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Recent Advances on SHM of Reinforced Concrete and Masonry Structures Enabled by Self-Sensing Structural Materials
Filippo Ubertini * 1 , Antonella D'Alessandro 1 , Austin Downey 2 , Enrique García-Macías 3 , Simon Laflamme 2 , Rafael Castro-Triguero 4
1  Department of Civil and Environmental Engineering, University of Perugia, Italy
2  Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA, USA
3  Department of Continuum Mechanics and Structural Analysis, School of Engineering, University of Seville, Spain
4  Department of Mechanics, University of Cordoba, Campus de Rabanales, Cordoba, Spain

10.3390/ecsa-4-04889
Abstract:

Structural Health Monitoring is aimed at transforming civil structures into self-diagnosing systems able to automatically reveal the occurrence of a fault or a damage after a critical event such as an earthquake. While data science is presently experiencing a tremendous development, leading to the availability of powerful tools and algorithms that extract relevant information by effectively fusing data provided by different types of sensors, one of the main bottlenecks still limiting the development of SHM in the filed of civil engineering is the general lack of reliable sensing technologies that are effectively applicable to the large scale. A very promising solution to such a large scale challenge would be using the same construction materials for strain sensing and direct damage detection. In this view, the authors have recently proposed smart concretes and smart bricks that are piezoresistive concretes and clay bricks obtained by doping traditional construction materials with conductive nano- or micro inclusions. These novel multifunctional materials have the ability to provide measurable electrical output under application of a mechanical load and to provide information useful for damage detection, localization and quantification. The paper introduces both technologies, discusses their potentials and illustrates their application to paradigmatic structural elements arranged in the laboratory. The presented results contribute to showing the revolutionary impact that smart concretes and smart bricks may have in the near future on SHM of concrete and masonry structures.

Keywords: smart concrete; smart brick; structural health monitoring; earthquake-induced damage detection
Comments on this paper
Hugo Avila-Paredes
Some questions
Dear authors,
This is a very nice work. Hope I didn´t overlook some information. Could you please comment on whether the aging of the metal contacts affect the electrical measurements on the smart bricks/cement? and if so, how is that aging prevented? Could cracks preferentially propagate through the cement-metal contact interphases? Regarding the NW´s for high temperature applications, what was the titania phase employed? Was the material doped/undoped?

Thanks in advance.

Filippo Ubertini
Ageing of contacts
Dear Colleague,
thank you for your interest in our work. The long-term stability of the contact resistance is indeed an important issue that needs to be investigated. We have not done it so far on a systematic way but I can comment that we currently feel that the best way to go, in bricks, will be to get rid of point electrodes and use metal sheets, such as copper sheets, as electrodes on top and bottom surfaces of the bricks. These electrodes will therefore be protected by the mortar layers and will allow a more uniform and wider contact area. This will be the object of future work and we already have nice preliminary results. Ageing will be studied thorugh accelerated ageing tests. For cement-based sensors the problem is more complicated but we are thinking of covering the electrodes with concrete.

There is no evidence so far of cracking through cement-metal interphase but, again, this is an interesting aspect to look at, thank you.

Concerning the fabrication and phase of titania used for smart bricks, you could have a look at the following, just released, paper:
http://iopscience.iop.org/article/10.1088/1361-665X/aa98c2 To answer in brief, we used undoped solid titania particles.
Thank you very much again for your interest,
regards,
Filippo Ubertini
Hugo Avila-Paredes
Thanks much for your reply



 
 
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