A multiscale model for modulus of elasticity of concrete at high temperatures

Paper describes properties of cement paste included addition of the fly ash. Firstly is described the preparation of the cement paste. Next part is focused on the testing of the properties. Results of the testing are summarized in properties like a compression strength, Modulus of elasticity and strength in bending. Finally the relation between material properties and volume weight is discussed. An article is described paste made from the same amount of cement and fly ash and water coefficient of 0.4.

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Compression Strength and Modulus of Elasticity Parallel to the Grain of Oak Wood at Ultra-low and High Temperatures

BioResources ◽

10.15376/biores.9.2.3571-3579 ◽

2014 ◽

Vol 9 (2) ◽

Cited By ~ 6

Author(s):

Jinghui Jiang ◽

Jianxiong Lu ◽

Yongdong Zhou ◽

Youke Zhao ◽

Liyuan Zhao

Keyword(s):

High Temperatures ◽

Compression Strength ◽

Modulus Of Elasticity ◽

Oak Wood

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Influence of the Maximum Aggregate Grain Size on the Modulus of Elasticity and on the Parameters of the Acoustic Emission of Concrete Exposed to High Temperatures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.276.134 ◽

2018 ◽

Vol 276 ◽

pp. 134-139

Author(s):

Libor Topolář ◽

Dalibor Kocáb ◽

Michaela Hoduláková ◽

Romana Halamová

Keyword(s):

Acoustic Emission ◽

High Temperatures ◽

Modulus Of Elasticity ◽

Building Materials ◽

Emission Method ◽

High Rise ◽

Grain Sizes ◽

Static Modulus ◽

Internal Structures ◽

Static Modulus Of Elasticity

Several very large and tragic fires of buildings have occurred recently, drawing attention to the issues of fire resistance of buildings (especially high-rise buildings and tunnels) and of building materials. For cement-based composites, it is essential to comprehensively understand the behaviour of their internal structures when exposed to high temperatures. This paper deals with the changes of the physical properties of concrete with different aggregate grain sizes when exposed to high temperatures. The emphasis is placed on the changes of the static and dynamic modulus of elasticity as an important parameter in assessing the behaviour of structures or their parts. During the test of the static modulus of elasticity, the acoustic emission method was also used as its results may reveal the behaviour of the internal structure of the material during mechanical loading.

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In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087616 ◽

1991 ◽

Vol 49 ◽

pp. 660-661

Author(s):

Z. L. Wang ◽

J. Bentley

Keyword(s):

High Temperatures ◽

Image Resolution ◽

Atomic Processes ◽

Crystal Surfaces ◽

Beam Radiation ◽

Surface Areas ◽

Transmission Electron ◽

Reflection Electron Microscopy ◽

Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

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