Close to Heilbronn, a new industrial area required preparation for a complete infrastructure of industrial halls, administration buildings, roads, parking lots and gardens. Due to the heavy earthworks carried out during its foundations, sewer lines and cable trenches, the base was raked up completely. All the holes had to be refilled and compacted layer by layer. Although the base was very inhomogeneous, a well compacted and uniform result was required. For this purpose, the customer decided on a very heavy single drum roller in the 25-ton class for compaction. The machine was already equipped with a compaction measuring system from AMMANN itself, but without mapping and reporting capabilities.

The AMMANN Roller - General technical data

Working width [mm] 2240

Operating weight [kg] 25330

Centrifugal force [kN] 460 / 340

Amplitude [mm] 2,20 / 1,10

Frequency [Hz] 28 / 34

Working speed [km/h] 9,5

Static linear load [kg/cm] 78,5

MCA installed on the AMMANN ASC 250

MOBA OEM colour display for AMMANN AMMANN monochrome display with printer

The installation of the AMMANN system gave MOBA the opportunity to compare both units side by side. Mounting the sensors at the same position all measured equal values.

MOBA acceleration sensor black, AMMANN grey

Only one roller was used at the construction site. Therefore, the customer chooses a GNSS antenna with SBAS accuracy. With the accuracy of the antenna used, and the glide filter switched on, the “pass to pass” accuracy was suitable to achieve precise results for the mapping data. After installation, two operators were trained. In only half an hour, the operators were able to understand the system and work with it properly. The operators commented,

“The system is easy to understand, the visualisation is clear, the functions are self-explaining- no need to study the operation manuals in depth”.

The exceptional work carried out by the MCA installation can be seen in the following pictures:

Compaction of a gravelled base by rolling up static

The first task after installation was the final compaction of a 35 x 50m area that was covered with gravel. With this big roller, the compaction on the main surface was achieved in only one pass. In the area of the trench, six passes were needed. It’s easy to see how accurately the machine was used. Less overlap, fewer gaps – means efficient use of the roller. On the left hand, is the work of a single roller, on the right, is the image of a fleet. With just one machine on-site, both sides must be equal.

Compaction of soil in the base course

Picture 1 Picture 2

The next task for the roller was the compaction of soil in the sub-base. On the screen in picture 1 and picture 2, the ICVs (Intelligent Compaction Values) determined from the MOBA system can be seen on the left side. Red indicates that the compaction values are higher than needed, blue color means that the values are lower than the required values, and green stands for target values achieved.

On the right in picture 1, the compaction progress is shown. In this case, most of the values are grey. This means that only one compaction pass with vibration was made. However, there are also spots with more passes, which can be seen as a color change to magenta. It indicates that the compaction value is less than in the previous pass. Green indicates values unchanged and blue indicates values are increasing.

In our case, the conclusion is to stop compaction with vibration, as the compaction is not increasing. This decision saves money and time and reduces wear and tear on the roller. Getting the data of the full recording and analyses, the number of passes with vibration is counted and displayed in a separate view. (Picture 2 on the right)

The use of the MOBA Compaction Assistant on this site shows the enormous potential for savings in time and money for contractors with compaction and density control support.