Novel cement matrices by accelerated hydration of the ferrite phase in portland cement via chemical activation: kinetics and cementitious properties

1995 ◽  
Vol 2 (5) ◽  
pp. 189-200 ◽  
Author(s):  
Wolfgang Schwarz
Keyword(s):  
Portland Cement ◽  
Chemical Activation ◽  
Ferrite Phase ◽  
Activation Kinetics ◽  
Cement Matrices

Chemical activation of hybrid binders based on siliceous fly ash and Portland cement

2016 ◽  
Vol 66 ◽  
pp. 10-23 ◽  
Author(s):  
Salaheddine Alahrache ◽  
Frank Winnefeld ◽  
Jean-Baptiste Champenois ◽  
Frank Hesselbarth ◽  
Barbara Lothenbach
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Chemical Activation

Impact of Grinding Technology on Final Properties of Portland Cement

2016 ◽  
Vol 677 ◽  
pp. 191-196
Author(s):  
Karel Dvořák ◽  
Dusan Dolak ◽  
Iveta Hájková
Keyword(s):  
Portland Cement ◽  
Raw Materials ◽  
Chemical Activation ◽  
Technical Equipment ◽  
Production Methods ◽  
The Past ◽  
Main Emphasis ◽  
Save Energy ◽  
Burning Mode ◽  
Reducing Energy

Portland cement got his name derived from the appearance of concrete that resembles sandstone located near city of Portland in England. In 1824, John Aspdin was granted a patent for the production of Portland cement.In the past, energy and economic demands on production of cement were lower than they are today. Production was characterized by a slower burning mode and coarser grinding. Product produced this way were reaching lower compressive strength.Currently there are several companies producing Portland cement. Main ones in Czech Republic are Holcim, Heidelbergcement group and Lafarge Cement a.s. Their production methods are very similar. The differences are mostly in the possibility of using local raw materials with different chemical composition and the technical equipment of factories. In the production, the main emphasis is on reducing energy and financial cost.One way to save energy and money is to use mechanical-chemical activation when grinding Portland clinker.

Chemical Activation of Cementing Properties of Granulated Blast Furnace Slags

2012 ◽  
Vol 454 ◽  
pp. 11-16
Author(s):  
Xian Jun Lu ◽  
Shu Gang Hu ◽  
Zi Qiao Jin
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Amorphous Materials ◽  
Chemical Activation ◽  
Xrd Analysis ◽  
Hydration Products ◽  
X Ray ◽  
Early Strength ◽  
Activated Slag ◽  
Alkali Activated

Using CaO, NaOH and Na2CO3 as activators, the effects of dosage and combination of the activators on the cementing property of granulated blast furnace slags were investigated, and the hydration products of the activated slags were detected by X-ray powder diffraction (XRD) analysis. Results indicate that CaO can be used as an effective activator for the slag samples and its optimum dosage is about 10%, but the CaO activated slags shows much lower early strength than the Portland cement. However, the early strength of the CaO activated slag can be remarkably improved by the addition of NaOH or Na2CO3. Under the addition of about 6% NaOH or Na2CO3, the overall compressive strength of the alkali activated slag is higher than a 42.5MPa Portland cement. XRD analysis revealed that the hydration products of the alkali activated slags are mainly amorphous materials, which is quite different from that of the Portland cement.

A cleaner material production by the incorporation of the rockwool waste into portland cement matrices

2021 ◽  
Vol 293 ◽  
pp. 126059
Author(s):  
Maiara Goulart Medeiros ◽  
Willian Cézar Nadaleti ◽  
Janaide Cavalcante Rocha ◽  
Malik Cheriaf ◽  
Philippe Jean Paul Gleise ◽  
...  
Keyword(s):  
Portland Cement ◽  
Material Production ◽  
Cement Matrices

scholarly journals Structure and properties of fine concretes based on composite binders

Vestnik MGSU ◽  
2019 ◽  
pp. 322-331 ◽  
Author(s):  
Aleksey I. Kharchenko ◽  
Vyacheslav A. Alekseev ◽  
Igor’ Ya. Kharchenko ◽  
Dmitriy A. Bazhenov
Keyword(s):  
Moisture Content ◽  
Portland Cement ◽  
Porous Structure ◽  
Crack Resistance ◽  
Chemical Activation ◽  
Silica Sand ◽  
Structure And Properties ◽  
Strength Performance ◽  
Technical Properties ◽  
Performance Results

