scholarly journals DETERMINATION OF MECHANICAL PROPERTIES OF REPAIR MORTARS USING IN SITU METHODS UNDER DIFFERENT CURINGS

2020 ◽  
Vol 2 ◽  
pp. 3-18
Author(s):  
Ali Saberi Varzaneh ◽  
Mahmoud Naderi
Keyword(s):  
Mechanical Properties ◽  
Concrete Structures ◽  
High Impact ◽  
Physical Factors ◽  
High Confidence ◽  
In Situ Methods ◽  
Repair Mortars ◽  
Friction Transfer

Considering the differences between environmental conditions of concrete structures and laboratory conditions, it is important to determine the parameters of the materials at the site of the structure. One of these materials is cement-based repair mortars due to the damage of concrete structures that may arise due to chemical or physical factors, these structures are required to be repaired. For this reason, in this paper, to determine the strength of repair mortars of different ages and under different Curing, Situ methods "Friction-Transfer" and "Pull-off" were used and the relationships between the Flexural Compressive, Tensile and readings obtained from the above methods on cementations mortars are presented. Experiments were performed on mortars at ages 3, 7, 28, 42 and 90 days under the conditions of "waterlogging", "Curing Agent" and "releasing in the outdoor". The results show the high impact of the process on the Flexural Compressive, Tensile of the repair mortars and the results of the "Friction-Transfer" and "Pull-off" methods. Also, a high correlation coefficient was obtained between the mechanical properties of the mortars and the results of the above tests; it is possible to measure the mechanical properties of repair mortars in situ with high confidence and in situ

A Novel In-Situ Nanoindentation Characterization of Phase Transforming Materials

2015 ◽  
Vol 1754 ◽  
pp. 19-24
Author(s):  
A. Alipour Skandani ◽  
R. Ctvrtlik ◽  
M. Al-Haik
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Creep Compliance ◽  
Physical And Mechanical Properties ◽  
In Situ Methods ◽  
Negative Creep ◽  
Nanoindentation Instrument ◽  
Structural Instabilities

ABSTRACTMaterials with different allotropes can undergo one or more phase transformations based on the changes in the thermodynamic states. Each phase is stable in a certain temperature/pressure range and can possess different physical and mechanical properties compared to the other phases. The majority of material characterizations have been carried out for materials under equilibrium conditions where the material is stabilized in a certain phase and a lesser portion is devoted for onset of transformation. Alternatively, in situ measurements can be utilized to characterize materials while undergoing phase transformation. However, most of the in situ methods are aimed at measuring the physical properties such as dielectric constant, thermal/electrical conductivity and optical properties. Changes in material dimensions associated with phase transformation, makes direct measurement of the mechanical properties very challenging if not impossible. In this study a novel non-isothermal nanoindentation technique is introduced to directly measure the mechanical properties such as stiffness and creep compliance of a material at the phase transformation point. Single crystal ferroelectric triglycine sulfate (TGS) was synthetized and tested with this method using a temperature controlled nanoindentation instrument. The results reveal that the material, at the transformation point, exhibits structural instabilities such as negative stiffness and negative creep compliance which is in agreement with the findings of published works on the composites with ferroelectric inclusions.

In-situ methods for the determination of current distributions in PEM fuel cells

1998 ◽  
Vol 43 (24) ◽  
pp. 3773-3783 ◽  
Author(s):  
Jürgen Stumper ◽  
Stephen A. Campbell ◽  
David P. Wilkinson ◽  
Mark C. Johnson ◽  
Mike Davis
Keyword(s):  
Fuel Cells ◽  
Pem Fuel Cells ◽  
Current Distributions ◽  
In Situ Methods

scholarly journals Study of Physical and Mechanical Properties of Centrifuged Concrete

2019 ◽  
Vol 18 (4) ◽  
pp. 319-329
Author(s):  
I. I. Palevoda ◽  
S. M. Zhamoidzik ◽  
D. S. Nekhan ◽  
D. S. Batan
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Cross Section ◽  
Outer Layer ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Physical And Mechanical Properties ◽  
Concrete Mixture ◽  
Density Analysis

