The effect of sucrose on the kinetics of cement hardening has been studied. The study was carried out in two comparative ways, one of which had the organic modifier introduced into cement as gauging liquid ("water-2% sucrose solution"), the other-as suspensions "cementwater-2% sucrose solution". The products of sucrose corrosion, synthesized in suspensions, were used as addition agents in the "cement-water" system. Suspension-based approach is interesting because of cement modification by introducing the corrosion products of the same cement, which provides setting acceleration and higher composite density.The structurization role of addition agents, containing products of sucrose corrosion of cement, is provided by synergetic influence of several factors: intensive growth of ettringite crystal nucleithe main reinforcement component of a cement system, reduction of Са(ОН)2 in solid phase of a rock, CSH-gel densifying and plasticizing. The use of sucrose as gauging liquid results in adverse effect for isolation of cement particles by adsorption layers, impeding the hydration, growth and possible coalescence of crystalthe destructurization of the setting system: the rocks, available from cement gauging with 2 % sucrose solution were not set during the whole trial period. The results were interpreted by means of physic-chemical approaches: X-ray phase analysis, IR-spectroscopy, differential thermal analysis.

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The paper deals with research data of reinforced concrete rectangular and I-shaped cross-section elements, operating under oblique eccentric short-term dynamic compression, tension and bending. The method of reinforced concrete elements calculation using the theory of surfaces of relative resistance regarding strength and crack resistance is suggested. It is based on the deformation model with the use of real nonlinear diagrams of concrete and reinforcement. This method makes it possible to observe strength and crack resistance of reinforced concrete elements sections in the entire range of loadings from the central tension to axial compression. Experimental investigation of symmetrically reinforced concrete elements on oblique eccentric short-term dynamic compression, tension and oblique bending was carried out. Effect of longitudinal force level on strain distribution through the depth of section, bearing capacity, the failure scheme and other parameters are estimated.

Abstract. The paper presents investigations of the mechanism of UO 2 2+ cation sorption by natural zeolites and peat from aqueous solutions using a limited volume method. It is proved that the sorption rate depends on sorbent granulating, dioxouran (VI) temperature and concentration. The results show that sorption of UO 2 2+cations by natural sorbents is the mixed-diffusional mechanism. The use of 24-hour interruption technique ('kinetic memory') demonstrates that in the mixed-diffusional mechanism for natural peat and zeolites the internal ion diffusion predominates. The coefficients of internal diffusion and activation energy are calculated in this paper. The infrared spectroscopy technique and synchronous thermal test are used to identify the interaction between dioxouran (VI) and energy components of natural sorbents. The synchronous thermal test shows that UO 2 2+ cation sorption decreases the thermal stability of peat as compared to its original state. The peat decomposition is determined after UO 2 2+ cation removal as well as the appearance of end-effect maximum of 777.5 0 C. An assumption is made on a possible decomposition of different metal oxalates in peat and clay peat bonds which irreversibly absorb UO 2 2+ cations. These research findings can be recommended for water purification at nuclear fuel cycle facility.

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