Why do general contractors use concrete sensors?
Difficulty optimizing the use of time and resources
Any person that has worked with concrete knows how stressful it can be to have a full team just waiting for the concrete to achieve a certain strength. Sometimes, this wait is necessary but many others, the structure might have reached the strength and you may now know it. This will waste many valuable project hours and the whole schedule might be delayed. Sadly, this situation is much more common than you may think.
This unnecessary wait is normally caused by relying only on break tests. The challenge with this method is that the strength in the samples (also called specimens) might not be the same as the one in the concrete element. This happens because even if the samples are placed close to the structure, to simulate the same curing conditions as the structure, the majority of the time the concrete elements have a much higher mass. This means that the structure will generate much more heat, due to the exothermic reaction, and develop strength much faster than the sample. So you may be waiting 1, 2 or even 4 additional days while the structure has already reached the desired strength.
Moreover, break tests provide only one information point per compression test. So if you wanted information every hour you would need 24 samples only for a day. Logistics can also be a challenge with making the samples properly, transporting them, performing the compression tests and then getting the results. Potential delays in getting the results can, again, leave you waiting even longer. With all this uncertainty regarding concrete strength, it can be extremely difficult to plan for resources or try to use time more efficiently.
Time consuming reporting of temperature and strength development
Fulfilling the specifications is important for all contractors, and within concrete requirements normally this means documenting temperature development, final strength and sometimes also early strength. The process of recording temperatures in many points of the structure can be very time consuming. If a manual data logger is used, you will need someone to keep checking the values, write them down and then create a report. If there is an issue, especially at night, it will not be detected until many hours later. This makes the process very resource intensive both in terms of time and cost. Monitoring strength development can be even more difficult, you can use break tests or other test methods but many of these offer very limited information. So they will give you the strength at the specific time of the test but will not tell you much about the overall strength development process.
Assuring quality and safety
The daily life in a job site is quite hectic. The formwork needs to be ready for when the concrete truck comes, then the concrete needs to be poured, cured and finished all while other building activities are also required. In this tight schedule, it might be hard to find someone that has the time manually to make a good report about the process. Then if something goes wrong, it would be very hard to figure out where the issue came from. Furthermore, if an issue is not catched early on, this might become a safety issue both for the workers on the project but also for the users of the structure.
Could using concrete sensors help?
All the challenges explained above could be addressed if you knew the current strength of the structure. Imagine if you could see the concrete strength at any point in time. Then, you could start optimizing project schedules, saving time and using your resources more efficiently while still maintaining a high safety standard.
This is what concrete sensors and more specifically the Maturix system will allow you to do.
Benefits of using concrete sensors as a general contractor
How does it solve the problem?
The Maturix system is a solution for intelligent temperature and strength monitoring in concrete. The system enables you to see the temperature and strength development in real time from any device. This gives you the opportunity to know exactly what is happening inside your concrete in terms of temperature and also in strength development.
The Maturix system consists of one or multiple transmitters, sensor/s and the Maturix In-situ platform. Sometimes, a Sigfox gateway can be added to the system to improve the network coverage. You can see a diagram of the full system below:
By using thermocouples that are cast directly in the structure and connected to a transmitter, the temperature inside the concrete is measured continuously. The data is sent wirelessly to the cloud platform. The software automatically calculates maturity and strength based on the history data and the concrete mix and the strength development process can be followed. The data is accessible from any device, thus smartphone, tablet or computer with internet connection via the web portal or app and provides real-time insights into the actual curing status inside the structure in several positions for each cast.
How do you set it up?
The Maturix system offers a fast and simple installation once the online platform has been set up and you have a maturity calibration (only relevant for strength monitoring).
1. Set up your project in the online platform
2. Install the thermocouple
3. Connect the transmitter
4. Pour the concrete
5. Get results in real time
Which are the benefits of using sensors?
Follow the temperature and strength development in real-time
As we mentioned before, the Maturix system allows you to follow the temperature and strength development in real-time. This will help you to keep your project plan, make a more efficient use of resources, ensure good concrete quality and fulfil the documentation and quality assurance requirements. Moreover, it will allow you to take proactive decisions based on data instead of using data passively.
For example, one of our clients experienced that one day, while being at home during the weekend, there was a sudden drop in temperature in his concrete. He asked a colleague to check the job site and found that one of the concrete covers had flown away. Luckly, it was not too late so the cover was placed back and the concrete cured successfully. The situation could have been disastrous, the concrete could have frozen (the project was located in Norway) causing innumerable delays to the rest of the project and a lot of added stress. Instead, thanks to the remote access to the temperature data from a smartphone, the client could solve the issue easily and fast.
Receive alarms and keep issues under control
When working on a project, there are many things that can go wrong. The heating or cooling equipment might break, the covers might blow away or the concrete may cure slower than expected. This added to the fact that many times the project site is far from other infrastructures makes it challenging to keep an eye on everything. You may be home on the weekend hoping that your concrete is doing fine.
With Maturix In-situ, you could be home and simply check on your phone how the cast is doing at any time. Moreover, you can also set alarms to get notified if the temperature drops or exceeds certain values, if the strength is reached or if there is data coming in. Say goodbye to the long drives done to check if all is okay, now you can accomplish the same simply by looking at the data from your phone or laptop.
