75504 2712-8172 3 38 2013 1-80

RAR RUS 7-14 Belgorod State Technological University named after V.G. Shukhov Klyuev Sergey Klyuyev@yandex.ru Belgorod State Technological University named after V.G. Shukhov Klyuev Alexander Klyuyev@yandex.ru

Belgorod, Russia

Belgorod State Technological University named after V.G. Shukhov Sopin D. Belgorod State Technological University named after V.G. Shukhov Netrebenko A. Belgorod State Technological University named after V.G. Shukhov Kazlitin S. Heavy loaded floors based on fine-grained fiber concrete Urgent problems of using needle fiber for fine-grained concrete disperse reinforcement are considered in the article. The fine cement and binder agent with low water requirements were used as an astringent. The main filling material of a fiber concrete mix was granite siftings. It is established that application of the composite binder agent and high-density packaging of filling grains increases strength properties a lot. Optimal selection of filling material allowed to receive steel fiber concrete with ultimate compressive strength 118,8 MPa, and ultimate bending strength 14,1 MPa for heavily loaded floors of industrial buildings. It is established, that application of composite binder agent and high-density packaging of filling grains of concrete matrix can be effective in social, ecological and economic spheres. Incidentally, the economic effect of using new building materials will consist in consumption decrease of astringent for account of optimal conditions of steel fiber concrete structure formation. 10.5862/MCE.38.1 fine-grained concrete technogenic sand fiber concrete https://engstroy.spbstu.ru/article/2013.38.1/ 01.pdf

RAR RUS 15-23 Voronezh State University of Architecture and Civil Engineering Shmitko E. Voronezh State University of Architecture and Civil Engineering Rezanov A. Voronezh State University of Architecture and Civil Engineering Bedarev A. bedarev@ogent.net Multiparameter structure optimization of the cellular silicate concrete Strengthening the concept of energy efficiency requires the development and implementation of high-performance wall materials. The most promising in this respect is the cellular silicate concrete (gas silicate), which properties are superior to other insulating building materials. However, production of gas silicate insulation purpose with medium density less than 300 kg/m3 poses a number of difficulties due to the nature of its structure. In this regard, the current task is to maintain the specified quality of concrete porous silica with a decrease in its average density. In the article this problem is solved by a multi-level optimization of the macro- and microstructure based on multi-rich (multiparameter) mathematical model. Algorithm and the general structure of the model and the results of laboratory studies are given. 10.5862/MCE.38.2 gas silicate cellular concrete multi-rich model structure optimization https://engstroy.spbstu.ru/article/2013.38.2/ 02.pdf

RAR RUS 24-28 Moscow State University of Civil Engineering Sandulyak Anna a.sandulyak@mail.ru Moscow State University of Civil Engineering Ershov D. Moscow State University of Civil Engineering Ershova V. Moscow State University of Civil Engineering Sandulyak A. Characteristics of the magnetic control of separable ferrous impurities contained in raw construction materials Currency of using the method of magnetic control of ferrous impurities for construction materials was noted. Especially it is important because of magnetic separators which are widely used for elimination of these impurities. There were shown the necessity of upgrading the present approach in order to realize the method of magnetic control. For example, it is necessary to take into account not only the rest of ferrous impurities (that is inevitable after limited numbers of operations) but also a factor of involving sand particles. The concrete proposal how to develop the existing system of magnetic control of ferrous impurities in construction materials subjected to magnetic separation, is stated. The experimental-calculation model for such control is also shown. The main parameters of such model were estimated on the example of quartz sand and feldspar. The errors of standard methods of magnetic control were revealed for the first time. 10.5862/MCE.38.3 ferrous impurities magnetic control experimental-calculation model https://engstroy.spbstu.ru/article/2013.38.3/ 03.pdf

RAR RUS 29-35 South Ural State University Chernykh Tamara chernyhtn@gmail.com South Ural State University Orlov A. South Ural State University Kramar L. South Ural State University Trofimov B. Chelyabinsk State University Perminov A. Temperature reduction during brucite-based magnesia cement production The article considers the problem of reducing the energy consumption during the production process of magnesia cement based on brucite admixed with serpentine, because this solid requires roasting at high temperatures (1100–1200°C). It was demonstrated that the most effective way to increase the energy efficiency of the technology is to use additives, so that roasting intensifiers. We investigated the effect of various additives and intensifiers to reduce the roasting temperature of serpentinized brucite material. We found that the most effective additives are those, destabilizing a crystal lattice of roasted solid and simultaneously producing the hot melt during their dehydration. It was shown that the highest temperature can be reduced by 100–300°C without increasing the heat treatment time. We also estimated the quality of magnesia cement obtained by the developed method and confirmed its compliance with all relevant regulations. 10.5862/MCE.38.4 brucite serpentine roasting magnesium oxichloride cement (MOC) temperature additives intensifiers energy efficiency https://engstroy.spbstu.ru/article/2013.38.4/ 04.pdf

