PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

'Macrocells' influence corrosion rate of submerged marine concrete structures

2013-12-18
(Press-News.org) Contact information: Alysa Reich
alysa.reich@nace.org
281-228-6280
NACE International
'Macrocells' influence corrosion rate of submerged marine concrete structures

Using numerical modeling, an Italian research team has discovered the role 'macrocells' play in the corrosion of hollow submerged marine concrete structures such as tunnels and parking structures.

In marine environments, chloride-induced corrosion of steel can quickly take a toll on hollow submerged structures such as tunnels or parking structures by degrading their concrete and reinforced steel bars. This is a serious problem, given the high cost associated with building these structures and the fact that regular maintenance and restoration activities can prove quite challenging.

A research team in Italy used numerical modeling to explore chloride-induced corrosion and its impact on hollow submerged marine concrete structures. They describe their findings, including the role of the "macrocell" phenomenon, in a paper published in CORROSION journal.

"Chloride-induced corrosion occurs within the presence of chloride, which is commonly dissolved in seawater, and oxygen on a steel surface," explains Federica Lollini, assistant professor, Department of Chemistry, Materials, and Chemical Engineering, Politecnico di Milano. "This means that reinforced concrete structures exposed to the tidal zone—in which wetting and drying cycles bring chloride and oxygen into contact with steel surfaces—are more prone to chloride-induced corrosion than those completely submerged in seawater, in which oxygen concentrations are low."

For the type of hollow submerged marine structures the researchers focused on, chlorides contaminate only the external side of the wall in contact with seawater, while oxygen is present only in the internal wall in contact with the atmosphere.

"Under these conditions, a phenomenon called 'macrocell' can occur," says Lollini. "Macrocells involve the circulation of an electric current between the reinforcing bars in the external side of the wall and those in the internal one, and it can lead to chloride-induced corrosion in submerged structures."

While macrocells may, in theory, greatly influence the development of corrosion in these types of reinforced concrete structures, their effects tend to be neglected by designers due to a lack of knowledge about this phenomenon, according to Lollini and colleagues.

So they decided to zero in on the effects of macrocells through numerical models, which are able to simulate the behavior of real structures, as long as the appropriate electrochemical parameters are used to describe the phenomenon. Their models confirmed that the effects of macrocells shouldn't be neglected.

"Macrocells may trigger chloride-induced corrosion and increase its speed, which means it may significantly reduce the duration of the service life of submerged hollowed structures," Lollini says.

These findings may ultimately lead to the development of appropriate design criteria for hollow reinforced concrete structures submerged in seawater. "Our numerical models can serve as the starting point for further simulations aimed at exploring the effectiveness of electrochemical techniques that can be applied to submerged structures to prevent the initiation of corrosion or to lower the steel corrosion rate if it's already begun," notes Lollini.



INFORMATION:

Image caption: This schematic shows the effects of a macrocell between a corroding reinforced steel bar (black dot) and non-corroding bars (white dots). The arrows depict the electric current circulating between the bars, while the colors show the variation of the electrochemical potential in the concrete wall (blue for high potential or red for low potential).

More Information: The paper, "Numerical Modeling of Initiation and Propagation of Corrosion in Hollow Submerged Marine Concrete Structures," written by A. Della Pergola, F. Lollini, E. Redaelli, and L. Bertolini, appears in NACE International's journal, CORROSION, Dec. 2013, Vol. 69, No. 12, pp. 1158-1170. See: http://dx.doi.org/10.5006/0916

About NACE International: Founded in 1943, NACE International, The Corrosion Society, serves 30,000 members in 130 countries. Based in Houston, Texas, with offices in the U.S., China, Malaysia, and Saudi Arabia, the organization reaches all industries impacted by corrosion and offers the most specified technical training and certification programs, conferences, industry standards, reports, publications, and software to prevent and mitigate corrosion. NACE International provides members with career and business building resources, government relations and public awareness support, and research and education to support the pursuit of global corrosion control solutions.

CORROSION is a technical research journal devoted to furthering the knowledge of corrosion science and engineering. The technical articles selected for publication in CORROSION provide a permanent record of the latest progress in the science and technology of corrosion control. The journal is directed at scientists and engineers concerned with the phenomena of corrosion processes and the protection of materials in corrosive environments. For more information, please visit http://corrosionjournal.org.



