Applied Mechanics and Materials Vols. 725-726

Abstract: New theoretical justification for the function of soil differential moisture capacity (dependence of the relative water volume content on the capillary pressure) and its antiderivative is presented. New method is based on the concept of capillarity and the lognormal distribution of the effective radii of pores. Relative hydraulic conductivity of soil is calculated with usage of these functions and Mualem's approach. Hydrophysical parameters have been interpreted and evaluated on the base of some physical and statistical soil characteristics. Also the approximation for functions of water-retention capacity and relative hydraulic conductivity of soil has been proposed.

Abstract: Non-stationary inhomogeneous system of the Navier–Stokes equations with variable viscosity depending on the density has been used for modeling the process of the cohesive soil erosion. Value of the density has been determined by the convection–diffusion equation. For solving the obtained system we have used an algorithm consisting of the splitting scheme on physical factors and the predictor–corrector method. The system has been solved on the staggered grid by the grid method. The results of calculations for two-dimensional and three-dimensional problems are presented.

Abstract: We propose a new algorithm for counting closed pores in porous materials. Closed pore can be defined as isolated object of arbitrary shapes in rectangular domains or binary images. The algorithm is based on two cellular automata (CA). First CA saves 2 or more connectivity of image while the second CA is Leviald’s CA that count 1-connected parts after transformations of the initial image. The CA algorithm was implemented on a parallel computer. Computational performances are evaluated and measured on real cases. The obtained results indicate that the proposed approach achieves comparable complexity as standard approaches; however, the number of processing nodes does not limit the speedup and scalability of the proposed algorithm.

Abstract: The influence of additives on the radiation stability of the concrete will occur through the influence of radiation changes of hardened cement paste on radiation changes of concrete and can be quite significant. The test sequence was produced according to the modified method described in case [11]. The samples were prepared in the form of prisms with the following dimensions: 10 mm x 10 mm, 30 mm. Measurement series were produced after each heating and cooling sequence. Then the difference between the values before and after heating was calculated.

Abstract: In the conditions of the modern industry, manufacturing the main materials and products is more estimated in the parameters characterizing the quantity of the formed waste. A progressive tendency in material-intensive branches is transformation of industrial wastes into the raw materials suitable for industrial use. It refers completely to the ashes of thermal power stations (TPS) and state district power stations (SDPS).

Abstract: The concretes and mortars based on the Portland cement are able to perform the functions of the protective and durable materials for the disposal and long term storage of radioactive waste. It has investigated the influence of fineness of the carbon-containing component and the type of the water-reducing polycarboxylate-based admixtures on the properties of protective concrete of the recommended optimal composition.

Abstract: The article presents the possibilities for the contemporary application of Styrofoam in the elements of building structures. Having in mind that Styrofoam belongs to a group of highly flammable materials, 5 % of combustion retarder - so called "retardant" - needs to be added to the amount when produced for structural building elements. That kind of Styrofoam is called "self-extinguishing" contrary to "normal" that does not contain that substance. The Article also shows the way in which building elements are constructed (external and interfloor construction), made out of Styrofoam using "Plastbau" technology. A possibility to use exterior wall panels ‘Plastbau’ under weather conditions of Saint-Petersburg has been considered. Temperature distribution along a wall’s section as well as a heat flow going through a building enclosure ‘Plastbau’ have been also analyzed herein.

Abstract: The article describes the results of an experiment, that was conducted in the Biological Institute laboratory of Staint-Petersburg State University in Peterhof. The purpose of the experiment was to study the destruction processes of lime plaster and lime masonry mortar samples under the action of different organic acids, which are metabolic products of fungi.

Abstract: This paper will present testing of masonry walls made from clay block and concrete block. Experimental testing of the walls is done in the laboratory of the University of Civil Engineering in Podgorica within the national scientific research project "Seismic risk reduction in buildings of stone and brick". This paper presents the results of testing samples of walls built with the tested masonry elements and mortar. Characteristic compressive strength of the walls and elasticity modules were obtained. An analytical approach to determining the characteristic compressive strength and elasticity modules of masonry walls is analyzed in accordance with the applicable standard of Yugoslavia PIOVS'91, European standards EN 1996-1-1: 2005 and the American standard ACI 530.

Abstract: Investigated coeffect of superplasticizer S-3 and air-entraining agents LHD (wood chemical additive) on workability, cohesion and air entrainment of concrete mix. Found that under introducing an additive LHD into the concrete mix comprising supeplastifikator S-3, the mobility of the concrete mix is reduced despite the fact that the additive LHD itself is a plasticizer. Decreased mobility from the introduction 0.1 % LHD makes: slump Abrams - 5-6 %, slump flow - 18-22 %. At the same time LHD additive contributes significantly air entrainment and reduce separating water and mortar. Effect of increasing the connectivity of the concrete mix associated with air entrainment. Regardless of the LHD additive S-3 additive does not reduces water separating, and does not have air-entraining action, and virtually no effect on air entrainment caused by the addition of LHD. With increasing content in the concrete mix additives LHD regardless of dosage S-3 amount of entrained air increases from 3 to 7%, and water separation is reduced to almost 0. Thus, synergy additives S-3 and LHD against plasticize the concrete mix was negative, but a positive effect has been observed in respect of connectivity concrete mix.