The Blanket Project – Monitoring Temperature of Concrete in the Cold Weather
Concrete temperature monitoring becomes more critical in the cold season as low temperatures can decrease the rate of strength development and therefore, delay the subsequent construction operations such as formwork removal and post-tensioning. Mass concrete placements can also experience significant temperature gradients under these conditions.
In order to ensure proper strength gain in concrete structures during the winter-time construction, new placements are generally protected by providing an external source of heating. In mass concrete placements, protective blankets are used to cover concrete and use the heat generated from the mass concrete itself to decrease the temperature difference between the surface and inner parts of the concrete element.
Various systems such as thermocouples and loggers can be used to monitor concrete temperature. In most of these systems, wires are coming out of concrete that need to be protected from damages on the construction job site. The data loggers that are attached at the end of thermocouple may experience malfunctioning at very low temperature ranges. Moreover, the manual process of installation of these types of sensors and data collection become more difficult in cold weather conditions. More specifically, when heat blankets are used, it is a challenge to lift them and find the end of the temperature cables!
SmartRock2 is a wireless concrete temperature sensor that has been designed to address these challenges. It is fully embedded in concrete at the time of placement in order to protect the sensors from physical damages. Moreover, the temperature data that is recorded on the sensors can be easily downloaded wirelessly using a free smartphone app (on both iOS and Android devices). The app immediately analyzes the data to show the minimum and maximum temperature values and temperature history. The results and a full PDF report can also be instantly shared through the app with coworkers on the project. Many projects worldwide utilize SmartRock sensors to improve the speed and efficiency on the job site. Knowing the real-time results, contractors can optimize the heating process, decrease their energy costs, and optimize the subsequent construction operations. In addition, SmartRock sensor can be used to estimate the in-place strength of concrete based on the maturity concept (a ASTM C1074 standard test method).