Construction sites must maintain the right conditions once concrete has been poured to maximize the resulting concrete strength and minimize the curing time. This is especially a challenge in climates where temperatures can fluctuate quickly such as in Alberta, British Columbia and other parts of Canada.
Newly poured concrete must be maintained at the temperature recommended by the mix supplier and/or structural engineer to ensure optimum curing conditions. Maintaining this target temperature is a matter of mitigating temperature extremes:
Curing concrete in cold temperatures
At a minimum, concrete should be cured at temperatures above 7.2 degrees Celsius (45 degrees Fahrenheit). Below this temperature, concrete’s chemical reaction completely stops – which can result in costly delays and rework.
If temperatures are allowed to go below zero degrees Celsius (32 degrees Fahrenheit) before concrete has cured to at least 500 psi, the cement paste will not be able to resist the stresses applied by expansive, freezing pore water. This results in concrete curing with as little as 50% of its intended ultimate strength. This will almost certainly result in rework costs – sometimes requiring removal and replacement of entire slabs.
Curing concrete in hot temperatures
On the other hand, when concrete is allowed to get too warm, particularly above 30 degrees Celsius, or 86 degrees Fahrenheit, during the curing process it will also not reach its maximum strength over a 28-day period.
Applying more heat than is required for curing purposes can be costly in terms of fuel consumption. Additionally, unevenly applied heat can result in concrete defects such as cracking which, in many cases, will require refinishing costs.
In order to maintain moderate temperatures that maximize concrete strength, construction companies have ways in which they can control the curing environment. These include the following:
- Using industrial-grade heaters
- Setting up fans to even temperature throughout areas
- Using periodic wet-downs or water spray
- Covering curing concrete with insulating material or blankets
- Setting up curing ponds
Monitoring and getting alerts
Regardless of the environmental control setup, conditions can change. This means that it is vital to have real-time monitoring of temperature so that adjustments can be made to maintain quality and maximize concrete strength. It’s also valuable to have a record of past temperatures so you can know the exact role temperature may have played in the curing process.
Construction sites can utilize as system of remote sensors that monitor temperatures both in the surrounding air, as well as right inside curing concrete slabs. With numerous sensors installed on a site, and an easy-to-read dashboard showing real-time temperature and humidity levels, a construction site superintendent knows when and where any problems are arising while there is still time to do something about it.
Alerts are put in place so you are notified on a mobile phone if exceed thresholds. Getting such an alert in time to rectify the situation can save a construction project hundreds of thousands of dollars, let alone keeping the project on-time without needing to redo phases if things were to go awry.
As an experienced company providing services and expertise for construction sites in Canada, WesternOne identified the need to monitor temperatures and humidity levels on industrial-grade concrete pours. Thus, in 2017, the company invested in developing a smart technology for worksites called WEDGE. It’s a fully-integrated, reliable remote monitoring service providing accessible data 24/7 from the worksite, to your smartphone, tablet or computer. WEDGE excels in applications for curing concrete in harsh conditions.
Image: Each of these robust sensors can be enveloped directly in a concrete pour, providing valuable data in real-time to a dashboard on the user’s mobile phone.