ELSE PRESS RELEASES FROM THIS DATE:

Oil- and metal-munching microbes dominate deep sandstone formations

2013-12-18
Oil- and metal-munching microbes dominate deep sandstone formations Findings useful to hydrocarbon extraction and carbon sequestration efforts CHAMPAIGN, Ill. — Halomonas are a hardy breed of bacteria. They can withstand heat, high salinity, low oxygen, ...

Scientists reduce protein crystal damage, improve pharmaceutical development

2013-12-18
Scientists reduce protein crystal damage, improve pharmaceutical development 'Submicrometer line focusing' identified as standard for crystallophhy New recommendations for using X-rays promise to speed investigations aimed at understanding the structure and function ...

UT Austin researchers design first battery-powered invisibility cloak

2013-12-18
UT Austin researchers design first battery-powered invisibility cloak Researchers design an invisibility cloak attached to a power source Researchers at The University of Texas at Austin have proposed the first design of a cloaking device that uses an external source ...

Non-specialist psychosocial interventions for children with autism spectrum disorders

2013-12-18
Non-specialist psychosocial interventions for children with autism spectrum disorders Many children with intellectual disability or lower functioning autism spectrum disorders, particularly those in low and middle income countries, do not receive psychosocial treatment ...

Will stem cell therapy help cure spinal cord injury?

2013-12-18
Will stem cell therapy help cure spinal cord injury? A systematic survey of the scientific literature shows that stem cell therapy can have a statistically significant impact on animal models of spinal cord injury, and points the way for future studies. Spinal cord ...

Much room for improvement in access to preventive dental care in the USA

2013-12-18
Much room for improvement in access to preventive dental care in the USA The uptake rate of preventative dental care increased over a ten-year period in the United States, but there remains a large disparity among ethnic groups, reports one of the largest and most comprehensive studies ...

Medical communication companies receive substantial support from drug and device companies

2013-12-18
Medical communication companies receive substantial support from drug and device companies Eighteen medical communication companies (MCCs) received about $100 million from 13 pharmaceutical and one device company that released data in 2010, and all or most of ...

Study assesses amount, patterns of sedentary behavior of older women

2013-12-18
Study assesses amount, patterns of sedentary behavior of older women Among 7,000 older women who wore an accelerometer to measure their movement, about two-thirds of their waking time was spent in sedentary behavior, most of which occurred in periods of less than ...

Nonsurgical treatment of periodontitis for persons with diabetes does not improve glycemic control

2013-12-18
Nonsurgical treatment of periodontitis for persons with diabetes does not improve glycemic control For persons with type 2 diabetes and chronic periodontitis, nonsurgical periodontal treatment did not result in improved glycemic control, according to ...

Experts discover whether it's better to be right or be happy

2013-12-18
Experts discover whether it's better to be right or be happy Researchers shed light on a frequent cause of marital discord Doctors see many couples who lead unnecessarily stressful lives by wanting to be right rather than happy. But is it better ...

LAST 30 PRESS RELEASES:

Exercise as an anti-ageing intervention to avoid detrimental impact of mental fatigue

UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’

New guidelines aim to improve cystic fibrosis screening

Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas

Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition

CCNY physicists uncover electronic interactions mediated via spin waves

Researchers’ 3D-printing formula may transform future of foam

Nurture more important than nature for robotic hand

Drug-delivering aptamers target leukemia stem cells for one-two knockout punch

New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed

New sea grant report helps great lakes fish farmers navigate aquaculture regulations

Strain “trick” improves perovskite solar cells’ efficiency

How GPS helps older drivers stay on the roads

Estrogen and progesterone stimulate the body to make opioids

Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation

Machine learning helps construct an evolutionary timeline of bacteria

Cellular regulator of mRNA vaccine revealed... offering new therapeutic options

Animal behavioral diversity at risk in the face of declining biodiversity

Finding their way: GPS ignites independence in older adult drivers

Antibiotic resistance among key bacterial species plateaus over time

‘Some insects are declining but what’s happening to the other 99%?’

Powerful new software platform could reshape biomedical research by making data analysis more accessible

Revealing capillaries and cells in living organs with ultrasound

American College of Physicians awards $260,000 in grants to address equity challenges in obesity care

Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential

Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research

Solar cells made of moon dust could power future space exploration

Deporting immigrants may further shrink the health care workforce

Border region emergency medical services in migrant emergency care

Resident physician intentions regarding unionization

[Press-News.org] 'Macrocells' influence corrosion rate of submerged marine concrete structures