scholarly journals Experimental Investigation for Tensile Performance of GFRP-Steel Hybridized Rebar

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Dong-Woo Seo ◽  
Ki-Tae Park ◽  
Young-Jun You ◽  
Sang-Yoon Lee
Keyword(s):  
Elastic Modulus ◽  
Concrete Structures ◽  
Tensile Tests ◽  
Test Results ◽  
Building Technology ◽  
Gfrp Bars ◽  
Low Elastic Modulus ◽  
Tensile Performance ◽  
The Individual

Tensile performance of the recently developed “FRP Hybrid Bar” at Korea Institute of Civil Engineering and Building Technology (KICT) is experimentally evaluated by the authors. FRP Hybrid Bar is introduced to overcome the low elastic modulus of the existing GFRP bars to be used as a structural member in reinforced concrete structures. The concept of material hybridization is applied to increase elastic modulus of GFRP bars by using steel. This hybridized GFRP bar can be used in concrete structures as a flexural reinforcement with a sufficient level of elastic modulus. In order to verify the effect of material hybridization on tensile properties, tensile tests are conducted. The test results for both FRP Hybrid Bar and the existing GFRP bars are compared. The results indicate that the elastic modulus of FRP Hybrid Bar can be enhanced by up to approximately 250 percent by the material hybridization with a sufficient tensile strength. To ensure the long-term durability of FRP Hybrid Bar to corrosion resistance, the individual and combined effects of environmental conditions on FRP Hybrid Bar itself as well as on the interface between rebar and concrete are currently under investigation.

scholarly journals Residual Capability of Alkali Binding by Hydrated Pozzolanic Cements in Long-Service Concrete Structures

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Mario Berra ◽  
Teresa Mangialardi ◽  
Antonio Evangelista Paolini
Keyword(s):  
Concrete Structures ◽  
Test Results ◽  
Cement Pastes ◽  
Experimental Procedure ◽  
Accelerated Curing ◽  
Alkali Aggregate Reaction ◽  
Simple Mass ◽  
Pore Liquid ◽  
Pozzolanic Cement

An experimental procedure was developed and applied to cement pastes made with two different pozzolanic cements (CEM IV/B (P) and CEM IV/B (V)) in order to ascertain the existence of a residual capability of alkali binding by long-term hydrated pozzolanic cements and, at the same time, to evaluate the alkali retention capability and the concentration of OH− ions in the pore solution of such cementitious matrices. The developed procedure consisted of accelerated curing of cement paste specimens (150 days at 60°C and 100% RH), subsequent leaching tests at 60°C for 30 days by using deionized water or basic solutions (NaOH or KOH at different concentrations) as leaching media, and correlation of the leaching test results with a simple mass balance equation for sodium and potassium ions. The developed procedure was found to be appropriate for evaluating both the pore liquid alkalinity and the alkali retention capability by long-term hydrated pozzolanic cement pastes. A residual capability of alkali binding was also identified for both tested pozzolanic cements, thus indicating their potential ability to prevent (CEM IV/B (V)) or minimize (CEM IV/B (P)) the risk of deleterious expansion associated with alkali-aggregate reaction in long-service concrete structures, like concrete dams.

scholarly journals Mechanical properties of blueberry stems

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 202-208
Author(s):  
Margus Arak ◽  
Kaarel Soots ◽  
Marge Starast ◽  
Jüri Olt
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Structural Parameters ◽  
Tensile Tests ◽  
Measuring Instrument ◽  
Test Results ◽  
Average Value ◽  
Agricultural Machines

In order to model and optimise the structural parameters of the working parts of agricultural machines, including harvesting machines, the mechanical properties of the culture harvested must be known. The purpose of this article is to determine the mechanical properties of the blueberry plant’s stem; more precisely the tensile strength and consequent elastic modulus E. In order to achieve this goal, the measuring instrument Instron 5969L2610 was used and accompanying software BlueHill 3 was used for analysing the test results. The tested blueberry plant’s stems were collected from the blueberry plantation of the Farm Marjasoo. The diameters of the stems were measured, test units were prepared, tensile tests were performed, tensile strength was determined and the elastic modulus was obtained. Average value of the elastic modulus of the blueberry (Northblue) plant’s stem remained in the range of 1268.27–1297.73 MPa.

scholarly journals Influence of Polypropylene Fiber on Tensile Property of a Cement-Polymer Based Thin Spray-On Liner

