Influence of Temperature on the Hydration Heat of Polymer Modified Mortars

2013 ◽  
Vol 687 ◽  
pp. 130-135
Author(s):  
Si Feng Liu ◽  
Si Jun Guo ◽  
Pei Ming Wang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Vinyl Acetate ◽  
Cement Mortar ◽  
Ethylene Vinyl Acetate ◽  
Hydration Heat ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Effects Of Temperature ◽  
Isothermal Calorimeter

The hydration heat of polymer modified mortar were measured at 5°C、10°C、20°C and 40°C using Multi-channel Isothermal calorimeter. The effects of temperature on hydration heat of polymer modified mortars with 0.1% methyl hydroxylpropyl cellulose (MHPC), 3% ethylene vinyl acetate (EVA) and 0.1%MHPC+3%EVA were investigated. The curves of hydration heat show that the polymer reduces the hydration heat of mortars and it is related to the temperature. The effects will be more and more remarkable with the increasing of temperature; Temperature also affects the exothermic rate peak of polymer modified mortars. The exothermic rate peak of polymer modified mortar at low temperature is almost equal to that of the ordinary cement mortar. However, it is obviously lower than that of ordinary cement mortar at high temperature ; The time to the exothermic rate peak of polymer modified mortar is also related to the temperature.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

scholarly journals Mechanical Degradation and Thermal Decomposition of Ethylene-Vinyl Acetate (EVA) Polymer-Modified Cement Mortar (PCM) Exposed to High-Temperature

2019 ◽  
Vol 11 (2) ◽  
pp. 500 ◽  
Author(s):  
Hyung-Jun Kim ◽  
Jae-Yeon Park ◽  
Heong-Won Suh ◽  
Beom-Yeon Cho ◽  
Won-Jun Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Compressive Strength ◽  
High Temperature ◽  
Vinyl Acetate ◽  
Cement Mortar ◽  
Ethylene Vinyl Acetate ◽  
Mechanical Degradation ◽  
Rc Structures ◽  
Cement Ratio

A polymer-modified cement mortar (PCM) is widely used as a repair material for reinforced concrete (RC) structures owing to its excellent strength and durability. However, considering the maintenance of the RC structures and the use period of the structures, the change in the physical properties of the PCM should be evaluated when exposed to various high-temperature environments, such as fires. In this study, the degradation of the mechanical properties (compressive strength and modulus of elasticity), thermal decomposition of the PCM in various high-temperature environments, and the change in the pore structure of the PCM after exposure to high temperatures were quantitatively investigated. A mechanical property evaluation of PCM was performed under three heating conditions: (i) heating in a compression tester, (ii) heating the specimen in an oven to a predetermined temperature and then moving it to a compression tester preheated to the same temperature, and (iii) cooling to room temperature after heating. In the experiment, a PCM specimen was prepared by changing the polymer–cement ratio (polymer content) of ethylene-vinyl acetate (EVA), the most commonly used polymer, to perform a high-temperature sectional test from 200 to 800 °C. In addition, to investigate the change in the PCM mechanical properties in the high-temperature region, in terms of the pyrolysis of EVA, the porosity change and mass change were examined using thermal analysis and mercury intrusion porosimetry. Before heating, the compressive strength of the PCM increased with the EVA content up to 10 % of the polymer–cement ratio. Under the cooling conditions after heating up to 200 °C, the mechanical performance of the PCM was restored, whereas the degradation of the mechanical properties of the PCM without cooling was more pronounced. Furthermore, the mass loss, heat flow, and the total porosity of the PCM increased as the EVA content increased, which is correlated with the degradation of the mechanical properties of the PCM.

scholarly journals The Influence of Temperature on the Completion of Diapause in the Eggs of Gryllulus Commodus Walker

1952 ◽  
Vol 5 (1) ◽  
pp. 112 ◽  
Author(s):  
TO Browning
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Early Stage ◽  
Morphological Development ◽  
Influence Of Temperature ◽  
Long Period ◽  
Influence Of Temperature On

The eggs of GryUulus commodus, if incubated at high temperature (26.8�C.), soon after laying, did not develop and hatch promptly. Instead hatching was spread over a long period and many eggs died. If the eggs were given a period of exposure to low temperature (12.8�C.) before incubation at high temperature,� prompt hatching occurred. This was due to diapause, which occurred at an early stage in the morphological development of the egg.

