Desarrollo de materiales cementicios intrínsecamente sensores basados en la adición de microhilos ferromagnéticos para su uso en evaluación estructural (SENCEMHIL)

La motivación del proyecto radica en la necesidad de disponer de sistemas y procedimientos más eficientes y eficaces, para el control estructural de infraestructuras de ingeniería civil. El paradigma de convertir el hormigón estructural en un material inteligente capaz de autodiagnosticarse, o de permitir un diagnóstico rápido y fiable, es la base científico-tecnológica que sustenta el presente proyecto coordinado.

Objetivos del proyecto:

Diseño, desarrollo y predicción de la vida útil en servicio de nuevos materiales inteligentes en base cemento con capacidad intrínsecamente sensora, que posibiliten la inspección in-situ y monitorización inalámbrica del estado tensional de estructuras de hormigón.

Desarrollo de micro/nanomateriales con propiedades piezoresisitivas y magnetoresistivas, que puedan ser fácilmente integradas/incorporadas al hormigón para desarrollar el composite cementicio intrínsecamente sensor.

A novel mechanical stress sensor based on the use of amorphous and nanocrystalline ferromagnetic microwires was developed by the research group. A magnetic microwire on cement-based composite (MMCC sensor) are embedded directly, as a simple extra-aggregate in a structure of cementitious material. So that measures the state of mechanical / strain of the structure of that structure in a continuous way and without affecting their structure or state of tension.

Microwires dimensions	Micrograph of the glass-coated microwire by SEM

Innovations and advantages

• This type of sensor can reduce the price up to 80% compared with strain gages, which is the cheapest technology among alternatives.
• Allow non-contact measurement by simple electromagnetic induction. When the depth of embedding is high. Two thin wires to get the signal from the sensor are embedded.
• The duration and strength is considerably higher than other alternative technologies. The microwire has a ferromagnetic core and an insulating glass coating obtained directly from its fabrication. The composition of glass-coating allows it to be resistant to the alkaline environment of concrete. Moreover, the microwire once treated, their magnetic properties are not changed in hundreds of years.

Measuring systems are simple because they work at low frequency and power consumption and can be implemented by low performance microcontrollers.

MMCC sensors	MMCC sensor embedded in concrete sample