Thursday 21 June 2018

Conductive paint as ‘sensing skin’ for concrete structures

, August 21, 2014

A new ‘sensing skin’ technology has been developed by researchers, which could be an early warning system for concrete structures to allow authorities to respond to concrete damage, said a report.

The ‘skin’ is an electrically conductive coat of paint that can be applied to new or existing structures, said the Global Construction Review report.

The paint can incorporate any number of conductive materials, such as copper, making it relatively inexpensive, said the research team from North Carolina State University and the University of Eastern Finland, it said.

“The sensing skin could be used for a wide range of structures, but the impetus for the work was to help ensure the integrity of critical infrastructure such as nuclear waste storage facilities,” Dr Mohammad Pour-Ghaz, an assistant professor of civil, construction and environmental engineering at North Carolina State and co-author of a paper describing the work, was quoted as saying.

“The idea is to identify problems quickly so that they can be addressed before they become big problems and ñ in the case of some critical infrastructure, so that public safety measures can be implemented,” Pour-Ghaz said.

The paper was published in June in the journal ‘Smart Materials and Structures.’ It describes how electrodes are applied around the perimeter of a structure.

The ‘sensing skin’ is then painted onto the structure, over the electrodes, after which a computer programme will run a small current between two of the electrodes at a time, cycling through a number of possible electrode combinations.

Every time the current runs between two electrodes, a computer will monitor and record the electrical potential at all of the electrodes on the structure. This data will then be used to calculate the sensing skin’s spatially distributed electrical conductivity. If its conductivity decreases, that means the structure has cracked or been otherwise damaged.

The researchers have developed a suite of algorithms that will allow them to both register damage and to determine where the damage has taken place.

“Determining the location of the damage based on the measured electrode potentials is a challenging mathematical problem,” co-author Dr Aku Seppnen, an academy research fellow in the Department of Applied Physics at the University of Eastern Finland, was quoted as saying.

“We had to develop new computational methods to more reliably determine where the damage is. Ultimately, I think our work represents an advance over previous algorithms in terms of accuracy.”

The researchers demonstrated the effectiveness and accuracy of the sensing skin on a small scale, using concrete beams less than a metre wide, said the report.

“Our next step is to extend this to large geometries. We want to show that this will work on real-world structures,” added Pour-Ghaz.

Tags: research | concrete | structure | Skin | Damage | sensing |

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