2019 ◽  
Vol 9 (14) ◽  
pp. 2876 ◽  
Author(s):  
Wei ◽  
Zhang ◽  
Feng ◽  
Xie ◽  
Wu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Polypropylene Fiber ◽  
Tensile Tests ◽  
Control Group ◽  
Load Direction ◽  
Low Elastic Modulus ◽  
The Matrix ◽  
Test Result ◽  
Tensile Toughness

The influence of a polypropylene fiber on the tensile properties of a cement-polymer based thin spray-on liner (TSL) was investigated in this study. Two different contents of fiber were added to the liner, yielding two TSL groups. Tensile tests were performed (in accordance with the ASTM D638 standard) on the two groups of specimens as well as the control group at 1, 7, 14, and 28-day curing. The test result verified the large plasticity and low elastic modulus of the TSL compared with the fiber. SEM examination revealed that fibers lying parallel to the load direction ruptured or were pulled out from the matrix, which was beneficial to the tensile strength, but detrimental to the elongation because of their high stiffness. Other fibers lying perpendicular with the load direction were detrimental to both tensile strength and elongation through aggravating the propagation of the cracks. The tensile strength was improved by fiber incorporation, while the elongation was reduced at all curing. The influence of fibers on tensile toughness was uncertain since tensile toughness depended on strength as well as deformity.

Tensile Properties of GFRP Bars after Exposure to Harsh Laboratory and Field Environmental Conditions

2011 ◽  
Vol 250-253 ◽  
pp. 3738-3742 ◽  
Author(s):  
Saleh Alsayed ◽  
Tarek Almusallam ◽  
Yousef Al-Salloum ◽  
Sherif El-Gamal
Keyword(s):  
Tensile Properties ◽  
Environmental Conditions ◽  
Sea Water ◽  
Tap Water ◽  
Harmful Effect ◽  
Tensile Tests ◽  
Field Conditions ◽  
Maximum Effect ◽  
Test Results ◽  
Gfrp Bars

This paper presents the test results of an experimental study that investigates the durability of a new generation of Glass Fiber Reinforced Polymer (GFRP) bars. A total of 60 GFRP bars were embedded in concrete prisms and exposed to ten environmental conditions for 6 and 12 months. The environments included exposure to ordinary tap water, sea water, and alkaline solution at two temperatures (room and 50°C). The environments also included two typical field conditions of the Kingdom of Saudi Arabia (Gulf area and Riyadh area). The performance of the GFRP bars was evaluated by conducting tensile tests on the bars extracted out of the concrete specimens after exposure to the environmental conditions. After 12 months of exposure, the test results showed that the tap water at 50°C had the maximum effect on the tensile strength of the GFRP bars. The two field conditions did not show any harmful effect on the tensile properties of the bars after 12 months of exposure.

Phase Transformation of Biomedical Metastable β Titanium Alloy during Aging

2009 ◽  
Vol 610-613 ◽  
pp. 1168-1173
Author(s):  
Ai Hong Guo ◽  
Wen Fang Cui ◽  
Yi Zhou Wu ◽  
Xiang Hong Liu ◽  
Lian Zhou
Keyword(s):  
Phase Transformation ◽  
Elastic Modulus ◽  
Biomedical Application ◽  
High Strength ◽  
Tensile Tests ◽  
High Plasticity ◽  
Aging Condition ◽  
Β Phase ◽  
Low Elastic Modulus ◽  
Strength And Plasticity

A kind of metastable β type Ti-30Nb-13Zr-0.5Fe (wt.%) alloy for biomedical application was newly designed and developed. In order to exam the phase transformation during aging and its effects on the mechanical properties, the alloy was β solubilized and aged at 350°C-550°C for 4 hours. The microstructures were observed by OM and TEM, and the phase structures were identified by XRD. The tensile tests were performed with various aged microstructures. The results show that a lot of ω phase precipitates during aging at 350°C, leading to the increase of strength and elastic modulus and drastic decrease of plasticity. Aging at 450°C, dot α phase uniformly precipitates from metastable β phase. The good combination of high strength 、high plasticity and low elastic modulus was obtained under this aging condition. With increasing aging temperature and aging time α precipitations coarsen and precipitation free zones (PFZ) along prior β grain boundaries form, which are the main reasons to lower the strength and plasticity.

scholarly journals Experimental Investigation of the Effects of Concrete Alkalinity on Tensile Properties of Preheated Structural GFRP Rebar

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hwasung Roh ◽  
Cheolwoo Park ◽  
Do Young Moon
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
High Temperature ◽  
Tensile Failure ◽  
Combined Effects ◽  
Test Results ◽  
Maximum Difference ◽  
Reinforcing Bars ◽  
Tensile Performance ◽  
Gfrp Bar

