scholarly journals Laboratory Assessment of Select Methods of Corrosion Control and Repair in Reinforced Concrete Bridges

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Matthew D. Pritzl ◽  
Habib Tabatabai ◽  
Al Ghorbanpoor
Keyword(s):  
Reinforced Concrete ◽  
Surface Coating ◽  
Concrete Bridges ◽  
Patch Repair ◽  
Chloride Ingress ◽  
Corrosion Control ◽  
Laboratory Assessment ◽  
Accelerated Corrosion ◽  
Deicing Salts ◽  
Patch Repairs

Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC) procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered mixed-in chlorides to represent chloride contamination due to deicing salts. All specimens were exposed to accelerated corrosion testing for three months, subjected to patch repairs with various treatments, and further subjected to additional three months of exposure to accelerated corrosion. The use of thermal sprayed zinc, galvanic embedded anodes, epoxy/polyurethane coating, acrylic coating, and an epoxy patch repair material was evaluated individually or in combination. The specimens were assessed with respect to corrosion currents (estimated mass loss), chloride ingress, surface rust staining, and corrosion of the reinforcing steel observed after dissection. Results indicated that when used in patch repair applications, the embedded galvanic anode with top surface coating, galvanic thermal sprayed zinc, and galvanic thermal sprayed zinc with surface coating were more effective in controlling corrosion than the other treatments tested.

scholarly journals Assessment of corrosion-induced bond deterioration in reinforced concrete: towards a splitting crack-based approach

2021 ◽  
Author(s):  
Michele Win Tai Mak ◽  
Janet M. Lees
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Steel Corrosion ◽  
Concrete Bridges ◽  
Reinforcing Bars ◽  
Accelerated Corrosion ◽  
General Validity ◽  
Safety Risks ◽  
Infrastructure Network ◽  
Residual Capacity

<p>Reinforced concrete structures are subjected to several sources of deterioration that can reduce their load-resisting capacity over time. This has significant consequences for the management of infrastructure, leading to high costs of maintenance, repair, strengthening and premature decommissioning. Assessing the residual capacity of structures is challenging but paramount to manage the infrastructure network effectively. Corrosion of the internal steel reinforcement is among the main causes of deterioration in reinforced concrete bridges. The subsequent reduction in steel-to-concrete bond strength is difficult to evaluate with accuracy. There is no unified theory of general validity. Most existing models adopt measures of the level of corrosion as the key parameter to evaluate the bond reduction. In this paper, a different approach is investigated. Corrosion-induced splitting crack widths are used as the fundamental indicator of bond strength reduction, irrespective of the associated degree of steel corrosion. Available experimental results on deformed steel bars embedded in concrete subjected to either natural or accelerated corrosion, with or without transverse reinforcement, are analysed and compared with a different perspective. The analysis indicates that this new splitting crack-based approach can lead to more accurate predictions. This contributes to a better understanding of the fundamental principles underlying bond of corroded reinforcing bars. Enhanced assessment strategies can lead to a reduction of the safety risks, maintenance costs and environmental footprint of the infrastructure network.</p>

Accelerated corrosion investigation of axially loaded reinforced concrete elements

2014 ◽  
Vol 61 (4) ◽  
pp. 215-223 ◽  
Author(s):  
Christos Zeris ◽  
George Batis ◽  
Vassilios Mouloudakis ◽  
John Marakis
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Load Capacity ◽  
Axial Loading ◽  
Load Level ◽  
Concrete Cover ◽  
Chloride Ingress ◽  
Reinforced Concrete Column ◽  
Accelerated Corrosion ◽  
Content Type

