyphase materials. Because portland cement clinker is the major component in most cement blends, the microstructural development of portland cement hydrates, including C-S-H and pore structures, is first discussed. Slag, fly ash, silica fume and limestone filler cements are then compared to portland cement with regards to C-S-H morphology and composition, aluminate crystallization, cement paste interfaces and pore size distribution.

NTCC 2017: Long-Term Observation of the Resistance of Novel Hybrid Cement Exposed to Sulphate Solution

2018 ◽  
Vol 761 ◽  
pp. 163-168 ◽  
Author(s):  
Michal Bačuvčík ◽  
Pavel Martauz ◽  
Ivan Janotka
Keyword(s):  
Portland Cement ◽  
Building Materials ◽  
Sodium Sulphate ◽  
Sulphate Solution ◽  
Cement Clinker ◽  
Portland Cement Clinker ◽  
Specific Material ◽  
Long Term Observation ◽  
By Products

This work is aimed to investigate four-years impact of 5 % sodium sulphate solution on the mortar made of novel hybrid cement H-CEMENT, being prepared with maximal content of wastes and by-products and only 20 % wt. of Portland cement clinker, compared to that prepared with the reference CEM I 42.5 N (PC). H-CEMENT for its specific material composition does not meet the criteria for inclusion in the cement kinds reported in EN 197-1 but complies with all of the hygienic regulations and standards imposed on similar building materials.

Quantification of supplementary cementitious content in blended Portland cement using an iterative Rietveld–PONKCS technique

2017 ◽  
Vol 50 (2) ◽  
pp. 498-507 ◽  
Author(s):  
Yuri P. Stetsko ◽  
Natallia Shanahan ◽  
Harvey Deford ◽  
A. Zayed
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Binary Systems ◽  
Accurate Determination ◽  
Ternary Systems ◽  
Cementitious Materials ◽  
Iterative Refinement ◽  
Supplementary Cementitious Materials ◽  
Amorphous Content ◽  
Wide Range

An iterative Rietveld–PONKCS (partial or no known crystal structure) technique has been developed for precise and accurate determination of the weight percentages of predominantly amorphous supplementary cementitious materials (SCMs) contained in Portland cement–SCM blends. This technique involves the iterative refinement of the SCM amorphous phase (SCMAP) content, with the separation of the refinement of the SCMAP shape parameters from background refinement. The technique also includes an internal and external standard refinement of both the calibration SCM and the cement–SCM blend. This approach enables the separation of the contributions of the SCMs and the cement to the amorphous content of the cement–SCM blend. The technique has been successfully applied to binary systems of cement–slag and cement–fly ash, and ternary blends of cement–fly ash–slag, over a wide range of cement replacement levels. In the ternary systems, the proposed technique was successfully able to separate the individual amorphous contributions of slag and fly ash to the total amorphous content of the system. The approach was also implemented on a pair of commercially available binary blended cements containing 30% slag and 30% fly ash, respectively.

Tentative Optimum Proportion of Supplementary Cementitious Materials in Blended Cement to Perform Better under Tannery Wastewater

2018 ◽  
Vol 937 ◽  
pp. 107-113
Author(s):  
Samina Samrose ◽  
Saifa Anzum ◽  
Samira Mahmud ◽  
Tanvir Manzur
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Blended Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Effluent Treatment ◽  
Tannery Wastewater ◽  
Wastewater Sample ◽  
Supplementary Cementitious Material ◽  
Optimum Proportion

The present research studies the compressive strength of cement mortar cubes prepared from different proportions of supplementary cementitious materials (Fly Ash and Slag) in blended cement. This research aims to find the tentative optimum composition of supplementary cementitious material that shows better performance under tannery wastewater condition, such as that in effluent treatment plants. Synthetic tannery wastewater was simulated in laboratory after collecting wastewater sample from local tannery industry. Eight types of cement compositions (varying supplementary materials proportions) have been chosen. Compressive strength test has been conducted on mortar cubes over a period of three months. Test results revealed that slag addition had shown significantly stronger effects than that of fly ash addition. Also, the combined effect of fly ash and slag and their order of variation on strength were studied. The observations made from this research will be helpful for selection of blended cement proportions in future structures exposed to similar severe conditions.

scholarly journals Influence of Steel Slag Type on Concrete Shrinkage

2020 ◽  
Vol 13 (1) ◽  
pp. 214
Author(s):  
Maria Dolores Rubio-Cintas ◽  
Maria Eugenia Parron-Rubio ◽  
Francisca Perez-Garcia ◽  
António Bettencourt Ribeiro ◽  
Miguel José Oliveira
Keyword(s):  
Steel Slag ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Cement Clinker ◽  
Concrete Shrinkage ◽  
Granulated Blast Furnace Slag ◽  
Hydraulic Binder ◽  
Portland Cement Clinker ◽  
Different Characteristics ◽  
Furnace Slag

