scholarly journals Impregnation technique provides corrosion protection to grouted post-tensioning tendons

2015 ◽  
pp. 1085-1092 ◽  
2018 ◽  
Vol 199 ◽  
pp. 05008
Author(s):  
David Whitmore ◽  
Ivan Lasa

Thousands of bridge structures rely on grouted post-tensioning (PT) tendons. Problems with grouting techniques and grout materials have resulted in bridges with grout voids, chloride contaminated grout and soft grout. These problems have promoted corrosion and failure of post-tension tendons, some within 6 to 17 years of service. The Florida Department of Transportation (FDOT) has spent more than $55 million (USD) repairing 11 post-tensioned bridges to date. A cost-effective corrosion mitigation technique has been developed to minimize the corrosion of PT tendons and extend the service life of bridges which have grouting issues. This paper describes the development and implementation of this technique on grouted PT bridges.


Author(s):  
K. Chien ◽  
R.C. Heusser ◽  
M.L. Jones ◽  
R.L. Van de Velde

Silver impregnation techniques have been used for the demonstration of the complex carbohydrates in electron microscopy. However, the silver stains were believed to be technically sensitive and time consumming to perform. Currently, due to the need to more specifically evaluate immune complex for localization in certain renal diseases, a simplified procedure in conjunction with the use of the microwave has been developed and applied to renal and other biopsies. The procedure is as follows:Preparation of silver methenamine solution:1. 15ml graduated, clear polystyrene centrifuge tube (Falcon, No. 2099) was rinsed once with distilled water.2. 3% hexamethylene tetramine (methenamine) was added into the centrifuge tube to the 6ml mark.3. 3% silver nitrate was added slowly to the methenamine to the 7ml mark while agitating. (Solution will instantly turn milky in color and then clear rapidly by mixing. No precipitate should be formed).4. 2% sodium borate was added to the solution to the 8ml mark, mixed and centrifuged before use.


2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-861-Pr3-867 ◽  
Author(s):  
S. M. Zemskova ◽  
J. A. Haynes ◽  
K. M. Cooley

2020 ◽  
Vol 117 (6) ◽  
pp. 610
Author(s):  
Nadia Hammouda ◽  
Kamel Belmokre

Organic coatings are widely employed in the corrosion protection of most metal surfaces, particularly steel. They provide a barrier against corrosive species present in the environment, due to their high resistance to oxygen, water and ions transport. This study focuses on the evaluation of corrosion protection performance of epoxy paint on the carbon steel surface in chloride environment (3% NaCl) by Electrochemical Impedance Spectroscopy (EIS). The electrochemical behavior of painted surface was estimated by EIS parameters that contained paint film resistance, paint film capacitance and double layer capacitance. On the basis of calculation using EIS spectrums it was observed that pore resistance (Rpore) decreased with the appearance of doubled layer capacitance (Cdl) due to the electrolyte penetration through the film. This was further confirmed by the decrease of diffusion resistance (Rd) which was also the indicator of the deterioration of paint film protectiveness. Microscopic analyses have shown that oxidation dominates the corroded surfaces.


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