Concrete Curing: Advice In Temperature Monitoring

We are currently moving into the depths of summer, nearing the end of sun burned grass, and towards the oranges, reds, and yellows of fall. Summer brings hot weather, whether humid or dry. For one particular group of our customers, that means a change in how the produce, implant, and monitor their product.

Construction is an industry that we haven’t written a lot on. There are many reasons for this, none of which are satisfactory. The most relevant, is that for us here at Dickson, construction, specifically concrete, is a bit foreign. While all of us have opened a refrigerator or freezer, not all of us have been to a construction site, or in a concrete testing lab.

Yet, we engage in conversations with customers who are involved in the construction process. So, in this month’s catalog, we thought we would tackle one aspect of construction: concrete curing.

What is it?

For the uninitiated but interested, concrete curing is the process of moistening concrete that has already been poured or set, over time, to increase its strength and durability. Almost all concrete you see has gone through some sort of curing process.
What does Dickson have to do with it?

Temperature and humidity of course! Controlling the temperature and humidity of the ambient air around the concrete and the concrete itself are essential to the curing process. Monitoring that temperature is essential for testing labs, and for some on site curing as well. Keeping the concrete moist at certain temperatures and for certain amounts of time is key to both accelerating the curing process, and further strengthening the concrete.

A deeper dive:

Concrete curing takes on many different forms, and thus there are different attitudes, processes, and yes, temperatures/RH levels that are necessary for curing specific concrete in specific applications. We will talk about those different forms at a later date, but at the moment, we’d like to focus in on something that we can directly influence, the type of temperature and humidity monitoring that you are doing while your concrete is curing.

First thing’s first: do what your auditor says. (For those that were the uninitiated but interested, construction companies, concrete manufacturers, and city works get audited too.) Listening to your auditor is almost always the number one piece of advice that we will recommend here at Dickson.

Types of Temperature Monitors:

There are a 3 distinct “types” of temperature monitors: data loggers, chart recorders, and indicators. These three different types all measure the temperature of an environment at a specific point. They do so through a temperature sensor, which can be anything from a mercury bulb to a K-Thermocouple Probe. They then display that information on a . . . well, a display. For indicators, that is all they do. For data loggers and chart recorders, that information (the temperature/humidity measurement and the date and time) are stored as information. For data loggers, that data is stored in the device for later download (via software) onto a computer, or sent to a cloud application or server for remote access. For chart recorders, it is written down as it is recorded onto a paper chart.

This may all seem a little elementary, but I’d ask you to keep it in mind as you begin to think about what product is right for you. The two easiest ways to narrow down what “type” of temperature monitor is right for you, is to ask yourself if you need or want temperature data over time, and then what variable you will be measuring (in our case, temperature, or temperature and humidity.) If you need temperature data over time, you need a data logger or chart recorder. If you only need to gather temperature data once in a while, in other words just “checking in” with your process every once in a while, a temperature indicator will do just fine.

For most testing labs and on site curing processes, a data logger or chart recorder is either convenient or necessary to have: your auditor may want some proof the concrete you are laying has been cured at a specific temperature and humidity over a specific amount of time.

What you should consider before you buy:

Location, location, location. We can’t stress this one enough. After variable and data, this is the most important for construction companies who are curing concrete: where are you doing the curing? Will you be on site, in your plant, or in a testing lab? Somewhere else? Think about where you will be curing, and what type of effect that will have on the rest of the features that come with a data logger or chart recorder. If you are on site, you may not have a power outlet close, so battery power would be essential. If you are in a harsh environment, you may need a durable, robust logger to deal with the elements. If you are in a lab, you may need more than one logger to understand how temperature fluctuations in one test differ from those in another. The list goes on and on.

Probe. This consideration can be rephrased as a question: what are you measuring? For some, they want a remote temperature probe to measure the actual temperature of their concrete. So, that probe must be submersed in the concrete, and thus should probably be a K-Thermocouple Probe. If you are looking to measure the ambient air during ponding or test immersion, you may want to know the ambient humidity of the air right above your concrete. This would call for a digital temperature and humidity sensor.

Trends versus Data Points. A chart recorder is going to only show you temperature trends, not exact data points. If you simply want to glean the general temperature and/or humidity range of your curing application, these will work just fine. However, if you would like to know exactly what temperature and/or humidity your concrete was at around 4:30PM, or any other time (along with getting graphing capabilities and much more) you will need a data logger.