Accelerated testing for chloride threshold of reinforcing steel in concrete

Testing for the chloride threshold (also called critical chloride content) for corrosion initiation of steel in concrete has been found difficult and, at best, time consuming. Nevertheless, the chloride threshold is an important parameter in service life design of new structures and for evaluation of the remaining service life of existing...

A proposal for determining the remaining time to chloride induced corrosion initiation of existing reinforced concrete structures

Asset managers would benefit from knowing when to expect corrosion initiation in a particular reinforced concrete structure. However, accepted approaches to test existing structures for the remaining time to corrosion initiation are lacking. This paper proposes such an approach, based on experience in the field and additional considerations....

Chloride transport testing of blast furnace slag cement for durable concrete structires in Norway: From 2 days to one year age

Blast furnace slag cement (BFSC) has been used in reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. Experience is good and long service lives can be obtained. In Norway experience with BFSC is scarce. In The Netherlands, a high resistance against chloride penetration and a high electrical...

Propagation of pitting corrosion of steel in concrete: Conceptual models for local cross section loss

Where exposed to an aggressive environment, concrete structures will develop reinforcement corrosion at some point in their life. Chloride ions from de-icing salt or sea water induce pitting corrosion. Local cross section reduction may occur relatively quickly and expansion due to corrosion products precipitating may crack and spall concrete...

Anwendung von kathodischen Korrosionsschutzmaßnahmen bei 30 Spannbetonbrücken in den Niederlanden

Die oberste niederländische Straßen- und Wasserbaubehörde (Rijkswaterstaat) hat im Hinblick auf die langfristige Instandhaltung ihrer Infrastruktureinrichtungen über 1500 Endverankerungsbereiche von Spannbetonbrückenträgern instandgesetzt und einer kathodischen Korrosionsschutzbehandlung (KKS) unterzogen. Die Endbereiche wiesen mäßige bis starke...

Assessment of cracks in reinforced concrete by means of electrical resistance and image analysis

The durability of cracked reinforced concrete is a serious concern in the construction industry. Cracks represent fast routes for chloride penetration, which can result in reinforcement corrosion. Bending or tapered cracks have the characteristic of being wider at the surface and becoming narrower towards the reinforcement. In reinforced...

Innovation based on tradition: Blast furnace slag cement for durable concrete structures in Norway

road environment in The Netherlands for nearly a century. The experience is good and structures with long service lives can be obtained, as has been shown by several field studies. This is caused by a high resistance against chloride penetration and a high electrical resistivity, demonstrated both in the field and in the laboratory. Due to the...

Early stage beneficial effects of cathodic protection in concrete structures

Over the last 25 years, cathodic protection (CP) of reinforced concrete structures suffering from chloride induced reinforcement corrosion has shown to be successful and durable. CP current causes steel polarisation, electrochemical reactions and ion transport in the concrete. CP systems are designed based on experience, which results in...

Critical chloride content for reinforced concrete and its relationship to concrete resistivity

The critical chloride content for initiation of reinforcement corrosion is an essential element in service life design and modelling of concrete structures.The critical content is laden with questions regarding its definition, experimental assessment and practical aspects. It should be addressed by a statistical approach. The paper discusses...

Use of advanced corrosion monitoring for risk based management of concrete structures

Reinforced concrete is a cost effective material used widely in our infrastructure. The durable combination of steel and concrete provides safety and serviceability. Normally, the physics and chemistry of concrete protects reinforcing steel against corrosion. Over time this protection can be lost due to aggressiveness from the environment, for...

Durability of marine concrete structures - field investigations and modelling

This article presents a series of investigations on six concrete structures along the North Sea coast in The Netherlands. They had ages between 18 and 41 years and most of them were made using Blast Furnace Slag cement. Visual inspections showed corrosion damage in only one structure, related to relatively low cover depths. All structures showed...

Prevention of reinforcement corrosion by hydrophobic treatment of concrete

Corrosion of reinforcement in concrete bridge decks may occur due to penetration of de-icing salts, even in the presence of an asphalt overlay. This paper reports a laboratory study into additional protection of concrete by hydrophobic treatment. It was found that hydrophobic treatment strongly reduces chloride ingress, both during semi...

Test methods for on site measurement of resistivity of concrete. A RILEM TC-154 Technical Recommendation

This paper describes methods to assess concrete resistivity on site for various purposes related to corrosion and protection of reinforcement. It is based on a first draft of a RILEM Technical Recommendation. The electrical resistivity of concrete can be related to the two processes involved in corrosion of reinforcement: initiation (chloride...

Cathodic protection of concrete ground floor elements with mixed in chloride

Corrosion of reinforcement in precast concrete ground floor elements containing mixed in chloride can cause considerable damage. This is a major problem in the Netherlands concerning a large number of privately owned houses. Conventional concrete repair is not acceptable because it does not provide sufficient durable safety. Cathodic protection...

Corrosion protection of reinforcement by hydrophobic treatment of concrete

Penetration of de-icing salts into concrete bridge decks may cause corrosion of reinforcement. Hydrophobic treatment of concrete was studied as additional protection. It was shown that hydrophobic treatment strongly reduces chloride ingress, during semi-permanent contact and in wetting/drying situations. The protection remains effective for at...

Experimental study of cathodic protection of concrete from a 30 year old bridge

An experimental study of cathodic protection (CP) was carried out with a conductive primer anode applied to specimens from a concrete bridge. The bridge was demolished after 30 years of service due to severe delaminations and reinforcement corrosion. Four specimens of approximately 1 m2 each were made and characterised by steel potential,...

The influence of blast furnace slag, fly ash and silica fume on corrosion of reinforced concrete in marine environment

Chloride penetration from sea water may cause corrosion of reinforcement in concrete structures. Adding reactive inorganic materials such as blast furnace slag, fly ash or silica fume to the cement matrix improves the resistance against chloride penetration as compared to Portland cement concrete. A relatively simple laboratory procedure was...