Development of cementitious material intrinsically sensor for structural evaluation based on ferromagnetic microwires (SENCEMHIL)

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