HYDRATION OF PORTLAND CEMENT AND SURFACE AREA OF HARDENED CEMENT PASTE BY WATER VAPOR ADSORPTION MEASUREMENT

The specific surface area of 60 mineral soil samples estimated by water vapor adsorption at 20 % relative humidity ranged from 12.1 ± 3.6 to 225.1 ±18.4 m2/g. Clay (range 1—72 %) and organic carbon content (0.7—14.6 %) together explained 84 % of the variation in the surface area. The regression equation predicting the specific surface area of soil was surface area (m2/g) =2.69+ 1.23clay-% +8.69org.C-%.

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On effect of superplasticizers and mineral additives on shrinkage of hardened cement paste and concrete

MATEC Web of Conferences ◽

10.1051/matecconf/201819604018 ◽

2018 ◽

Vol 196 ◽

pp. 04018 ◽

Cited By ~ 10

Author(s):

Grigory Nesvetaev ◽

Yulia Koryanova ◽

Tatiana Zhilnikova

Keyword(s):

Portland Cement ◽

Cement Paste ◽

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Hardened Cement ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Hardened Cement Paste ◽

Mineral Additive ◽

Mineral Additives

A model describing the variation in autogenous shrinkage and drying shrinkage of portland cement concrete, depending on the volume of aggregates and the shrinkage of hardened cement paste, is presented. The equation to calculate shrinkage of concrete as a function of the volume of aggregates and shrinkage of a hardened cement paste was proposed. Formulas are proposed that describe the change in the shrinkage of hardened cement paste as a function of water/cement. The results of studies of the effect of superplasticizers and mineral additives on the autogenous shrinkage and the drying shrinkage of hardened cement paste are presented. Concretes made with superplasticizer and mineral additive may have the potential lower the value of drying shrinkage. The shrinkage value can be lowered from 30% till 70%. Concretes containing superplasticizers and mineral additives can potentially have the autogenous shrinkage reduced to 75%, or increased to 180%.

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Water Vapor Adsorption Capacity of Thermally Fluorinated Carbon Molecular Sieves for CO2Capture

Journal of Nanomaterials ◽

10.1155/2013/705107 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Jin-Young Jung ◽

Hye-Ryeon Yu ◽

Se Jin In ◽

Young Chul Choi ◽

Young-Seak Lee

Keyword(s):

Water Vapor ◽

Specific Surface ◽

Adsorption Capacity ◽

Surface Area ◽

Specific Surface Area ◽

Molecular Sieves ◽

Total Pore Volume ◽

Water Vapor Adsorption ◽

Carbon Molecular Sieves ◽

Vapor Adsorption

The surfaces of carbon molecular sieves (CMSs) were thermally fluorinated to adsorb water vapor. The fluorination of the CMSs was performed at various temperatures (100, 200, 300, and 400°C) to investigate the effects of the fluorine gas (F2) content on the surface properties. Fluorine-related functional groups formed were effectively generated on the surface of the CMSs via thermal fluorination process, and the total pore volume and specific surface area of the pores in the CMSs increased during the thermal fluorination process, especially those with diameters ≤ 8 Å. The water vapor adsorption capacity of the thermally fluorinated CMSs increased compared with the as-received CMSs, which is attributable to the increased specific surface area and to the semicovalent bonds of the C–F groups.

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