Diapause in the Eggs of Austroicetes cruciata, Sauss. (Acrididae) with particular Reference to the Influence of Temperature on the Elimination of Diapause

1943 ◽  
Vol 34 (1) ◽  
pp. 1-17 ◽  
Author(s):  
H. G. Andrewartha
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Influence Of Temperature ◽  
Temperature Range ◽  
Abnormal Growth ◽  
Inhibition Of Growth ◽  
Stage Of Development ◽  
Influence Of Temperature On ◽  
Temperature Ranges ◽  
The One

Diapause should not be confused with simple inhibition of growth due to cold.The embryo of the grasshopper, Austroicetes cruciata, enters a state of diapause a few days after the egg is laid. The diapause is obligate like that found in the eggs of Circotettix, rather than facultative like that found in the larvae of Platyedra. These types of diapause should be regarded as two extremes of the one phenomenon rather than two distinct phenomena.Diapause was eliminated when the egg was exposed to adequate low temperature for an adequate period when the embryo was at a suitable stage of development. If the period at low temperature was inadequate, or if the embryo was not at a suitable stage of development when the exposure to low temperature occurred, diapause was only partially eliminated. In such cases, the exposure to low temperature resulted in an abnormal growth by the embryo when the egg was returned to a favourable high temperature, but development was not completed.The influence of low temperature on the elimination of diapause was due chiefly to changes which occurred in the yolk during exposure to low temperature. Thus yolk which had been modified in this way became suitable for the nourishment of the embryo, and it no longer obstructed katatrepsis. This explanation of the nature of the obligate diapause in the eggs of Austroicetes brings this phenomenon into line with the facultative diapause in the larvae of Platyedra, which has been shown to be associated with the nourishment of the larva.Diapause was eliminated most rapidly at temperatures between 6°C. and 13°C. The embryo grew most rapidly at about 30°C. ; below 13°C. growth practically ceased. The absence of overlapping of the temperature ranges for these two processes may explain the presence of diapause in Austroicetes. The occurrence of a less pronounced diapause in the eggs of Melanoplus may be due to a partial overlapping of the temperature range for the two processes. Similarly the absence of diapause in the eggs of Locusta may be explained on the assumption that in this species the two processes proceed over the same temperature range.

scholarly journals Influence of Temperature on CO₂ and H₂S Corrosion Rates of Steel Pipelines Using Alloy-Select Software in the Lebanese Oil and Gas Offshore Environment

2021 ◽  
Vol 4 (2) ◽  
pp. 44-51
Author(s):  
Rawanne Farsakouri
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Corrosion Inhibitor ◽  
Significant Influence ◽  
Oil And Gas ◽  
Influence Of Temperature ◽  
Suitable Material ◽  
Corrosion Rates ◽  
Water Composition ◽  
Influence Of Temperature On

By referring to the fact that corrosion rates alter upon variation of different conditions and no research relevant to Lebanon address corrosion issues yet, this study was conducted based on accurate Lebanese offshore data and water composition. Based on "Alloy Select Software", identifying the most suitable material from different alloys was revealed, which turned out to be Copper and Aluminum based alloys. Moreover, corrosion rates were detected under different conditions of Temperature, CO₂, and H₂S and then repeated in the presence of a corrosion inhibitor. Results of these studies proved the significant influence of high temperature accompanied with high CO₂ percentage. However, different results concerning low temperature with different percentages of H₂S were obtained.

High-temperature coupling of high-speed GPC with continuous viscometry. II. Ethylene–vinyl acetate copolymers

1984 ◽  
Vol 29 (5) ◽  
pp. 1569-1579 ◽  
Author(s):  
D. Lecacheux ◽  
J. Lesec ◽  
C. Quivoron ◽  
R. Prechner ◽  
R. Panaras ◽  
...  
Keyword(s):  
High Temperature ◽  
Vinyl Acetate ◽  
High Speed ◽  
Ethylene Vinyl Acetate

Experimental Study on the Influence of Temperature on Shale Mechanical Properties under Conventional Triaxial Compression

2011 ◽  
Vol 250-253 ◽  
pp. 1452-1455 ◽  
Author(s):  
Lu Bo Meng ◽  
Tian Bin Li ◽  
Liang Wen Jiang ◽  
Hong Min Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
High Temperature ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Poisson's Ratio ◽  
Influence Of Temperature ◽  
Conventional Triaxial Compression ◽  
Influence Of Temperature On

High temperature conventional triaxial compression test of shale are carried out by the MTS815 servo-controlled testing machine, based on the experimental results, the relationships between temperature and shale peak strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle are investigated. Although the experimental results are discrete comparatively, the general law is obvious. When the confining pressure imposed on shale is constant and the temperature changes form 25°C to 120°C, with the increasing of the temperature, the triaxial compression strength, shear strength gradually increase, while average elastic modulus, Poisson's ratio has a slightly decrease. The thermal stress generated by the high temperature plays a role to accommodate the deformation and the function of preventing crack propagation, thus the bearing capacity of shale samples are strengthened. But the influence of temperature on shale mechanical properties mutates when the temperature is at 80°C. Shale peak strength dramatically decreased, average elastic modulus decreased slightly, and Poisson's ratio also increased slightly, which indicated that at 80°C, different thermal expansivity of mineral particles of shale may cause cross-grain boundary thermal expansion incongruous, creating additional thermal stress, thus the sample’s bearing capacity decreased.

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