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Empowering smart buildings with self-sensing concrete for structural health monitoring

Given the increasing number of building collapse tragedies nowadays (e.g., Florida condo collapse), people gradually recognize that long-term and persistent structural health monitoring (SHM) becomes indispensable for civilian buildings. However, current SHM techniques suffer from high cost and deployment difficulty caused by the wired connection. Traditional wireless sensor networks fail to serve in-concrete communication for SHM because of the complexity of battery replacement and the concrete Faraday cage. In this work, we collaborate with experts from civil engineering to create a type of promising self-sensing concrete by introducing a novel functional filler, called EcoCapsule- a battery-free and miniature piezoelectric backscatter node. We overcome the fundamental challenges in in-concrete energy harvesting and wireless communication to achieve SHM via EcoCapsules. We prototype EcoCapsules and mix them with other raw materials (such as cement, sand, water, etc) to cast the self-sensing concrete, into which EcoCapsules are implanted permanently. We tested EcoCapsules regarding real-world buildings comprehensively. Our results demonstrate single link throughputs of up to 13 kbps and power-up ranges of up to 6 m. Finally, we demonstrate a long-term pilot study on the structural health monitoring of a real-life footbridge.