АНАЛИТИЧЕСКИЕ ЗАВИCИМОСТИ ПРОЧНОСТНЫХ, ДЕФОРМАТИВНЫХ, СИЛОВЫХ И ЭНЕРГЕТИЧЕСКИХ ПАРАМЕТРОВ ВЫСОКОПРОЧНОГО БЕТОНА ПРИ НАГРЕВЕ

The paper presents experimental results of mechanical high strength concrete (HSC) properties at high temperature. The obtained results specify an increasing of strength and destruction energy of samples at temperature from 20 °С to 300 °С. The positive influence of high temperature (up to 400 °C) on concrete mechanical properties with w/c ratio less than 0.3 has been proved in the paper. The paper has experimentally proved that usage of a mineralogical additive as «silica fume» in high strength concrete at high temperatures often leads to an explosive destruction of every third sample. Changes in fracture toughness, crack resistance, specific energy consumption on quasi-static destruction have been described in mathematic formula.Статья представляет экспериментальные результаты механических свойств высокопрочного бетона (ВПБ) в условиях высокотемпературного нагрева. Полученные результаты указывают на возрастание прочности и энергии разрушения образцов при температурах от 20 до 300 °С. Подтверждено положительное влияние высокой температуры (до 400 °С) на механические свойства бетона с водоцементным отношением менее 0,3. Экспериментально доказано, что использование в высокопрочном бетоне минералогической добавки типа «микрокремнезем» в условиях высоких температур приводит к взрывному растрескиванию каждого третьего образца. Изменение вязкости разрушения, трещиностойкости, удельных энергозатрат на квазистатическое разрушение описывается математическими выражениями

Assessment of Concrete Resistance of Restored Reinforced Concrete Structures to Exposure to High Temperatures

Секция II : Строительные конструкции зданий и сооружений, современные методы расчета и проектированияНа основе анализа экспериментальных исследований предложены критерии хрупкости для высокопрочного бетона при высоких температурах и рекомендованы их пороговые значения, которые определяются по разработанной методике для бетона при t=20 оС. Новым в актуальной редакции ГОСТ 29167 является то, что определяемые по настоящему стандарту характеристики трещиностойкости применяют для оценки стойкости к воздействию высоких температур, используя силовые критерии механики разрушения – коэффициенты интенсивности напряжений при нормальном отрыве KIС.=On the basis of the analysis of experimental studies, brittleness criteria for high-strength concrete at high temperatures are proposed and their threshold values are recommended, which are determined by the developed method for concrete at t=20°C. New in the current version of GOST 29167 is that the fracture toughness characteristics determined according to this standard are used to assess the resistance to high temperatures using the force criteria of fracture mechanics - stress intensity factors for normal separation KIC

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2 females - abstract. Figure on left black face, jug on head; figure at right yellow face. Chest and Poster.ior prominent. Insc: To Lilian and Joe Marks in memory of your visit in Jerusalem from Hava and Abraham Yaari and the artist P. Litvinovsky 1957.Digital imagedigitize

ПРОПОЗИЦІЇ ЩОДО УДОСКОНАЛЕННЯ ПЛАНУВАННЯ ПРОДОВОЛЬЧОГО ЗАБЕЗПЕЧЕННЯ ПІДРОЗДІЛІВ ЗБРОЙНИХ СИЛ УКРАЇНИ ПІД ЧАС ПІДГОТОВКИ І В ХОДІ ВЕДЕННЯ БОЙОВИХ ТА ІНШИХ ДІЙ