The combined effects of preexposure to high temperature and alkalinity on the tensile performance of structural GFRP reinforcing bars are experimentally investigated. A total of 105 GFRP bar specimens are preexposed to high temperature between 120°C and 200°C and then immersed into pH of 12.6 alkaline solution for 100, 300, and 660 days. From the test results, the elastic modulus obtained at 300 immersion days is almost the same as those of 660 immersion days. For all alkali immersion days considered in the test, the preheated specimens provide slightly lower elastic modulus than the unpreheated specimens, showing only 8% maximum difference. The tensile strength decreases for all testing cases as the increase of the alkaline immersing time, regardless of the prehearing levels. The tensile strength of the preheated specimens is about 90% of the unpreheated specimen for 300 alkali immersion days. However, after 300 alkali immersion days the tensile strengths are almost identical to each other. Such results indicate that the tensile strength and elastic modulus of the structural GFRP reinforcing bars are closely related to alkali immersion days, not much related to the preheating levels. The specimens show a typical tensile failure around the preheated location.

Sealing Performance of Pipe Flange Connections With Shape Memory Alloy Gaskets Under Internal Pressure

2004 ◽  
Author(s):  
Teruhisa Tatsuoka ◽  
Yoshio Takagi ◽  
Toshiyuki Sawa
Keyword(s):  
Elastic Modulus ◽  
Numerical Analysis ◽  
Low Temperature ◽  
Shape Memory ◽  
Strain Behavior ◽  
Sealing Performance ◽  
Low Elastic Modulus ◽  
Thermal Expansion Effect ◽  
Expansion Effect

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to give a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. On the other hand, shape memory alloys (SMA) like nickel-titanium (Ni-Ti) alloy have a super elasticity and an excellent deformation capability with relatively low elastic modulus as a metal. Therefore, Ni-Ti SMA is expected to show an excellent performance as a gasket. In order to evaluate the applicability of Ni-Ti SMA to gasket, experimental and numerical analysis were conducted in this study. As an experimental evaluation, the new gasket constants and the tightness parameter proposed by PVRC (Pressure Vessel Research Council) were measured by the leakage tests. The constants and the tightness parameter of Ni-Ti SMA gasket were superior to those of aluminum gasket. The numerical analysis revealed that the clamping temperature highly affected on the performance of Ni-Ti SMA gasket because the stress-strain behavior of Ni-Ti SMA strongly depended on the temperature. Since the Ni-Ti SMA has a softer phase at low temperature, e.g. less than 11°C (As point), the flange connection initially clamped at low temperature showed a higher sealing performance. In addition, the heat cycle test with the cycle of the initial clamp temperature (0 or 20°C) to 40°C also suggested that the lower clamp temperature yielded a higher contact force due to the thermal expansion effect.

The Effects on Tensile Properties of Different Winding Way on GFRP Bar

2013 ◽  
Vol 438-439 ◽  
pp. 357-360
Author(s):  
Yu Yang Pang ◽  
Pu Zhang ◽  
Dan Ying Gao ◽  
Fei Mo
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Modulus Of Elasticity ◽  
Tensile Tests ◽  
Test Results ◽  
Shear Properties ◽  
Gfrp Bars ◽  
Ultimate Elongation ◽  
Gfrp Bar ◽  
Gfrp Reinforcement

The influence of different surface forms on GFRP reinforcement mainly manifest in bonding between reinforcement materials and concrete, especially when the GFRP bars are used in slope, the form of the surface of GFRP bar will affect reinforced materials torsion and shear properties directly. This article made some tensile tests on several different surface forms of GFRP reinforcement, and learned that the form of the surface wound of GFRP bar make the influence on tensile strength, ultimate elongation and modulus of elasticity. Test results show that the surface of the winding way will affect on the tensile strength, ultimate elongation and modulus of elasticity of GFRP bar.

Parents' long-term adjustment to the genetic test results of minors at risk for Long QT Syndrome

2004 ◽  
Author(s):  
K. S. W. H. Hendriks ◽  
F. J. M. Grosfeld ◽  
A. A. M. Wilde ◽  
J. van den Bout ◽  
I. M. van Langen ◽  
...  
Keyword(s):  
At Risk ◽  
Long Qt Syndrome ◽  
Genetic Test ◽  
Test Results ◽  
Long Qt ◽  
Genetic Test Results ◽  
Qt Syndrome

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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