Purpose – This paper aims to present results of an experimental investigation on a series of scaled reinforced concrete column elements which were subjected to chloride exposure under accelerated conditions under a concurrent service axial load, over a period. In the presence of an axial load, directed microcracks of increasing density and width are introduced in the concrete mass, depending on the axial load level. Such cracks are believed to enhance the intrusion rate of chlorides in the concrete, relative to what is obtained in the normally performed unloaded specimen tests. Design/methodology/approach – Eighteen column specimens were tested over two chloride exposure periods, of duration up to a maximum of six months. Three different service axial load levels were considered, namely, none, 22 per cent and 43 per cent of the normalized axial load capacity of the columns. Findings – The results indicate that the specimens loaded to the higher axial load, which closely resembles actual service situation of such type of elements, exhibited up to ten times faster rates of induced current flow under a constant applied voltage of 500 mV, compared to the unloaded and less loaded specimens. Practical implications – It is proven that the presence of axial load influences the rate of chloride ingress in columns and, therefore, should be taken into account in estimating the concrete cover of such elements in durability design. Originality/value – The influence of axial loading on corrosion rate has not been considered in published experimental and analytical studies of chloride ingression. These studies have typically so far considered the accelerated corrosion of unloaded column specimens.

scholarly journals Value of Information (VoI) for the Chloride Content in Reinforced Concrete Bridges

2020 ◽  
Vol 10 (2) ◽  
pp. 567
Author(s):  
Ivan Zambon ◽  
Monica Patricia Santamaria Ariza ◽  
José Campos e Matos ◽  
Alfred Strauss
Keyword(s):  
Reinforced Concrete ◽  
Minimum Cost ◽  
Cost Effective ◽  
Chloride Content ◽  
Concrete Bridges ◽  
Chloride Ingress ◽  
Maximum Cost ◽  
Initiation Phase ◽  
Reinforced Concrete Bridges ◽  
The Cost

The corrosion of reinforcement caused by chloride ingress significantly reduces the length of the service life of reinforced concrete bridges. Therefore, the condition of bridges is periodically inspected by specially trained engineers regarding the possible occurrence of reinforcement corrosion. Their main goal is to ensure that the structure can resist mechanical and environmental loads and offer a satisfactory level of safety and serviceability. In the course of assessment, measuring the chloride content, through which corrosion could be anticipated and prevented, presents a possible alternative to visual inspections and corrosion tests that can only indicate already existing corrosion. It is hard to determine the cost-effectiveness and actual value of chloride content measurements in a simple and straightforward way. Thus, the main aim of the paper was to study the value of newly gained information, which is obtained when a chloride content in reinforced concrete bridges is measured. This value was here analyzed through the pre-posterior analysis of the cost of measurement and repair, taking into account different types of exposure and material properties for a general case. The research focus was set on the initiation phase in which there are no visible damages. A relative comparison of costs is presented, where the cost of possible reactive/proactive repair was compared with the maximum cost of measurement, while the measurement is still cost effective. The analysis showed a high influence of the initial probability of depassivation on the maximum cost of the cost-effective measurement, as well as a nonreciprocal relation of the minimum cost of cost-effective reactive repair with the measurement accuracy.

The Effect of Type and Height of Piers on the Seismic Behavior of Reinforced Concrete Bridges

2019 ◽  
Vol 41 ◽  
pp. 79-87 ◽  
Author(s):  
Mohamed Cherif Djemai ◽  
Mahmoud Bensaibi ◽  
Fatma Zohra Halfaya
Keyword(s):  
Reinforced Concrete ◽  
Structural Parameters ◽  
Strong Motion ◽  
Concrete Bridges ◽  
Geometrical Parameters ◽  
Girder Bridges ◽  
Building Research Institute ◽  
Reinforced Concrete Bridges ◽  
Dynamic Analyses ◽  
Strong Motion Database

Bridges are commonly used lifelines; they play an important role in the economic activity of a city or a region and their role can be crucial in a case of a seismic event since they allow the arrival of the first aid. Reinforced concrete (RC) bridges are worldwide used type view their durability, flexibility and economical cost. In fact, their behavior under seismic loading was the aim of various studies. In the present study the effect of two structural parameters i.e. the height and the type of piers of reinforced concrete bridges on seismic response is investigated. For that reason, different multi-span continuous girder bridges models with various geometrical parameters are considered. Then, non-linear dynamic analyses are performed based on two types of piers which are: multiple columns bent and wall piers with varying heights. In this approach, a serie of 40 ground motions records varying from weak to strong events selected from Building Research Institute (BRI) strong motion database are used including uncertainty in the soil and seismic characteristics. Modelling results put most emphasis on the modal periods and responses of the top pier displacements, they show the influence of the considered parameters on the behavior of such structures and their impact on the strength of reinforced concrete bridges.

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