Effect of Hydration Temperature on Cement Paste Structure

1986 ◽  
Vol 85 ◽  
Author(s):  
I. Odler ◽  
S. Abdul-Maula ◽  
Lu Zhongya
Keyword(s):  
Phase Composition ◽  
Pore Structure ◽  
Cement Paste ◽  
Elevated Temperatures ◽  
Effect Of Temperature ◽  
Structure And Properties ◽  
Bond Properties ◽  
Portland Cements

ABSTRACTThe effect of temperature on the progress of hydration and cement paste structure and properties was studied using four laboratory-synthesized portland cements, hydrated at temperatures between 5 and 95°C for up to 90 days. In addition to an accelerated progress of hydration, elevated temperatures altered the phase composition and pore structure of the resulting hydrated material. Below 75°C the effect of temperature on the intrinsic bond properties of the hydrates formed remained negligible.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

The study of crystal-phase composition and pore structure for Dicaoqing-Zisha compared with porcelain and pottery

2020 ◽  
Author(s):  
Chunrui Yang ◽  
Jianyi Kong ◽  
Jiajing Yang ◽  
Chengliang Chu ◽  
Xingdong Wang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Pore Structure ◽  
Crystal Phase

Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Elevated Temperatures ◽  
Initial Material ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

Study on Relationship between Structure and Properties of Polycarboxylate Superplasticizer

2012 ◽  
Vol 487 ◽  
pp. 43-47
Author(s):  
Sheng Hua Lv ◽  
Di Li ◽  
Qiang Cao
Keyword(s):  
Acrylic Acid ◽  
Zeta Potential ◽  
Ethyl Ester ◽  
Functional Groups ◽  
Cement Paste ◽  
Ethyl Acrylate ◽  
Structure And Properties ◽  
Polycarboxylate Superplasticizer ◽  
Carboxylic Groups

A polycarboxylate superplasticizer (PCs) was synthesized by copolymerization of allyl polyoxyethylene ethers (APE), acrylic acid (AA), sodium methylallyl Sulfonate (SMAS) and ethyl acrylate (EA). The effect of functional groups and branch chain on PCs properties was investigated by the test of fluidity of cement paste, retardation performance and Zeta potential of cement particles. The results showed that carboxylic groups and ethyl ester groups can improve water reducing ratio and fluidity of cement paste, and the sulfonic groups has an important contributiion to retardation performance of PCs.

scholarly journals Deformation of Ordered Mesoporous Silica Structures on Exposure to High Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
John B. Lowe ◽  
Richard T. Baker
Keyword(s):  
Mesoporous Silica ◽  
Pore Structure ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Ordered Mesoporous Silica ◽  
Large Cage ◽  
Pore Structures ◽  
Ordered Mesoporous ◽  
Pore Size Distributions ◽  
Wide Range

Ordered mesoporous silica materials are of interest for a wide range of applications. In many of these, elevated temperatures are used either in the preparation of the material or during its use. Therefore, an understanding of the effect of high temperature treatments on these materials is desirable. In this work, a detailed structural study is performed on silicas with three representative pore structures: a 2-D hexagonal pore arrangement (SBA-15), a continuous 3D cubic bimodal pore structure (KIT-6), and a 3D large cage pore structure (FDU-12). Each silica is studied as prepared and after treatment at a series of temperatures between 300 and 900°C. Pore structures are imaged using Transmission Electron Microscopy. This technique is used in conjunction with Small-Angle X-ray Diffraction, gas physisorption, and29Si solid state Nuclear Magnetic Resonance. Using these techniques, the pore size distributions, the unit cell dimensions of the mesoporous structures, and the relative occupancy of the distinct chemical environments of Si within them are cross correlated for the three silicas and their evolution with treatment temperature is elucidated. The physical and chemical properties before, during, and after collapse of these structures at high temperatures are described as are the differences in behavior between the three silica structures.

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