Introduction. Wide introduction of fine concretes in the practice of monolithic building construction is limited by their low crack resistance due to considerable shrinkage. To reduce the shrinkage adverse effect on structure and properties of the fine concretes, it is suggested to use for their preparation composite binders, including expanding sulphoaluminate-based cements. Using the fine concrete with enhanced physical and technical properties improves produceability of construction, reduces labor input of concrete casting and allows building installations of complicated architectural forms. Material and methods. To study processes of fine concrete structure formation and properties, concrete mixes were prepared on the base of medium silica sand, dispersed ash entrainment and expanding additive. Activity of the ash entrainment increased at the expense of mechanical and chemical activation. Dispersity of the particles was monitored by means of laser granulometry. The composite binder was prepared by means of thorough homogenization of the basic CEM 42.5 Portland cement and different sorts of mineral aggregates, including an expanding additive based on calcium sulphoaluminate. Maturing conditions at a certain moisture content were simulated for every composition with subsequent evaluation of concrete performance. Results. Results of the study include effect of different mineral additives distinguishing in mineral composition, dispersivity and degree of hydraulic activity on shrinkage amount and kinetics, fine concrete porous structure parameters and strength. It is understood that amount of expansion has an effect on porous structure characteristics of the fine concrete and its strength performance. The study assessed an influence of maturing conditions on the various-composition fine concrete. A considerable influence of maintaining optimal moisture content during hydration on fine concrete technical properties is committed. Conclusions. It is understood that introduction of up to 10 % of expanding sulphoaluminate-based component in basic Portland cement allows to obtain fine concrete with enhanced crack resistance, impenetrability and longevity.

scholarly journals Effect of Pyrogenic Silica and Nanosilica on Portland Cement Matrices

2018 ◽  
Vol 30 (10) ◽  
pp. 04018266 ◽  
Author(s):  
Jorge I. Tobón ◽  
Oscar Mendoza Reales ◽  
Oscar Jaime Restrepo ◽  
María Victoria Borrachero ◽  
Jordi Payá
Keyword(s):  
Portland Cement ◽  
Pyrogenic Silica ◽  
Cement Matrices

scholarly journals Intensification of loosening of asbestos fibers by means of hydromechanical processing

2021 ◽  
pp. 26-29
Author(s):  
O.M. Obodovich ◽  
O.M. Nedbailo ◽  
O.G. Chernyshyn ◽  
A.E. Nedbailo
Keyword(s):  
Portland Cement ◽  
Cement Mortar ◽  
Chemical Activation ◽  
Asbestos Fibers ◽  
Physico Chemical ◽  
Asbestos Cement ◽  
Ventilation Ducts ◽  
Building Surfaces ◽  
Reduced Costs ◽  
High Degree

Acceptance of high-quality aqueous suspensions based on chrysotile asbestos is an urgent technical task in a number of industries. Asbestos-cement mortar is used as an asbestos-cement crust for insulation of walls and other building surfaces, due to this composition of the treated surfaces perfectly retain heat, resistant to moisture, and most importantly - asbestos fibers contribute to the smoothness of the surface and crack is not formed. No less popular is the use of asbestos-cement mortar with a high content of asbestos in the insulation of ventilation ducts and pipelines. This composition of asbestos-cement mortar is used to strengthen the joints of asbestos-cement pipes, as well as as a filler in the laying of cast iron pipes to give the joints additional elasticity. Asbestos-cement mortar has plasticity, resistance to stretching and reinforcement of asbestos, as well as strength and versatility in the use of cement. Due to these properties, asbestos and cement perfectly adhere to each other to obtain a durable, strong, frost-resistant, virtually waterproof and fire-resistant building material. The result of the microscopic examination is reason to believe that from the technological process of production of slate can be removed electromechanical mixer for the preparation of a solution of asbestos + water + portland cement. In this case, given the fact of continued loosening of asbestos in the preparation of the mold mixture of asbestos + water + portland cement, it will be sufficient to ensure the degree of loosening of asbestos in the ripper at the minimum required level (for example, not more than 85%). It is assumed to obtain a mold mixture with a high degree of homogeneity of the components with reduced costs of Portland cement due to its physico-chemical activation by hydraulic fluxes.

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