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Abstract: In soil mechanics the Atterberg limits are the most distinctive and the easiest property of fine-grained soils to measure. As they depend on the same physical factors as the other mechanical properties of soils, the values of the liquid and plastic limits would be a very convenient basis for their prediction. There are many studies concerning the use of the Atterberg limits in soil mechanics; however, their results vary considerably and are not generally applicable. This paper explains the main reasons for the different conclusions in these studies, which do not take into account the following: a) the water in fine-grained soils appears as interparticle and interaggregate pore water as well as adsorbed water onto the surfaces of clay minerals; b) the physical properties of fine-grained soils depend on the quantity of pore water only, because the adsorbed water is tightly tied on the clayʼs external and internal surfaces and thus cannot influence to them; c) the quantity of adsorbed water on the external surfaces of the clay minerals in soils depends mostly on the size and the quantity of the clay minerals, while the interlayer water quantity depends mostly on the quantity and the type of the swelling clay minerals in the soil composition and their exchangeable cations. From this it follows that for swelling and non-swelling soils, the uniform relationships between the Atterberg limits (which represent the total quantity of pore water and the adsorbed water onto the external and internal surfaces of clay minerals) and other physical properties does not exist. This paper presents some possibilities for the use of the Atterberg limits in predicting the soilʼs other properties for non-swelling and limited-swelling soils.
Keywords: Atterberg limits, specific surface area, undrained shear strength, compressibility, hydraulic conductivity
Published in DKUM: 14.06.2018; Views: 1401; Downloads: 95
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Abstract: Densities of ethanol-water mixtures have been measured using a vibrating tube densimeter and a different arrangement high-pressure experimental set-up. Measurements were carried out at 298,15 K in a pressure range from 0.1 MPa to 5MPa. Partial molar volumes, excess molar volumes and coefficients of isothermal compressibility were calculated. The molar volumes of alcohol and its partial molar volumes in mixtures with water are found to decrease monotonously with increasing pressure. Excess molar volumes are negative at all pressures. The numerical P-V relations at each composition are correlated satisfactorily as a function of pressure by the Hayward equation.
Keywords: chemistry, high-pressure vibrating tube densimeter, excess molar values, isothermal compressibility
Published in DKUM: 10.07.2015; Views: 1507; Downloads: 109
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Abstract: The densities of coenzyme Q10 in supercritical carbon dioxide were measured at 308.15, 313.15, 323.15 and 333.15 K and in the pressure range from 10 to 40 MPa with the vibrating tube densimeter. The reliability of the technique has been verified in our previous works and in the present work it was checked comparing our experimental densities of pure carbon dioxide with literature data. The partial molar volumes, isothermal compressibilities, isobaric thermal expansivities, internal pressures and cluster sizes were calculated from obtained densities.
Keywords: koenzim Q10, density measurements, partial molar volume, isothermal compressibility, isobaric thermal expansivity, internal pressure, supercritical carbon dioxide
Published in DKUM: 01.06.2012; Views: 1927; Downloads: 146
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Abstract: This article analyses the impact of soils` mineral composition on their compressibility. Physical and chemical properties of minerals which influence the quantity of intergrain water in soils and, consequently, the compressibility of soils are established by considering the previous theoretical findings. Test results obtained on artificially prepared samples are used to determine the analytical relationship between the water content and stress state, depending on the mineralogical properties of the soils. A practical applicability of the established interdependence is verified on fiverandomly selected samples of natural soils. The selected approach to the analysis of the influence of soils composition on the water content at different stress states allows for the first time to establish generally validcriteria for determining such relationship.
Keywords: soil mechanics, clays, specific surface, compressibility, mineral composition
Published in DKUM: 30.05.2012; Views: 1869; Downloads: 149
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