General contractors
Why do general contractors use concrete sensors?
Table of Contents
Main challenges as a contractor
Optimising your time and resources better
Anyone who has worked with concrete knows how stressful it can be to have an entire team just waiting for the concrete to achieve a certain strength. Sometimes, this wait is necessary, however in many cases, the structure may have reached desired strength already. This unnecessary wasted waiting game, adversely effects time, resource and project programme, valuable hours lost and delays incurred. Unsurprisingly, this situation is far too common and needn’t be.
This pointless additional waiting is typically caused by relying only on break tests. This is a flawed method, as the strength of the samples and the strength of the concrete structure vary by the (also called specimens) might not be the same as in the concrete element. Even if you place the samples close to the structure to simulate the same curing conditions as the structure, the concrete elements usually have a much higher mass. This means 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 challenging with making the samples properly, transporting them, performing the compression tests and then getting the results. Potential delays in getting the results can leave you waiting even longer. With all this uncertainty regarding concrete strength, it can be tough to plan for resources or use time more efficiently.
Time consuming reporting of temperature and strength development
Fulfilling the specifications is essential for all contractors, and within concrete requirements usually means documenting temperature development, final strength and sometimes early strength. 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 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 minimal information. So they will give you the strength at the specific test time but will not tell you much about the overall strength development process.
Assuring quality and safety
The daily life on a job site is quite hectic. The formwork needs to be ready for when the concrete truck comes, and then the concrete needs to be poured, cured and finished, while other building activities are also required. In this tight schedule, it might be hard to find someone with the time to make a good report about the process manually. Then if something goes wrong, it would be tough to figure out where the issue came from. Furthermore, if the issues are not found early, it might become a safety problem for the workers on the project and the users of the structure.
Could using concrete sensors help?
You could address the previous challenges 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 maintaining a high safety standard.
This is what concrete sensors, specifically the Maturix system, will allow you to do.
How does it solve the problem?
The Maturix system is a solution for intelligent temperature and strength monitoring in concrete. The system lets you see the temperature and strength development in real-time from any device. This allows you to know what is happening inside your concrete in terms of temperature and strength development.
The Maturix system consists of one or multiple transmitters, sensor/s and the Maturix In-situ platform. Sometimes, you can add a Sigfox gateway to the system to improve the network coverage. You can see a diagram of the whole system below:
Using thermocouples cast directly in the structure and connected to a transmitter, you can continuously measure the temperature inside the concrete. The collected data is sent wirelessly to the cloud platform, and the software automatically calculates the maturity and strength based on the history data and the concrete mix. You can then follow the strength development process. The data is accessible from any device, thus smartphone, tablet, or computer, with an 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 you set up the online platform and have a maturity calibration (only relevant for strength monitoring).
Online platform
1. Set up your project in the online platform
Installation
2. Install the thermocouple
3. Connect the transmitter
4. Pour the concrete
5. Get results in real time
Other contractors that also use Maturix
There are many contractors that are already benefiting from using the Maturix system:
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 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. Luckily, 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, the client could solve the issue efficiently and quickly thanks to remote access to the temperature data from a smartphone.
Receive alarms and keep issues under control
When working on a project, many things 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 often the project site is far from other infrastructures, making it challenging to keep an eye on everything. You may be home on the weekend, hoping your concrete is doing fine.
With Maturix In-situ, you could be home and 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 specific values, if the strength is reached or if there is data coming in. Say goodbye to the long drives to check if everything is okay. Now you can accomplish the same by looking at the data from your phone or laptop.
Automatic documentation
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:
- Documentation of maximum reached core temperature in structure
- Documentation for thermal differences in cross section
- Ambient climate temperature
- If castings are done against old and cold concrete, the temperature of both existing structure and newly fresh concrete should be recorded and documented
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 calculate the maturity and strength from the temperature readings, this will involve much manual work and increase the risk of errors.
With Maturix, all the calculations will be done automatically. This means you can use the temperature readings for the thermal monitoring documentation and strength monitoring. Moreover, all 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 contain data from the concrete, temperature, ambient humidity, and KPIs like maximum temperature, production time, etc. Everything is done automatically without using labour – we call it 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 be irreparable damage.
For these reasons, you must monitor the temperature under both hot and cold temperatures. You could do this with traditional data loggers, which 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, create reports on 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 is 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:
- Brownish colouring
- Reduced heat development
The brownish colour is often “just” an architectural/design challenge, while the reduced internal heat development from the hydration will significantly impact the curing process. Reduced heating can be an advantage on 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 must 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):
Civil infrastructures
- Bridges
- Tunnels
- Airports
- Railways
Utility constructions
- Nuclear Plants
- Spillway and Dams
- Marinas and Harbors
Building structures
- High-rise buildings
- Commercial and administrative buildings
- Hospitals
- Foundations
Precast concreting
- Hollowcore, beams and other prestressed concrete structures
- Slap reinforced elements, sandwich structures, stairs etc.
In concreting methods like:
- Mass concreting
- Post-tensioning
- Tilt-up construction
- Slip- and jump forms
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
- Total cost of this would be 681€
The Gaia will be used for 6 monitorings/month x 12 months= 72 castings.
If you use our 10 meter thermocouple 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€.
- This means total cost for cables are 300€
So the total cost for conducting 72 monitorings in a 12 months period for this example would be 981€ or 13.6€/monitoring including all equipment and service costs.
Price comparison:
Maturix
1 monitoring per 75m3 of concrete: 0.18€/m3 concrete used
Bluetooth based competitor
Averaging cost: 1.3-1.8$/m3 concrete used (costs per bluetooth units are usually 75€-185€)
Price differences
~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€.
