For road construction companies, asphalt layer thickness has been a major topic for years. Why?

Because it is a crucial value to determine material control. By knowing the layer thickness, it is possible to prevent laying down too much asphalt. It also rules out putting down not enough asphalt, which can lead to premature wear of roads.

Both cases can cause problems for a construction company: Laying too much asphalt wastes money, because asphalt is an expensive material. So using the optimum amount of asphalt can be a major cost saving and increase profitability.

Too little material can lead to road damages, where construction companies might need to rework the project at their expenses.

Up to now, it was not possible to measure the material thickness during the paving process reliably, as no system was available on the market.

Therefore, MOBA has developed the first working system for thickness measurement worldwide, the MOBA Pave-TM (Thickness Measurement). The system has been successfully tested with some of MOBA’s long-term customers Beton- and Monierbau, Strabag and Schütz.

Complex problem, user-friendly solution

This is how this revolutionary system works: It measures the asphalt thickness constantly and contact-free via ultrasonic sensors (MOBA Sonic-Ski). It is mounted on the front part of the paver (in front of the screed) to measure the height from the ground to the sensor. Additional ultrasonic sensors are mounted on the rear of the paver to measure the height from the just paved material surface to the sensor (behind the screed).

Here is another mechanical construction from a side view.

A controller calculates the mat thickness through the difference between the height measurements of these different sensors.

This describes in simplified terms how the thickness measurement is realized. In reality, it is much more complicated as factors like the angle of the screed have to be taken into account.

The system displays the thickness values for both, the left and the right side of the screed. As these values are shown in real-time on a display, the operator on the screed can always check the thickness. If the thickness deviates, then one can quickly react and adjust the screed grade and slope. This way, the correct thickness can be realized directly and reliably.

In combination with the paving screed width and the paving length, the thickness measurement values allow to calculate the volume of the laid asphalt. That is very important because as already mentioned above, asphalt is an expensive material and the cost saving potential is extremely high as this example shows:

Road width: 10m, length: 10,000m

The final cost for this project is 4,104,000 €. Laying only one percent more asphalt means a cost increase of about 41,000 Euro. In many contracts, the calculated tonnage is assumed to be 100%. If the value is in the end less than 100%, a quality penalty has to be paid. If the value is larger than 105%, the additional tonnage will not be paid.

That explains why it is so important for construction companies to exactly know the layer thickness and be able to control the asphalt material.

MOBA’s new asphalt thickness measurement is another stepping stone towards building quality roads by making the roadbuilding process more efficient and sustainable.