Tuesday, November 28, 2006

0 Self Sensing "Smart" Concrete - Part 1

Sometime in an earlier post, I briefly described how a professor in my university, Dr. Deborah Chung delivered a lecture on her new invention - smart concrete. I haven't elaborated on what exactly she spoke, and I will do that now.

Dr. Chung is a materials-science scientist and professor at our university. She holds degrees from a number of elite universities in the U.S and has a PhD. I have read a little from her autobiography and I was very impressed and motivated.

Some major disasters around the world mainly happen through engineering failures. Be it man made or natural, a breach in the strength of materials, especially those applied in construction, can mean anything from total collapse of the structure in question to damage to property and loss of human life.

Take for example the levee embankments in New Orleans during Hurricane Katrina. Construction materials were clay deposits interspered with silt or sand seams. It is said that before the flood, the levees themselves had been sinking due to improper sheet metal pilings. They weren't set deep enough. Some of then were only 10 feet deep while others were as deep as 25 feet. Those deep enough could keep the flood at bay than others. With shortage of funds, repairs lagged. I do not know the exact nature of the failure but engineers claim that improper pilings, topping of the huge water surge and erosion of foundational soils were among the main causes of the levee failure. I even watched this on Discovery Channel.

Imagine a situation where the same levees are made of smart concrete that can monitor stress and deformation in real time. You set an acceptable baseline for the deviations. In a situation where the deviation exceeds the limit, an alarm is triggered and engineers are immediately notified.

Or take the situation of a smart roads being able to weigh heavy duty vehicles that move on it, especially at borders or bridges. Think of what that could mean for traffic monitoring and homeland security.

Embedded road sensors have been implemented in areas such as Washington D.C. The Anacostia Freeway that is part of the Interstate 295, has a weight sensor planted under the pavement at the naval station. This helps catch overloaded vehicles that are potentially harming the roads and are a source of tax for the city.

However, a budget of 1 million dollars for a virtual weighing station is too much. This is where smart concrete could come in. Although construction costs with smart concrete could shoot up by 30%, Dr. Chung believes that this option is cheaper than embedding sensors under pavements. At this point in time, it is the high costs that discourages the industry to adopt its use.


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