DEVELOPMENT OF EPOXY RESIN OR ACRYL TYPE ADHESIVE COATING METHOD FOR REDUCTION OF MACROCELL CORROSION AFTER PATCH REPAIR

2017 ◽  
Vol 20 (3) ◽  
pp. 447-456
Author(s):  
Tasturou Hatanaka ◽  
Shinichi Miyazato ◽  
Daishin Hanaoka
Keyword(s):  
Epoxy Resin ◽  
Patch Repair ◽  
Coating Method ◽  
Adhesive Coating ◽  
Macrocell Corrosion

Macrocell Corrosion Formation in Concrete Patch Repairs - A Laboratory Study

2016 ◽  
Vol 711 ◽  
pp. 68-75
Author(s):  
Choorackal A. Eldho ◽  
Ominda Nanayakkara ◽  
Jun Xia ◽  
Stephen W. Jones
Keyword(s):  
Field Application ◽  
Patch Repair ◽  
Steel Bar ◽  
Repair Materials ◽  
Steel Bars ◽  
Patch Repairs ◽  
Macrocell Current ◽  
Macrocell Corrosion ◽  
Chloride Contaminated

Corrosion of reinforcement steel bars is a major threat to the durability of concrete structures exposed to chloride contaminated environment. Patch repairing is widely practiced in affected structures to avoid further damage due to corrosion. Macrocell formation within the patch repair is identified as one main reason for the failure of patch repairs. In the present study, a group of patch repairing materials is tested for their potential to form macrocell corrosion after repaired in a chloride contaminated environment. The influence of parameters such as level of chloride contamination, type of repair materials and the area of steel bar receiving repair are presented based on macrocell current measurements. The selected repair materials for study were cement based, GGBS based and polymer based in its composition. It is found that the severity of macrocell depends on the driving potential existing between the repair and substrate concrete. The quality of substrate concrete and repair material influences the macrocell formation. The surface area of the steel bar that receives the repair also affects the macrocell current. The study will be used for the evaluation of repair materials for macrocell corrosion formation potential before their field application in a chloride contaminated environment.

scholarly journals Corrosion of concrete reinforcement and electrochemical factors in concrete patch repair

2006 ◽  
Vol 33 (6) ◽  
pp. 785-793 ◽  
Author(s):  
Jieying Zhang ◽  
Noël P Mailvaganam
Keyword(s):  
Current Knowledge ◽  
Corrosion Damage ◽  
Complex Problem ◽  
Patch Repair ◽  
Key Factors ◽  
Deterioration Mechanism ◽  
Service Exposure ◽  
Corrosion Mechanisms ◽  
Macrocell Corrosion ◽  
Concrete Reinforcement

Corrosion of concrete reinforcement at a patch repair is a complex problem, and current knowledge of its mechanism is quite limited. This review examined the correlation between two corrosion mechanisms, macrocell and microcell corrosion, from fundamental electrochemical principles. It was found that both mechanisms could play significant roles in inducing corrosion damage, contrary to the prevailing opinion that macrocell corrosion is the main deterioration mechanism in patch repair. This has practical implications that need to be considered for an effective and durable repair. A review of the studies done to date also enabled the identification of the key factors in patch repair controlling the corrosion characteristics. Corrosion could occur at different locations in the vicinity of the patch — substrate, interface, or patch area — depending on the respective electrochemical environments induced by the repair material properties and treatments, as well as the in-service exposure and mechanical loading. The review indicates that much of the needed research should focus on identification of corrosion mechanisms to effect successful patch repair in reinforced concrete structures.Key words: patch repair, substrate, corrosion, macrocell corrosion, microcell corrosion.

Investigation of Strain Sensing Capabilities of Amorphous Magnetostrictive Wires Embedded in Epoxy Resin

2011 ◽  
Vol 495 ◽  
pp. 276-279
Author(s):  
A.C. Christopoulos ◽  
I. Koulalis ◽  
G.J. Tsamasphyros ◽  
G. Kanderakis
Keyword(s):  
Composite Materials ◽  
Epoxy Resin ◽  
Structural Integrity ◽  
Ferromagnetic Material ◽  
Patch Repair ◽  
Strain Sensing ◽  
Current Sensing ◽  
High Durability ◽  
Bonded Composite ◽  
Contact Sensing

