Modeling of Bonding for Epoxy Resins between Steel Rebar and Concrete at Elevated Temperatures

2017 ◽  
Vol 109 (5) ◽  
pp. 3333-3340
Author(s):  
Thanyawat Pothisiri
Keyword(s):  
Epoxy Resins ◽  
Elevated Temperatures ◽  
Steel Rebar

Experimental Investigation of Adhesive Bonding for Post‐installed Rebars into Concrete at High Temperatures

2019 ◽  
Author(s):  
Thanyawat Pothisiri ◽  
Pitcha Jongvivatsakul ◽  
Vanichapoom Nantavong
Keyword(s):  
Experimental Investigation ◽  
High Temperatures ◽  
Mechanical Behaviour ◽  
Epoxy Resins ◽  
Adhesive Bonding ◽  
Elevated Temperatures ◽  
Adhesive Bond ◽  
Steel Rebar ◽  
Pull Out ◽  
Embedment Length

<p>The use of post‐installed rebars into existing reinforced concrete structures bonded with epoxy resins was constantly increasing due to the advantage of equivalent or even higher bearing capacities at service temperature, compared with conventional cast‐in‐place rebars. Previous studies have examined the effects of different parameters on the mechanical properties of bonded post‐installed rebars at normal temperature. These studies showed that, for rebar diameter equal to 10 mm, the load bearing capacity increases linearly with the embedment length up to 75 mm. However, upon exposure to high temperatures, the glass transition of epoxy resins may occur and affect the mechanical behaviour of the adhesive bond. Studying the mechanical behaviour of an adhesive anchor at high temperatures is therefore necessary. An experimental investigation is conducted herein to examine the characteristics of the adhesive bonding stress between steel rebar and concrete interface at elevated temperatures using a series of pull‐out tests with varying rebar diameters and embedment lengths.</p>

scholarly journals Strengthening epoxy adhesives at elevated temperatures based on dynamic disulfide bonds

2020 ◽  
Vol 1 (9) ◽  
pp. 3182-3188
Author(s):  
Hsing-Ying Tsai ◽  
Yasuyuki Nakamura ◽  
Takehiro Fujita ◽  
Masanobu Naito
Keyword(s):  
Glass Transition ◽  
Disulfide Bonds ◽  
Epoxy Resins ◽  
Elevated Temperatures ◽  
Adhesive Properties ◽  
Epoxy Adhesives ◽  
Transition Points ◽  
Increasing Temperature

Epoxy resins incorporating aromatic disulfide bonds demonstrated improved adhesive properties with increasing temperature below their glass transition points.

Performance of MMFX Steel Rebar at Elevated Temperatures

2020 ◽  
Vol 146 (11) ◽  
pp. 04020126
Author(s):  
Farid Abed ◽  
Akrum Abdul-Latif ◽  
George Z. Voyiadjis
Keyword(s):  
Elevated Temperatures ◽  
Steel Rebar

scholarly journals Bond Behavior between Steel Rebar and RCA Concrete after Exposure to Elevated Temperatures

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Wanjie Zou ◽  
Jiongfeng Liang ◽  
Dawei Liu ◽  
Guangwu Zhang
Keyword(s):  
Bond Strength ◽  
Elevated Temperatures ◽  
Coarse Aggregate ◽  
Test Results ◽  
Modified Model ◽  
Bond Slip ◽  
Bond Behavior ◽  
Steel Rebar ◽  
Exposure Temperature ◽  
Increasing Temperature

To explore the bond behavior between steel rebar and recycled coarse aggregate (RCA) concrete after exposure to elevated temperatures, an experimental study was carried out. The results demonstrated that the bond strength of RCA concrete pullout specimens decreased greatly with increasing temperature. As the exposure temperature elevated, the slope of the ascending portion of the bond-slip curves gradually declined, and the descending portion of the curves tended to flatten. A modified model was developed to predict the bond strength between RCA concrete and steel rebar after exposure to elevated temperature, and the predicted results showed a very good fit in the experimental test results. Besides, the proposed bond-slip relations for steel rebar in RCA concrete after elevated temperatures showed satisfactory agreement with test results.

Modeling of bonding between steel rebar and concrete at elevated temperatures

2012 ◽  
Vol 27 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Thanyawat Pothisiri ◽  
Pattamad Panedpojaman
Keyword(s):  
Elevated Temperatures ◽  
Steel Rebar

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

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