RAR RUS 36-42 Moscow State University of Civil Engineering Adamtsevich Aleksey MnSpecter@gmail.com National Research Moscow State Civil Engineering University Pashkevich Stanislav PashkevichSA@mgsu.ru National Research Moscow State Civil Engineering University Pustovgar Andrey nsm.mgsu@mail.ru Application of calorimetry for prognosticating strength increase of fast-curing cement systems The most important characteristic of building materials and products based on cement is the strength after 28 days of hardening under normal conditions. Currently, however more and more attention is paid to development of fast-curing systems, resulting in need for analyzing the kinetics of hardening cement systems in early stages. Article presents the results of experimental researches of determination the relationship between growth strength of cement-sand mixture and amount of heat power released during hydration pure cement. And also the effectiveness of accelerating admixture for cement systems is established by comparing the heat release curve obtained for modified composition and similar curve obtained for control composition. In the course of present work it was revealed that for two cement systems differing only in presence of monofunctional accelerator it is possible to compare indirectly the growth dynamics of strength through integral heat flow curve during hydration binder and using the isothermal calorimetry. This demonstrates the possibility to simplify selection the optimal accelerating admixture in development of concrete mix and other building mixes by using methods presented in the article. 10.5862/MCE.38.5 calorimetry hydration cement accelerating admixtures concrete strength curing kinetics https://engstroy.spbstu.ru/article/2013.38.5/ 05.pdf

RAR RUS 43-50 Peter the Great Saint Petersburg Polytechnic University Abdullayev Gasym

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Velichkin Viktor V.Velichkin2011@yandex.ru

Polytechnicheskay, 29

Peter the Great St. Petersburg Polytechnic University Soldatenko Tamara soldatenko_tn@bk.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

The organizational and technological reliability improvement in construction by using failure prediction method The study shows how to assess the schedule reliability with available reserves of time in noncritical operations. The basis for assessing the reliability is the probability index of plan fulfillment, which is calculated according to known methods based on the beta-distributed random variables. The critical path operations postulate the highest probability of failures. Time reserves in non-critical operations of private flows have a compensating effect on the impact of the failures (delays) occurred on the critical path. The appropriate dependence for accounting time reserves in non-critical operations and calculated values of probability is proposed. In case of necessity of increasing the level of organizational and technical reliability the technique of changing the order of development of particular fronts based on the prediction of possible failures is proposed. The necessary computational techniques are given. 10.5862/MCE.38.6 planned schedule resource reserves reliability level organizational and technological reliability probability index failure and rejection refusals https://engstroy.spbstu.ru/article/2013.38.6/ 06.pdf

RAR RUS 51-58 Peter the Great Saint Petersburg Polytechnic University Letova Tatyana cool.letova@yandex.ru

Polytechnicheskay, 29

6602693779 Peter the Great St. Petersburg Polytechnic University Petinov Sergey sergei.petinov@gmail.com

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

Fatigue assessment of load-carrying welded cruciform joints T-form and cruciform joints in which the stress flow is transferred via weld material are widely applied in welded structures. A special type of these joints is presented by fillet-welded joints with incomplete penetration used by economical and manufacturing reasons. At a certain width of the cavity it becomes an active notch which in current design rules is regarded as an initial crack. In that way, fatigue life of the joint is characterized by the crack extensions towards the outer surface of weld bead. Fatigue assessment of these joints requires reliable data on the stress intensity factors values along the crack path. The results of systematic FEA-based calculations of stress intensity factors and respective S-N curves for the considered welded joints are presented. Main results obtained during this investigation can be used in solution of engineering tasks in reference to the fatigue assessment of welded cruciform joints with incomplete penetration. 10.5862/MCE.38.7 welded joints with incomplete penetration fatigue of welded joints FE-based analysis of welded joints with cracks stress intensity factors along the crack path S-N curves for welded joints with incomplete penetration https://engstroy.spbstu.ru/article/2013.38.7/ 07.pdf

RAR RUS 59-64 Ufa State Petroleum Technological University Vakhitov R. Baumit Ltd Samoilov A. Ufa State Petroleum Technological University Rezvov Oleg ufaoleg@bk.ru 7004630127 Ufa State Petroleum Technological University Babkov Vadim babkov.ugntu@gmail.com

1, Kosmonavtov St., Ufa, Russia, 450062

Ufa State Petroleum Technological University Gafurova Elina elina_gafurova@mail.ru Ufa State Petroleum Technological University Kuznetsov D. Ufa State Petroleum Technological University Sinitsin D. Georekon JSC Kildibaev Rinat rbstroi@mail.ru Deformability of plastering compositions in design solutions of modern thermal protective exterior walls In recent years, appearance of new constructive decisions for multilayer thermal efficient walls in the practice of design and construction caused the increasing use of protective and decorative plaster compositions. Comprehensive protective plaster systems nowadays are used in the facade insulation systems as a protective layer on the surface of polystyrene foam or mineral wool boards, forming the insulating layer to the outer walls of concrete blocks. They are also used for exterior finish of walls made of gas-concrete blocks, plastering the brickwork of the buildings operated by rehabilitation, in particular, apartment houses of old mass series. The problem of ensuring durability of thermal efficient external walls with the use of protective and decorative plaster systems were identified in this article. The factors, affecting the resistance of facade plasters to the action of external conditions in operating process were considered. The weaknesses in the necessary characteristics of plaster mixtures provided by material manufacturers are revealed. The existing methods for determining crack resistance of plaster compositions are monitored. The author's method of determining the maximum stretch of plaster compositions is given. The article presents tests results of various plaster compositions, confirming the effectiveness of the proposed method. 10.5862/MCE.38.8 thermal efficiency of the exterior walls of buildings facade plaster system deformability of plastering compositions https://engstroy.spbstu.ru/article/2013.38.8/ 08.pdf