According to Article 71.5.3.1 of the Structural Concrete Instruction, EHE - 08The temperature of the concrete mass at the time of pouring into the mould or formwork shall not be less than 5 °C and it is prohibited to pour concrete on elements (reinforcement, moulds, etc.) whose temperature is below zero degrees Celsius.
In general, concreting shall be suspended whenever the ambient temperature is expected to fall below zero degrees Celsius within 48 hours.
The following can be used in the manufacture of concrete setting accelerator additives o hardening accelerators or, in general, of any specific anti-freeze product for concrete, at the request of the construction site .
In the commentary section of the above article, cold weather is defined as the period during which the following conditions exist for more than three days:
- The average daily air temperature is less than 5 °C.
- The air temperature does not exceed 10 °C for more than half of the day.
The hydration of the cement paste is delayed by low temperatures. In addition, frost can permanently damage the concrete when it is not yet hardened if the water contained in the pores freezes and breaks up the material. Consequently, steps must be taken to ensure that the rate of hardening is adequate and that frost damage does not occur.
If the proposed weather station is available and the driver of the truck mixer is provided with a digital or infrared thermometer, this will allow the temperature of the concrete to be taken at the time of unloading on site. The Conex system will directly check compliance with the conditions specified above, and if a RASPBERRY is incorporated into the system, the weather information will always be available even if the plant computer is switched off and the specified cold weather conditions can be assessed.