The development of fibers and adhesive systems with high durability has recently led to the creation of a new repair method of metallic structures, by the use of reinforcing patches made of composite materials. This technique is generally reported as "Composite patch repair" and provides very important advantages compared to the conventional methods of repairs. On the other hand, the technology of induction heating constitutes an innovative approach to achieve the supply of energy for the curing of resins or for the manufacturing of composite materials. In the case of resins, a ferromagnetic material must be imported into the resin, to produce the required heat. This may be achieved by importing a metallic grid in the resin. Moreover, this metallic grid, which remains inside the resin after the curing, may serve as sensor by analyzing its electrostatic properties, thus providing useful information about the structural integrity of the area (e.g. potential increase of the crack below a bonded composite repair). In this paper we present results concerning the strain sensing capabilities of amorphous magnetostrictive wires embedded in epoxy resin. The inverse magnetostrictive effect leads to a change of permeability of wires so that applied stress can change the impedance of the amorphous wires due to the skin effect with alternating current excitation. Two different types of sensing were used, contact sensing (attachment of the wire “gauge” to a sensing devise) and induction sensing (eddy current sensing probe).

A Study on B-Stage CNT / Epoxy Composite Films for Electronic Packaging Applications

2010 ◽  
Vol 654-656 ◽  
pp. 2755-2758 ◽  
Author(s):  
Kyoung Wook Paik ◽  
Seung Hun Han
Keyword(s):  
Electrical Conductivity ◽  
Epoxy Resin ◽  
Electronic Packaging ◽  
Epoxy Composite ◽  
Composite Films ◽  
Dispersion Process ◽  
Roll Coating ◽  
Film Type ◽  
Uniform Dispersion ◽  
Coating Method

Carbon nanotubes (CNTs) have remarkable mechanical strength, electrical conductivity, and thermal conductivity in spite of low density. Recently, CNT / epoxy composite have been widely investigated in terms of fabrication process and material characterizations. However, there have been few previous studies on B-stage film type CNT / epoxy composites for electronic packaging applications. B-stage film type CNT / epoxy composite films were fabricated and their properties were characterized for electronic packaging applications. The most important issue on fabrication on B-stage epoxy based films were uniform dispersion of CNTs in an epoxy resin. In this study, using optimized dispersion process, CNT / epoxy films were coated on a releasing film and subsequently dried by the comma roll coating method. Curing behavior of B-stage films, mechanical properties and electrical properties of fully cured films were characterized as a function of CNT contents. According to experimental results, CNTs lowered the curing activation energy of epoxy resin and increased electrical conductivity of epoxy resin.

Ultrastructural investigation of spontaneous pituitary gonadotroph cell adenomas in aging Sprague-Dawley rats

1983 ◽  
Vol 41 ◽  
pp. 702-703
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Epoxy Resin ◽  
Immunoelectron Microscopy ◽  
Tumor Type ◽  
Gonadal Function ◽  
Sprague Dawley ◽  
Male And Female ◽  
Reticulin Fibers ◽  
Sprague Dawley Rats

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples

1968 ◽  
Vol 26 ◽  
pp. 332-333
Author(s):  
C. F. Oster
Keyword(s):  
Biological Sciences ◽  
Epoxy Resin ◽  
Cross Sections ◽  
Biological Samples ◽  
Industrial Applications ◽  
Photographic Film ◽  
Silver Particles ◽  
Thin Sectioning ◽  
Embedding Medium

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.

Ultrastructure of the basal body apparatus in epidermal cells of a sponge larva (Aplysilla SP: Demospongiae)

1992 ◽  
Vol 50 (1) ◽  
pp. 928-929
Author(s):  
R.L. Pinto ◽  
R.M. Woollacott
Keyword(s):  
Sodium Bicarbonate ◽  
Epoxy Resin ◽  
Basal Body ◽  
Phosphate Buffer ◽  
Similar Data ◽  
Basal Apparatus ◽  
Striated Rootlet ◽  
The Common ◽  
Basal Foot ◽  
Sexually Mature

The basal body and its associated rootlet are the organelles responsible for anchoring the flagellum or cilium in the cytoplasm. Structurally, the common denominators of the basal apparatus are the basal body, a basal foot from which microtubules or microfilaments emanate, and a striated rootlet. A study of the basal apparatus from cells of the epidermis of a sponge larva was initiated to provide a comparison with similar data on adult sponges.Sexually mature colonies of Aplysillasp were collected from Keehi Lagoon Marina, Honolulu, Hawaii. Larvae were fixed in 2.5% glutaraldehyde and 0.14 M NaCl in 0.2 M Millonig’s phosphate buffer (pH 7.4). Specimens were postfixed in 1% OsO4 in 1.25% sodium bicarbonate (pH 7.2) and embedded in epoxy resin. The larva ofAplysilla sp was previously described (as Dendrilla cactus) based on live observations and SEM by Woollacott and Hadfield.

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