Concrete temperature monitoring is a basic measurement conducted in most projects in order to ensure proper curing of the concrete after placement. In some cases, the temperature history along with a calibration curve is used to calculate the real-time concrete strength based on the maturity concept. Wired temperature sensors and maturity meters have been used for these purposes in the construction industry for several decades. Some of these wired systems have logging capability unlike the basic ones that require a data logger to be connected to the wired sensor (e.g. thermocouple) at all time. For the earlier, a hand-held data logger is utilized to connect to the wire and extract the data from the logger (which is embedded in the concrete). In both systems, the thermocouple/logger is placed in the formwork somewhere on the rebar and the wire is extended to the edge of the form and its end is placed outside for access after pouring concrete.
In addition to the labor cost associated with using these wired systems (as explained in another blog post), there are several technical inefficiencies inherent to the wired temperature/maturity loggers and meters.
1. Wires sticking out of concrete often get cut in the construction job site. Construction workers try to keep the job site clean and if they are not aware of the temperature monitoring tests, they may cut the wires for safety reasons, etc.
2. The permanent data loggers (in the case of thermocouples), have to stay on the job site at all times. They can easy get damaged in exposure to humidity (e.g. rain) or physical damage due to impact at the construction job site.
3. When monitoring temperature as various spots for one concrete pour, the wires are accumulated in one location for ease of access. However, this can create a hassle of identifying and labeling them.
4. Moreover, the assembly of thermocouples requires some attention to detail! If not conducted properly, wires can cross over in the plug and cause reading errors.