The article presents a model of food supply planning for units of the Armed Forces of Ukraine while preparation and conduction of combat actions, propositions for the using and addition to the Guidelines for Logistic Support (Military Logistics), Combat Manuals of Mechanized and Tank Forces of the Ground Forces of the Armed Forces of Ukraine, Methodological (Training) Manuals and Methodological Recommendations for the Logistics of the Armed Forces of Ukraine on Improving the Planning of Food Supply for the Armed Forces for the Armed Forces of Ukraine during the preparation and conduction of military and other operations, considering the experience of the Anti Terrorist Operations (Joint Forces Operations). The Combat manual of the Mechanized and Tank Forces of the Ground Forces of the Armed Forces describes the methods, sequence and content of the work of the unit commander and partially for the deputy commander in logistics of the unit. For the heads of the logistics services, planning units for providing logistics services, namely, the sequence and content of their work during the preparation and conduction of combat and other operations, were not considered in any of the above mentioned documents. The article discusses versions for improving the planning of food supply units, namely, from the sequence, the content of the work of the head of the food service during the preparation and conduction of combat and other actions, which are developed on the basis of the listed regulatory documents and other sources of information. Exactly, the development of propositions for improving the planning of food supply for units during the preparation and conduction of combat and other operations was carried out by analyzing the content of these regulatory documents in the work of the logistical control facility of the military units (subunits) of the Armed Forces in a special period. As a result of the analysis of these regulatory documents and other sources of information, propositions on the sequence and content of the work during the preparation for combat and other operations were submitted. Propositions for the order of planning the food supply of units during the preparation and conduction of combat and other actions that are presented in the work should be used in the future when developing regulatory documents on the management activities of logistics management bodies (logistics, logistics services).У статті запропонована модель планування продовольчого забезпечення підрозділів Збройних Сил України під час підготовки і в ході ведення бойових та інших дій, надані пропозиції стосовно впровадження доповнень до Настанови з логістичного забезпечення (військового тилу), бойових статутів механізованих і танкових військ Сухопутних військ Збройних Сил України, методичних (навчальних) посібників і методичних рекомендацій Тилу Збройних Сил України щодо удосконалення планування продовольчого забезпечення військовослужбовців підрозділів Збройних Сил України під час підготовки і в ході ведення бойових та інших дій з урахуванням досвіду АТО (ООС)

Multi-stage emplacement of alkaline and peralkaline syenite-granite suites in the Mongolian-Transbaikalian Belt, Russia : evidence from U-Pb geochronology and whole rock geochemistry

The Mongolian–Transbaikalian Belt (MTB) is the largest and most representative component of the Central-Asian network of Late Paleozoic and Mesozoic granites and syenites and associated volcanic rocks. The MTB incorporates over 350 individual plutons and numerous volcanic fields, predominantly of alkaline and peralkaline composition. We present new U–Pb zircon and titanite geochronological data from five plutonic complexes located in the central part of the MTB. Four of them (Bryansky, Khorinsk, Kharitonovo and Malo-Kunalei) are peralkaline and alkali-feldspar granitoids, and one plutonic complex (Ust-Khilok) represents a shoshonitic series (K-rich gabbro, monzonite and syenite). The new data confirm the presence of three distinct stages of highly alkaline magmatic activity within the MTB: Early Permian (280–275 Ma), Late Triassic (230–219 Ma) and Late Jurassic ( 152 Ma). The dated shoshonitic plutonic complex formed between 280 and 278 Ma, overlapping with the formation of the Early Permian alkali-feldspar–peralkaline granitoid rocks. The ages of the alkali-feldspar and peralkaline magmatic suites are indistinguishable within a single magmatic complex. This suggests that several episodes of syenite and granite magma emplacement occurred within < 2 myr intervals. The close association in space and time of geochemically distinct igneous rocks points to co-existence of discrete magma chambers comprising magma from different sources. Early Permian magmatic activity in the MTB completed a continuous post-collisional cycle of magmatism that started in the Carboniferous (at 330 Ma) and lasted for about 50 myr. The Late Triassic stage marks the beginning of anorogenic tectonic setting in the MTB evolution. Late Jurassic peralkaline magmatism in the territory of the MTB is related to the formation of Mesozoic metamorphic core complexes, which are abundant in northern Mongolia and Transbaikalia and formed in an anorogenic within-plate environment