Evaluation of Two Corrosion Inhibitors Using Two Surface Application Methods for Reinforced Concrete Structures

Evaluation of Two Corrosion Inhibitors Using Two Surface Application Methods for Reinforced Concrete Structures
Author: Stephen R. Sharp
Publisher:
Total Pages: 38
Release: 2004
Genre: Concrete bridges
ISBN:

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This study investigated the use of penetrating corrosion inhibitors to extend the life of existing reinforced concrete bridge decks. The use of assisted (vacuum/pressure injection) and unassisted (diffusion) treatment methods and two inhibitors were evaluated. The inhibitors were FerroGard 903, from Sika Corp., and TPS-II, from Surtreat International. Testing was performed on exposure slabs with 15 lb/yd3 of NaCl in the top layer and no NaCl in the bottom layer. The slab design was a variation of the specimen design provided in ASTM G109, with each slab containing nine steel reinforcing rods instead of three. The exposure slabs had either a uniform cover over the top pieces of steel or an inclined cover over the steel. TPS-II was also evaluated on the deck of a bridge in Orange County, Virginia. The study found that when applied to the concrete surface, neither inhibitor penetrated the concrete to reach the steel reinforcement. The vacuum/pressure injection method showed promise but requires refinement. In addition, based on macro-cell measurements, a sufficient quantity of inhibitor can be injected into the concrete to reduce the charge passed.

Evaluation of Corrosion Inhibitors in Chloride-contaminated Reinforced Concrete

Evaluation of Corrosion Inhibitors in Chloride-contaminated Reinforced Concrete
Author: Roumiana Hristova
Publisher:
Total Pages: 0
Release: 1996
Genre:
ISBN:

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The report describes research to determine the effectiveness of commercial corrosion-inhibiting admixtures on the corrosion of reinforcing steel in chloride contaminated concrete. Domestic and foreign publications were reviewed to locate performance data and current practices related to the use, testing and evaluation of corrosion inhibiting admixtures. The study consisted of identification and evaluation of the currently used corrosion-inhibiting admixtures in the United States and other countries. A list of available corrosion-inhibiting admixtures were appraised. Consideration was given to performance predictability, practicality, cost, and other pertinent factors. Five-year old "lollipop" concrete speciments containing sodium nitrite and dinitrobenzoic acid as corrosion inhibitors, and comparison with control specimens were studied using linear polarization and impedance spectroscopy. All mixes had different amounts of calcium chloride added. An equivalent circuit model considering the physical characteristics of the rebar/concrete interface was used to simulate the impedance spectra. The RC parameters obtained from the impedance simulation, including maximum phase angle shift, surface impedance and capacitive responses, were utilized to characterize the surface corrosion of embedded steel and to evaluate the effect of inhibitors with chloride content. The corrosion current densities determined by impedance measurement were compared with those determined using linear polarization and good agreement between the two methods was obtained.

Corrosion of Steel in Concrete

Corrosion of Steel in Concrete
Author: Luca Bertolini
Publisher: John Wiley & Sons
Total Pages: 389
Release: 2013-02-26
Genre: Technology & Engineering
ISBN: 3527651713

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Steel-reinforced concrete is used ubiquitously as a building material due to its unique combination of the high compressive strength of concrete and the high tensile strength of steel. Therefore, reinforced concrete is an ideal composite material that is used for a wide range of applications in structural engineering such as buildings, bridges, tunnels, harbor quays, foundations, tanks and pipes. To ensure durability of these structures, however, measures must be taken to prevent, diagnose and, if necessary, repair damage to the material especially due to corrosion of the steel reinforcement. The book examines the different aspects of corrosion of steel in concrete, starting from basic and essential mechanisms of the phenomenon, moving up to practical consequences for designers, contractors and owners both for new and existing reinforced and prestressed concrete structures. It covers general aspects of corrosion and protection of reinforcement, forms of attack in the presence of carbonation and chlorides, problems of hydrogen embrittlement as well as techniques of diagnosis, monitoring and repair. This second edition updates the contents with recent findings on the different topics considered and bibliographic references, with particular attention to recent European standards. This book is a self-contained treatment for civil and construction engineers, material scientists, advanced students and architects concerned with the design and maintenance of reinforced concrete structures. Readers will benefit from the knowledge, tools, and methods needed to understand corrosion in reinforced concrete and how to prevent it or keep it within acceptable limits.

