Jobsite Calibration Guidance
Before you can use the strength prediction functionality of Converge ConcreteDNA on your jobsite a calibration must be performed.
ConcreteDNA uses the maturity method to determine the compressive strength of concrete. The maturity method involves a calibration process performed in a lab for each of the mixes used on your project. This process entails preparing cylinder samples and performing break tests at set intervals to measure its strength gain over time.
You are responsible for appointing and instructing a lab to perform break tests of your concrete mix in accordance with the instructions below to ensure reliable results in compliance with ASTM C1074.
- Find a Lab
They will store your cylinder samples in temperature controlled water bath(s) and perform break tests in line with your instruction. They will also need to read the DeWalt sensors embedded in control cylinder(s) through the Converge app. The lab may come and prepare the cylinder samples at your jobsite and transport them to their facility.
- Agree crush schedule - What is appropriate and possible for your job site?
The calibration will take a total of 28 days with the crushes taken in the first 7 days being the most important.
There is a choice between two crush schedules that you can agree with your lab. Please seek advice from DeWalt when making the choice.
Either 18 or 28 cylinder samples will be needed.
These schedules can be tweaked (+/- 24 hours) to fit into lab opening hours but the crush times must always be clearly documented.
- Basic Crush schedule
- Full Crush Schedule
- Receive DeWalt sensor delivery
You will need to install one or two Signal sensors in the cylinders and may provide the lab with a Live hub to collect temperature readings.
- Fix a date
Coordinate the concrete delivery with when the lab can come to take the samples. You will also need a DeWalt sensor(s) to install into a cylinder sample. The quicker you get this process under way the quicker you can get started with the Converge system.
- Register Converge Sensors ready for installing into Cylinder sample(s)
Register the allocated sensor(s) to the Converge Platform ready for installing into a cylinder sample.
- Install Signal sensor into cylinder sample and MARK cylinder
Install the sensor into a cylinder following the diagram below and mark the cylinder. This cylinder will not get crushed and will sit inside the water tank monitoring any slight temperature variation during the whole 28 day calibration process.
- Receive and pass on crush results
Once you have received your lab crush data share this, along with any other relevant information, with DeWalt who will be responsible for performing the curve fitting. Your mix will then be uploaded to the platform, ready for use.
Note that the full cycle takes 28 days but generally, once the concrete has exceeded its design strength, a curve can be produced (this often occurs between day 7 and 14). Contact DeWalt for further questions or enquiry.
Click Calibration Video for further info