Hardening of concrete is an exothermic process which begins immediately after cement comes in contact with water. However, like all chemical reactions, temperature plays an important role in determining the final strength of the cured concrete structure. Canzac recommends maintaining temperature between 10 and 32 0 C during placement and between 10 and 700 C during curing.
Effect of concrete curing temperature on compressive strength, cement.org
If the core temperature of concrete goes about 700 C it will cause the concrete to have high early strength development but consequently gain less strength in the later stage, resulting in lower durability of the structure overall. It has also been observed that such temperatures interfere with the formation of ettringite in the initial stage and subsequently its formation in the later stages is promoted; which causes an expansive reaction and subsequent cracking. Especially in the hot regions of India in summer, where the ambient temperature itself is over 400 C the concrete temperature can reach dangerously high values. With TruMonitor enabled TruTemp Concrete in place, mitigating measures such as using ice packs and chilled water can be taken as and when required.
When the temperatures go below 100 C, the reaction in concrete virtually stops. It may look hardened to the naked eye, but it does not attend its desired strength in 28 days. If such sections are used prematurely it can lead to disasters. By using TruMonitor for concrete curing, accurate temperature of the process can be knows and sufficient time can be given for the structure to gain strength.
The TruTemp Concrete module consists of a sensor which connects with the connector on the data logger unit. The sensor is mounted on rebars before concrete is poured. As soon as concrete is placed, the data logger starts recording the temperature and uploads it to the TruMonitor servers via GPRS connection. In case GPRS is not available, the TruMonitor app can scan the modules via Bluetooth and upload the data to the servers when internet connection becomes available. The app also allows site engineers to check the temperatures in real time whenever they choose.
While the sensors are lost in the concrete, they are cheap and easily replaceable.