The paper presents a complex of laboratory and theoretical studies of physical and mechanical properties in centrifuged concrete while using samples of sectoral cross-section which are cut in layers from a finished product. A post made of concrete having B40 grade for compression strength and manufactured while using centrifugation with the help of РТЦ-5 machine. Assessment of heterogeneity across section thickness has been carried out by visual determination of composition changes in cross section, determination of strength, density of the obtained concrete samples, and water content over cross section of concrete mix. According to the results of a visual study on composition of a concrete structure it has been revealed that 1/8 part of the structure (from an inner surface) does not have a large aggregate. Later, as it moves to periphery, there is an increase in coarse aggregate and a decrease in size and number of cells between grains of gravel. An analysis of experimental data has shown that properties of the centrifuged concrete in samples being sawn in layers change significantly: density of concrete in samples of an inner layer is lower by 8 % than in samples of an outer layer, and compressive strength of concrete – by 34 %, water content of concrete mixture of samples of the inner layer has turned out to be by 43 % higher than in samples of the outer layer. Approximating curves showing regularities of changes in density, concrete strength, water content of concrete mixture over thickness have been constructed in the paper. Linear and exponential equations have been obtained that describe changes in physical and mechanical properties of centrifuged concrete over section depending on structure properties as a whole, which, taking into account the obtained correction factors k1 and k2, can be used with an acceptable level of confidence in practical calculations of centrifuged concrete structures. Relationship between strength of centrifuged concrete varying over cross section and action of a centrifugal force of inertia has been revealed in the paper. An equation has been obtained that relates the strength of centrifuged concrete to its density. Analysis of the research results makes it possible to assert that the main source of loading perception in centrifuged concrete structures is outer layers.

Measuring Thermo-Mechanical Properties of Cometary Surfaces: In Situ Methods

2002 ◽  
pp. 269-282 ◽  
Author(s):  
Norbert I. Kömle ◽  
Günter Kargl ◽  
Karsten Seiferlin ◽  
Wojiech Marczewski
Keyword(s):  
Mechanical Properties ◽  
In Situ Methods

Static X-Ray Scans on the Titanium Hydride (TiH2) Powder during Dehydrogenation

2013 ◽  
Vol 795 ◽  
pp. 124-127 ◽  
Author(s):  
Nur Farhana Hayazi ◽  
Yu Wang ◽  
Mohd Noor Mazlee ◽  
Sammy Lap Ip Chan
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Isothermal Heating ◽  
X Ray ◽  
Refinement Method ◽  
Increasing Temperature

This work investigates the dehydrogenation of TiH2 powder during isothermal heating at 600°C using the static x-ray scans of high temperature x-ray diffraction (XRD). As-received TiH2 powder with a particle size of 5 μm and purity of 99.1% was used for this measurement. With increasing temperature, phase transformations occurred because of dehydrogenation and it happened very fast. It was found that during the phase transformation of TiH2 to titanium, some transitional phases observed and occurred. This finding confirmed the in-situ determination of TiH2 powder dehydrogenation by using Rietveld Refinement Method from our previous research. This study is useful for the fabrication of titanium-based composites and titanium alloys from TiH2 powder because the different phases in TiH2 will affect the final mechanical properties in titanium.

scholarly journals Influential Factors and Determination of strength of in-situ concrete, using twist-off method.

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Pooria Najarbashi ◽  
Mahmoud Naderi
Keyword(s):  
Low Cost ◽  
Concrete Strength ◽  
Influential Factors ◽  
Laboratory Methods ◽  
Significant Difference ◽  
Site Evaluation ◽  
In Situ Methods ◽  
Very High

Concrete strength represents by far the most critical property of concrete. It represents the mechanical properties of concrete. On-site evaluation of concrete strength remains the fundamental challenge in the condition assessment of existing infrastructure. Although standard laboratory methods can be typically used but most of these testing methods are costly and time-consuming. Among the in-situ methods, the “twist-off ” method with very slight damage is genuinely a convenient, fast and also low-cost technique that provides accurate results for engineers. In this study, the twist-offmethod has been used for the assessment of in-situ strength of the 30 concrete structures in Qazvin in Iran. The results showed structures studied had a strength of 45 to 600 kg/cm2 and the average is about 200 kg/cm2. The observed variation is very high, as well as a significant difference between the compressive strength of the columns, and the floors of the buildings that all indicate non-standard concrete mixing and inadequate control over construction. However, according to the past experience and results of the samples, some recommendations in this regard have been suggested.

Determination of mechanical properties of artificial turf football pitches according to structural components

2017 ◽  
Vol 232 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Javier Sánchez-Sánchez ◽  
Pascal Haxaire ◽  
Jorge García Unanue ◽  
José L Felipe ◽  
Ana M Gallardo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Parameters ◽  
Base Material ◽  
Structural Components ◽  
Artificial Turf ◽  
Force Reduction ◽  
Pile Length ◽  
Selection Of

Structural components of artificial turf football pitches have been improved in the last decade. The aim of this study was to explore the influence of structural components on the in situ mechanical behaviour of third-generation artificial turf football pitches. In total, 21 pitches were analysed according to the specified FIFA procedures. The results revealed that each of the pitches complies with the requirements of FIFA regulations. Pile length sample, stabilising bulk density, tuft/m2 and sub-base material all demonstrated a significant influence on the mechanical properties of the surface ( p < 0.05). Finally, the selected structural parameters explained 77.9%, 59.8% and 54.3% of variance in rotational traction, vertical deformation and force reduction, respectively. These results show the importance of the selection of the structural components in the design of artificial turf football pitches.

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