Building construction and building operations have a massive direct and indirect effect on the environment. Cement-based materials will remain essential to supply the growth of our built environment. Without preventive measures, this necessary demand in cement production will imply a substantial increase in CO2 generation. Reductions in global CO2 emissions due to cement consumption may be achieved by improvements on two main areas: increased use of low CO2 supplementary cementitious materials and a more efficient use of Portland cement clinker in mortars and concretes. The use of ground granulated blast furnace slag in concrete, as cement constituent or as latent hydraulic binder, is a current practice, but information of concrete with ladle furnace slag is more limited. Specific knowledge of the behavior of mixtures with steel slag in relation to certain properties needs to be improved. This paper presents the results of the shrinkage (total and autogenous) of five concrete mixtures, produced with different percentages of two different slags in substitution of cement. The results show that shrinkage of concrete with the two different slags diverges. These different characteristics of the two materials suggest that their use in combination can be useful in optimizing the performance of concrete.

scholarly journals Feasibility of Using Biomass Fly Ash in Cementitious Materials

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 12
Author(s):  
Jonathan Page ◽  
Laurent Libessart ◽  
Chafika Djelal ◽  
Maurice Gonon ◽  
Issam Laiymani
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Water Demand ◽  
Isothermal Calorimetry ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Wood Biomass ◽  
Fly Ashes ◽  
X Ray ◽  
Biomass Fly Ash

In recent years, numerous studies focused on the development of sustainable cement-based binders through the use of supplementary cementitious materials such slag, fly ash, metakaolin, silica fume, pozzolan, etc. The use of wood biomass for power generation is increasingly common which lead to an important amount of waste produced in the combustion process such as fly ash, which must be transported to landfills for deposition, or used as sludge in farming. Depending on their chemical and physical characteristics, wood biomass fly ashes could be reuse in blended cements as supplementary cementitious material. Different sources of biomass fly ashes have been selected to evaluate their potential for use as a cement replacement. Their chemical and mineralogical compositions, as well as their morphology were first evaluated via X-ray and laser diffraction (XRD), inductively coupled plasma (ICP) and scanning electron microscopy (SEM coupled with energy-dispersive X-ray spectroscopy (EDX). Fly ashes showed variable physicochemical characteristics but some present interesting compositions for the intended use. One fly ash present a high content of CaO and minors of SiO2 and Al2O3. The chemical composition does not allow to categorize this fly ash as a pozzolan material but it may have a latent hydraulic behaviour, which could be interesting as cement substitution. This fly ash has been incorporated into a cement paste by progressive replacement of Portland cement (from 0 to 70%). It has been observed that biomass fly ash has a higher water demand compared to Portland cement. This additional water demand was evaluated by the Vicat consistency test and by an evaporometry method. The setting time and kinetic hydration of the biomass fly ash pastes were also assessed with the standardized Vicat test and by isothermal calorimetry.

scholarly journals Substitution of the clayey mineral component by lignite fly ash in portland cement clinker synthesis

2006 ◽  
Vol 60 (9-10) ◽  
pp. 253-258 ◽  
Author(s):  
Natasa Jovanovic ◽  
Miroslav Komljenovic ◽  
Ljiljana Petrasinovic-Stojkanovic ◽  
Zvezdana Bascarevic ◽  
Violeta Bradic ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Power Plants ◽  
Cement Clinker ◽  
Cement Factory ◽  
Lignite Fly Ash ◽  
Nikola Tesla ◽  
Portland Cement Clinker ◽  
Clayey Mineral ◽  
Limestone Sand

Fly ash from four power plants in Serbia (PP "Morava" - Svilajnac, PP "Kolubara" - Veliki Grijani, PP "Kostolac" - units B1 and B2 - Kostolac and PP "Nikola Tesla" - units A and B - Obrenovac) was utilized as the starting raw component for Portland cement clinker synthesis. Limestone and quartz sand from the "Holcim - Serbia, a.d." cement factory were the other two starting raw components. Based on the chemical composition of the raw components and from the projected cement moduli, the amounts of raw components in the raw mixtures were calculated. Six different raw mixtures were prepared - each one consisted of limestone, sand and different fly ash. A raw mixture from the industrial production of the "Holcim - Serbia, a.d." cement factory was used as the reference material. The prepared raw mixtures were sintered in a laboratory furnace at 1400?C. The chemical and mineralogical compositions of the synthesized clinkers were determined. The characteristics of clinkers, based on fly ash, were compared to the characteristics of the industrial Portland cement clinker from the "Holcim - Serbia, a.d." cement factory. The results of the investigation showed that fly ash from power plants in Serbia can be suitable for Portland cement clinker synthesis.

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