The Use of Thermogravimetric Analysis to Characterize the Metallic Slag Aggregates in Structural Concrete

2020 ◽  
Vol 1012 ◽  
pp. 272-277
Author(s):  
Tiziana Azario de Medeiros ◽  
Eliane Kujat Fischer ◽  
Rafael Aparecido Ciola Amoresi ◽  
Maria Aparecida Zaghete ◽  
Jusinei Meireles Stropa ◽  
...  
Keyword(s):  
Portland Cement ◽  
Morphological Changes ◽  
Nitrogen Adsorption ◽  
Concrete Sample ◽  
Chemical Characteristics ◽  
Structural Concrete ◽  
Metallic Component ◽  
Additional Resistance ◽  
Nitrogen Adsorption Isotherms ◽  
Mineralogical Compositions

Structural concretes must have a set of chemical characteristics to present a satisfactory resistance to the degradation in environment conditions. Besides the several types of mineralogical compositions, the calcium-rich sulfates, silicates and aluminates phases appear as majority components, but the gypsum one seems to play the most important rule in morphological changes during the concrete cure. In this work, it was carried out several characterizations in commercial Portland cement and the structural concrete sample. Nitrogen adsorption isotherms at 77 K for Portland cement showed the thermal treatment at 500 oC does not undergo significant decreasing in surface area due the high content of porous silicates and aluminates components. The additional resistance to the corrosion of structural concretes exposed at environment conditions can be associated to presence of slag metallic aggregates, which could be characterized successfully by thermal analysis. The amount of embedded metallic component in concrete sample was detected by typical weight gain originated form oxygen incorporation above 700 oC.

Chemical, Physical and Engineering Characterization Of Candidate Backfill Clays and Clay Admixtures for a Nuclear Waste Respository-Part I

1981 ◽  
Vol 6 ◽  
Author(s):  
Sudesh K. Singh
Keyword(s):  
Nuclear Waste ◽  
Morphological Changes ◽  
Deionized Water ◽  
Engineering Properties ◽  
Nuclear Waste Repository ◽  
Exchange Cation ◽  
Mineral Components ◽  
Waste Repository ◽  
Mineralogical Compositions

ABSTRACTFourteen Canadian clays and clay admixtures were subjected to simulated nuclear waste repository environments. The present work is concerned with the montmorillonite-dominant materials only. The montmorillonite-dominant samples showed significant leaching on interaction with deionized water. On heating the samples at 200°C for 500 hours, montmorillomites lost intermicellar water completely and acquired cusp-like to cylindrical morphologies. The loss of water and the morphological changes in montmorillonites significantly altered the engineering characteristics. Permeability, shrinkage limits, compactability and shear strength varied in response to the dominant exchange cation in the structure of montmorillonites and the presence of other mineral components in the materials. The synthetic granite water reacted with montmorillonites and led to changes in chemical and mineralogical compositions, crystalline state and engineering properties.

PERMEABILITY STUDIES: III. SURFACE AREA MEASUREMENTS OF CARBON BLACKS

1948 ◽  
Vol 26a (2) ◽  
pp. 29-38 ◽  
Author(s):  
J. C. Arnell ◽  
G. O. Henneberry
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Carbon Black ◽  
Surface Area ◽  
Satisfactory Agreement ◽  
Nitrogen Adsorption ◽  
Average Particle ◽  
Carbon Blacks ◽  
Permeability Studies ◽  
Nitrogen Adsorption Isotherms

The modified Kozeny equation has been found to be satisfactory for the measurement of the specific surfaces of carbon blacks having average particle diameters ranging from 0.01 to 0.1 μ to within ±10%. Comparative data were obtained from electron microscope counting and from low temperature nitrogen adsorption isotherms. The three methods examined gave results that were in satisfactory agreement, except when the carbon black was porous, and then the adsorption value was extremely large.

Characterisation of the Filter Elements of End-of-Life Biological and Chemical Protection Masks Used by the Army

2008 ◽  
Vol 587-588 ◽  
pp. 778-782
Author(s):  
Marta Cabral ◽  
João C. Bordado ◽  
António Correia Diogo ◽  
Fernanda Margarido
Keyword(s):  
End Of Life ◽  
Nitrogen Adsorption ◽  
Added Value ◽  
Carbon Cloth ◽  
Activated Carbon Cloth ◽  
Chemical Protection ◽  
Physico Chemical ◽  
Nitrogen Adsorption Isotherms ◽  
Dissolved Components

The main purpose of the present study is to assess the usefulness of filter cartridges from end-of-life biological and chemical protection masks, for other applications (with increased added value) instead of landfill deposition. Filters with different ages up to fifty years, were dismantled and divided in their components. Physico-chemical characterisation of each filter cartridge component was performed using different techniques such as: optical microscopy, Fourier transform infrared spectroscopy, pyrolysis, particle size distribution by laser diffraction, surface area determination from the nitrogen adsorption isotherms at 77K, determination of open porosity by helium pycnometry, and dynamic mechanical thermal analysis in the temperature range from -100°C to 200°C. It is shown that the loss of resilience of the rubber sealant is the main factor that controls the shelf life of filter cartridges. On the other hand, most of the charcoal in the activated carbon cloth remains active and can be useful for other less severe applications such as the removal of dissolved components from freshwater and/or marine systems.

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