scholarly journals Influence of Carbonization of Concrete Surfaces on their Adhesion with Freshly-Laid Concrete

2021 ◽  
Vol 20 (4) ◽  
pp. 320-328
Author(s):  
V. V. Molodin ◽  
A. E. Anufrieva ◽  
S. N. Leonovich
Keyword(s):  
Carbon Dioxide ◽  
Surface Layer ◽  
Far East ◽  
Cement Stone ◽  
Reinforced Concrete Structures ◽  
Accelerated Tests ◽  
Aggressive Environment ◽  
The Far East ◽  
Scanning Electron ◽  
Reliable Basis

During operation, concrete and reinforced concrete structures are exposed to the aggressive environment of carbon dioxide. During the reconstruction and overhaul of the berthing facilities in the coastal zone of the seas of the Far East, a weak bond strength of the “old” carbonated and “new” repair concrete has been established in the paper. The reason that prevents reliable adhesion of concrete is the formation of fragile corrosion products in the pores and on the surface of “old” concrete. Accelerated tests of concrete carbonization from exposure to carbon dioxide have been carried out in the course  of the study. The structure of the carbonized cement stone has been examined using a scanning electron microscope. The research results have made it possible to assess the structure of a “healthy” cement stone and affected by carbonization.  The performed analysis of concrete carbonization process, including micrographs of the samples, has shown that under the action of carbon dioxide, the surface layer with a thickness of 4 mm and more undergoes structural restructuring. Fibrous formations are destroyed, and the carbonized volume is a heap of loosely bound loose new formations and films blocking the entrances to the capillary system of concrete. They are not a reliable basis for adhesion of “new” and “old” concrete and prevent the penetration of liquid containing cement dissolution products from “new” concrete into the capillaries of the healthy structure of the “old” concrete for their reliable connection.

scholarly journals PROBABILISTIC ANALYSIS OF DEPTH AND CARBONATION FRONT DEVELOPMENT IN CONCRETE OF MARINE STRUCTURES

2018 ◽  
Vol 17 (2) ◽  
pp. 106-113
Author(s):  
E. E. Shalyi ◽  
L. V. Kim ◽  
S. N. Leonovich ◽  
A. V. Stepanova
Keyword(s):  
Reinforced Concrete ◽  
Seasonal Change ◽  
Far East ◽  
Concrete Structures ◽  
Amur Region ◽  
Reinforced Concrete Structures ◽  
The South ◽  
The North ◽  
The Far East ◽  
The Impact

On the coast of the Russian Far East the climate is monsoon, which is most pro-nounced in the south and northeast waning. Seasonal change of oceanic and continental influence is reflected in the nature of the climate: summer is moderatelywarm and rainy, winter is cold and snowy. On Sakhalin winters are less severe than on the mainland. In Kamchatka, where the winters are milder, the influence of the continental monsoon less. In the southern part of Primorye snow is so small that there is in the rivers spring flood. In the north of the Amur region, Sakhalin, Kamchatka rainfall and snowpack increases. In the summer is dominated by southeast wind, which spread to the continent moist Pacific air. During the year, between the Pacific Ocean and the south of the Far East there is an intensive exchange of air masses. Seasonal change of air currents is determined by the thermal contrast between the continent and the ocean. During the year passes over the area to an average of 100 cyclones (3–6 per month during the cold period, and up to 3 – warm), which are ac-companied by increased wind, cloudy weather with precipitation, and in late summer and early au-tumn, typhoons observed outputs. Typhoons are accompanied by stormy winds reaching speeds of over 40 m / sec. and heavy rains. A wide variety of observed in the distribution of precipitation. The Chukchi-Anadyr area for the warm period falls to 200–250 mm in the north of the Sea of Okhotsk – 400–500 mm, in intermountain basins up to 250–300 mm. To the south the amount of precipitation increases to 500 to 600 mm in the Amur region and 900–1000 mm on the western slopes of Sikhote Alin. In the course of the annual maximum rainfall in the second half of the summer, but there are rainy June and September. No wonder that in such conditions, corrosion, material of hydraulic structures is most intense. Concrete and cement stone reinforced concrete structures exposed to corrosive attack, particularly the aggressive action of CO2 common acid gas, which is to neutralize the surface layer of concrete and the formation of the compounds that affect its properties. The article discusses the impact of the environment model south of the Far East, mainly due to the impact on hydraulic reinforced concrete structures of carbon dioxide in the environment, with subsequent corrosion of concrete and reinforcement.

RARE HYDNOID FUNGUS HYDNELLUM GEOGENIUM (FR.) BANKER (THELEPHORALES, BASIDIOMYCOTA) IN THE FAR EAST OF RUSSIA

2020 ◽  
Vol 68 ◽  
pp. 127-133
Author(s):  
N.V. Bukharova ◽  
◽  
E.M. Bulakh ◽  
V.M. Kazarin ◽  
◽  
...  
Keyword(s):  
Far East ◽  
Far East Of Russia ◽  
Fruiting Bodies ◽  
The Far East ◽  
Natural Reserve ◽  
Kunashir Island ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Far Eastern ◽  
Scanning Electron

Hydnellum geogenium is a hydnoid fungus of Bankeraceae, easily recognizable by the specific yellow-greenish color of fruiting bodies. It is widespread, but is rare everywhere. In the Far East of Russia, it is known only from two localities: Botchinsky Natural Reserve (Khabarovsk Territory) and Kunashir Island (Sakhalin Region). The author’s description of the Far Eastern samples, as well as photographs of microstructures on light and on scanning electron microscopes, are given.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Is there a regional culture in Russia? Opportunities of using a sociocultural approach in economics

2020 ◽  
pp. 108-126 ◽  
Author(s):  
V. A. Bryzgalin ◽  
Е. N. Nikishina
Keyword(s):  
Far East ◽  
Cross Cultural ◽  
Regional Culture ◽  
Russian Regions ◽  
Geographical Patterns ◽  
Cross Cultural Differences ◽  
The Far East ◽  
Sociocultural Approach ◽  
Critical Issues ◽  
Russian Universities

The paper investigates cross-cultural differences across Russian regions using the methodology of G. Hofstede. First, it discusses the most common approaches in measuring culture and the application of the Hofstede methodology in subnational studies. It identifies the critical issues in measuring culture at the regional level and suggests several strategies to address them. Secondly, the paper introduces subregional data on individualism and uncertainty avoidance using a survey of students across 27 Russian universities. The data allow to establish geographical patterns of individualism in Russia. It is demonstrated that collectivism is most prevalent in the Volga region, while individualism characteristic becomes stronger towards the Far East. The findings are robust to the inclusion of various controls and different specifications of the regression model. Finally, the paper provides a discussion about the potential of applying the sociocultural approach in economics.

The Portuguese Possessions in the Far East

1937 ◽  
Vol 6 (4) ◽  
pp. 45-47
Author(s):  
R. G. S.
Keyword(s):  
Far East ◽  
The Far East
Sign in / Sign up

Export Citation Format

Share Document