Thermocouples consist of two different metals joined at one point, generating a voltage based on temperature changes.

Applications:Used for monitoring concrete curing in bridges and buildings, as well as assessing temperature changes in tunnels or large-scale structures. Thermocouples are suitable for high-temperature environments, such as during fire or heat exposure tests on structures.

Fiber optic cables sense temperature changes by detecting variations in light transmission through the fiber, typically based on the Brillouin or Raman scattering principle.

Applications:Widely used in monitoring large structures like dams, bridges, and tunnels. Fiber optic sensors can measure temperature over long distances, making them ideal for extensive infrastructure projects.

These sensors are made of ceramic materials that change resistance with temperature. Negative Temperature Coefficient (NTC) thermistors are more commonly used.

Applications: Suitable for monitoring localized temperature changes in structures like concrete elements, retaining walls, and structural foundations.

RTDs operate on the principle that the resistance of metals (often platinum) changes with temperature.

Applications: Often used in bridges, large-scale buildings, and tunnels to monitor temperature gradients over time, especially in regions with significant seasonal temperature fluctuations.