A thermal control plan is often a requirement on big scale projects and on publicly owned (infrastructure, utility buildings etc.).
Requirements might include requirements such as:
In the table below, we have compared the procedure of creating the thermal control documentation with a traditional data logger against doing it with a smart concrete sensor.
|Datalogger||Smart Concrete Sensor|
|Gather Data||Extensive work of gather information, as distance from office to concrete both on job sites and precast facilities might be long||Two types of maturity sensors are available: Short-range (bluetooth, wifi etc.) and Long range (GSM, Sigfox, Lora etc.) If true remote collection is wanted, then you have to find a long range solution like Maturix|
|Transfer to PC||When datalogger is brought to the office from the casted concrete data has to be transfer to a PC||This process will be done automatically.|
|From Raw Data to Charts||The raw temperature readings has to be upload to an excel sheet , aligned and charts made||This process will be done automatically.|
|From Excel to Word to PDF||Charts and data tables transferred to word and made into a PDF||This process will be done automatically.|
If you want to also calculate the maturity and strength from the temperature readings, this will involve a lot of manual work and increase the risk of errors.
With Maturix, all the calculations will be done automatically. This means that you can use the temperature readings for the thermal monitoring documentation, but also for strength monitoring. Moreover, as all data the data is automatically stored and formatted in reports in the Maturix in-situ platform. These reports are ready to be exported, in PDF or another format, and printed anytime. The reports are updated every 10 minutes when new data is received and contains both data from the concrete, temperature, and the ambient humidity and KPI’s like maximum temperature, production time etc. Everything done automatically without any use of labor – this is what we call automatic reporting.
Easier cold and hot weather concreting
Concreting under either very cold or very hot conditions can make concreting extremely challenging. In hot weather conditions, with the temperatures rising, you might risk exceeding the maximum recommended temperature, normally set to 70°C. Having such a high temperature (often in the core) could cause your concrete to:
- Gain a very high early age strength, which may seem an advantage but research shows that curing the concrete too fast can reduce its long term strength.
- Have high temperature differences between core and surface which may cause later formation differences in later stages. This will increase the risk of cracks and imperfections forming on the concrete.
In low weather conditions, normally defined as three consecutive days of temperatures below 5, the curing speed is very low which means that the strength will be gained very slowly. Moreover, if the concrete falls below a certain temperature the reaction will stop completely and there may cause irreparable damage.
For these reasons, it is very important that you monitor the temperature under both hot and cold temperatures. You could do this with traditional data loggers but these can be very labour intensive and time consuming. A better option is to use the Maturix system (composed of transmitters and an online platform) to gather your temperature, maturity and strength data, get to see it and create reports in the online platform and even invite external users to view it.
Get the most out of green concretes
One of the new big concrete trends globally are the new green concrete mixes with a low (at least lower) carbon footprint compared to traditionally used concrete. Some of these new concrete mixes substitute part of the limestone or calcium silicate, present in normal concrete, with clay products.
The new types of concrete often face the challenges of:
- Brown-ish coloring
- Reduced heat development
The brown-ish color is often “just” an architectural/design challenge, while the reduced internal heat development from the hydration will have a significant impact on the curing process. The reduced heating can be an advantage on very big and thick castings, where you often use retarders and cooling to avoid high maximum and high-temperature variations in the cross-section. But the low heat development can also be a challenge on most castings where you need to achieve a certain early strength fast. Therefore, it is crucial to keep track of the temperature and strength development of the concrete by using sensors.
Which structures can I use the sensors for?
Concrete sensors can be used for many different construction structures and fit within various methods. Below, you can see a list of examples of structures where we have seen clients using Maturix for (but not limited to):
In concreting methods like:
How much does it cost to use Maturix as a contractor?
So let’s see an example of how the pricing could look:
If you use one Gaia 200 for 12 months. This equals costs of 465€ for the hardware and the cost for connectivity and software would be 18€/device/month or 216€ for 12 months
The Gaia will be used for 6 monitorings/month x 12 months= 72 castings.
If you use our 10 meter probes and use 2 meters for every casting, then the cost for cables would be: 72 castings x 2 meters = 144 meter needed => 15 x 10 meter probes needed. The cost per cable is 20€.
So the total cost for conducting 72 monitorings in a 12 months period for this example would be 881€ or 12.2€/monitoring including all equipment and service cost.
1 monitoring per 75m3 of concrete: 0.16€/m3 concrete used
Bluetooth based competitor
Averaging cost: 1.3-1.8$/m3 concrete used (costs per bluetooth units are usually 75€-185€)
~90% cheaper per monitoring
This is of course just a case example. We know our pricing depending on lengths of cables, how much you embed and such brings our cost per measurement in total cost in the range between 3-15€.
Do you want to try wireless sensors?
We are currently running a campaign offer for an easy and affordable trial of our concrete sensors. Our trial packages have no strings attached, this means you have fully purchased your hardware and don’t need to return it. After the first 3 months service, the subscription will automatically stop. If you want to continue, then you have the option to either opt in for a yearly or monthly subscription.