Concrete Solutions 2011

Concrete Solutions 2011
Author: Michael Grantham
Publisher: CRC Press
Total Pages: 872
Release: 2011-09-08
Genre: Technology & Engineering
ISBN: 0415616220

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The Concrete Solutions series of International Conferences on Concrete Repair began in 2003, with a conference held in St. Malo, France in association with INSA Rennes, followed by the second conference in 2006 ( with INSA again, at St. Malo, France), and the third conference in 2009 (in Padova and Venice, in association with the University of Padova). Now in 2011, the event is being held in Dresden in Germany and has brought together some 112 papers from 33 countries. Whereas electrochemical repair tended to dominate the papers in earlier years, new developments in structural strengthening with composites have been an increasingly important topic, with a quarter of the papers now focusing on this area. New techniques involving Near Surface Mounted (NSM) carbon fibre rods, strain hardening composites, and new techniques involving the well established carbon fibre and polyimide wrapping and strengthening systems are presented. Seventeen papers concentrate on case studies which are all-important in such conferences, to learn about what works (and what doesn’t work) on real structures. Thirteen papers are devoted to new developments in Non-Destructive Testing (NDT). Other topics include service life modelling, fire damage, surface protection methods and coatings, patch repair, general repair techniques and whole life costing. This book is essential reading for anyone engaged in the concrete repair field, from engineers, to academics and students and also to clients, who, as the end user, are ultimately responsible for funding these projects and making those difficult decisions about which system or method to use.

Corrosion Inhibitors for Steel in Concrete

Corrosion Inhibitors for Steel in Concrete
Author: Bernhard Elsener
Publisher: CRC Press
Total Pages: 84
Release: 2001
Genre: Business & Economics
ISBN:

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The use of inhibitors for rehabilitation of reinforced concrete structures is a new field of application and this new volume provides a State of the Art Report on this subject. Corrosion of steel in concrete is one of the major problems for infrastructure such as bridges, tunnels, housing etc. since it leads to spalling of the concrete and loss in cross section of the steel that may cause structural and safety problems. The steel in concrete generally resists corrosion as a result of a passive layer that develops on the metal surface in the alkaline environment of the concrete. Corrosion can occur if these conditions are disturbed, for example, in the presence of chlorides or with carbonation of concrete. Traditional repair methods consist in removing the deteriorated concrete and replacing it but these can be laborious, noisy and very costly. To avoid these disadvantages new methods have been developed in recent years. These include electrochemical procedures and, increasingly, the use of inhibitors. The use of inhibitors for rehabilitation of reinforced concrete structures is a new field of application and this new volume provides a State of the Art Report on this subject.The report, under the editorship of Prof. Bernhard Elsener, was prepared by a Task Group of the EFC Working Party on Corrosion of Reinforcement in Concrete. In a literature review it describes inorganic and organic chemicals that have been proposed and examined as well as the commercial corrosion inhibitors that are available on the market. Protection mechanism and possible effects of inhibitors on concrete properties are described. Practical experience with inhibitors for steel in concrete and the long term effectiveness are considered. The various test methods for evaluating the behaviour of the inhibitors are described and critically assessed. In a rapidly evolving field this State of the Art Report, based mainly on independent not commercial literature, will be of value to corrosion engineers and civil engineers concerned with maintenance and repair of reinforced concrete structures.

Performance Evaluation of Corrosion Inhibitors and Galvanized Steel in Concrete Exposure Specimens

Performance Evaluation of Corrosion Inhibitors and Galvanized Steel in Concrete Exposure Specimens
Author: Jerzy Zemajtis
Publisher:
Total Pages: 80
Release: 1999
Genre: Concrete bridges
ISBN:

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Corrosion inhibitor admixtures (CIA) and galvanized reinforcing steel (GS) are used for the corrosion protection for reinforced concrete bridges. The results of a 3.5-year evaluation of exposure specimens containing CIA from three different manufacturers and GS are presented. The specimens were built to simulate four exposure conditions typical for concrete bridges located in the coastal region or inland where deicing salts are used. The exposure conditions were Horizontal, Vertical, Tidal, and Immersed Zones. The specimens were kept inside the laboratory and were exposed to weekly ponding cycles of 6% sodium chloride solution by weight. The methods used to assess the condition of the specimens included chloride concentration measurements, corrosion potentials, and corrosion rates. Additionally, visual observations were performed for identification of rust stains and cracking on concrete surfaces. The results of chloride testing indicate that the amount of chlorides present at the bar level is more than sufficient to initiate corrosion. Chloride and rapid permeability data indicate no significant difference either in a rate of chloride ingress or in the diffusion coefficients for concretes with and without CIA. Corrosion potentials were the most negative for the Bare Steel (BS) specimen prepared with the Armatec 2000 corrosion inhibitor and generally indicated a 90% probability of active corrosion. Corrosion potentials were similar for the two BS control specimens and the BS specimen prepared with Rheocrete 222 and generally indicated an uncertain probability of corrosion. Corrosion potentials were the least negative for the BS specimen prepared with DCI-S corrosion inhibitor and generally indicated a 90% probability of no corrosion. Rate of corrosion measurements were the highest for the BS control specimens and the one prepared with A2000 and the most recent data suggest corrosion damage in 2 to 10 years. Although early rate of corrosion measurements were higher or about the same as for BS control specimens, recent measurements were slightly lower for the specimen prepared with Rheocrete 222 and suggest corrosion damage in 10 to 15 years. Rate of corrosion measurements were consistently the lowest for the BS specimens prepared with DCI-S and indicate corrosion damage is expected in 10 to 15 years. The corrosion potential and rate of corrosion data indicate that DCI-S is the only CIA evaluated that clearly provides some level of corrosion protection. A direct comparison of the GS specimens to the BS specimens is not possible because the measured potential refers to the zinc oxide and not to the steel. Nevertheless, the potential data agree with the chloride and permeability data, as well as with the visual observations, and indicate the damaging effect of a high concentration of chloride ions on the GS. At low and moderate chloride exposures, however, GS does provide corrosion protection. Recommendations are to continue monitoring until sufficient cracking has occurred in all specimens to provide for making a better estimate of the service lives of CIA and GS used in the construction of concrete bridge components in Virginia. The specimens with CIA and one control (continuous reinforcement in the legs) should be taken to the Hampton Road North Tunnel Island and placed in the brackish water to a depth of the Immersed Zone at low tide for further exposure to chloride. The specimens with GS and the other control (non-continuous reinforcement in the legs) should remain in an outdoor exposure in Southwest Virginia like the Civil Engineering Materials Research Laboratory in Blacksburg, Virginia.

Long-term Performance of Corrosion Inhibitors Used in Repair of Reinforced Concrete Bridge Components

Long-term Performance of Corrosion Inhibitors Used in Repair of Reinforced Concrete Bridge Components
Author: Moavin Islam
Publisher: DIANE Publishing
Total Pages: 58
Release: 2003
Genre: Concrete bridges
ISBN: 1428995242

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The primary objective of the project was to determine the effectiveness of cathodic protection, electrochemical chloride extraction, and corrosion-inhibitor treatment systems installed during the SHRP effort through the long-term evaluation of 32 field test sites and a number of laboratory concrete slab specimens. The FHWA program required monitoring the long-term performance of corrosion inhibitor treatments on selected components of four bridges that were treated and evaluated under SHRP C-103. Three evaluations over a period of 5 years were conducted on structures located in Minnesota, New York and Pennsylvania, and two evaluations were conducted on a structure in Washington State. An analysis of the results concluded that neither of the corrosion inhibitors evaluated in this study, using the specified repairs and exposed to the specific environments, provided any corrosion-inhibiting benefit. Shrinkage cracking plagued repairs at all test sites except for the Washington site.