Evaluations on the A12 test track

Seven months have passed since a Cedima Future Grinding surface was ground into the concrete slab on a section of the A12 motorway for test purposes. This was already reported in detail in the last issue of "Betonbohrer". The aim was to increase the grip of the surface while reducing rolling resistance, to minimise aquaplaning through optimised drainage and, last but not least, to noticeably reduce the rolling noise of the tyres. In addition, the improved properties of the road surface, measured by today's standards, were to be maintained.

Test under real conditions

For this purpose, a grooved profile with macro texture was ground into the existing concrete roadway using a patented grinding process. This method was developed at Cedima GmbH and is now to be tested under real conditions in cooperation with the "Acoustic Grinding" working group of the Road and Transport Research Association (FGSV). To assess the durability of these surfaces, the Federal Highway Research Institute (BASt) carries out long-term monitoring. The results are not expected until the coming years. After normal vehicle traffic on the busy A12 has flowed over the test area for more than half a year, the scientific evaluation has now been carried out by the BASt. For this purpose, a measurement of the noise emission was again carried out on the test track with 2 reference tires, one car and one truck tire. The result showed that there had been no increase in the emitted rolling noise. The lower value of -3 dB(A) immediately after the construction of the new surface compared to conventional roadways could be maintained. At first glance, that doesn't seem like much. However, given that a reduction in the level of 10 dB(A) corresponds to a halving of the volume in the subjective human perception, the reduction in noise emission is considerable.

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Hardly any wear

A further test was intended to provide information about the wear of the surface. For this purpose, 3D measurements, as well as texture measurements were carried out with ELATEXTUR, a special measuring device from IWS-Messtechnik. This evaluation has shown that even after seven months, there are hardly any signs of wear and tear in ongoing road traffic. In contrast to conventional processes, in which only grooves are milled into the concrete surface at a defined distance, Cedima Future Grinding also mills off the upper part of the bars between the grooves and provides them with a microstructure. During the development of the new process, it turned out that the uppermost thin layer of the concrete roadway in particular is softer and tends to wear and tear. Therefore, on roads that have been treated with conventional grinding methods, severe signs of wear and tear occur after a short time in the form of wild outbursts.

Long shelf life expected

The surfaces treated with the Cedima Future Grinding show no or very little signs of wear even after several months. This suggests that in the course of monitoring by the Federal Highway Research Institute, these road surfaces can be granted excellent durability over a long period of time in addition to the positive properties for reducing noise and aquaplaning.

Patented process

Future grinding was developed and constantly improved at Cedima GmbH over many years. In the meantime, the process has been patented and has already proven itself many times in practice. Currently, the strong floor saws of the fully hydraulic 60 series are used for use. Equipped with a grinding attachment kit, they can accommodate a 600 or 800 mm wide milling shaft, depending on the type. In the past, Cedima has already developed and built special machines on behalf of customers, which are driven by a 330 kW diesel engine and have a working width of 1250 mm. Depending on the substrate material, these machines achieve a maximum feed speed of eight to twelve meters per minute. When the tool is fully loaded, this results in an impressive 15 m² of machined area in just one minute or the size of a football field in just 8 hours. All of the machines mentioned work precisely, effectively and, thanks to the always available extraction system for the cutting sludge produced, also particularly cleanly with the Cedima Future Grinding process. Cedima will continue to drive forward the development of the Future-Grindig process in the future.

This article was first published in issue 55 of the trade magazine "DER BETONBOHRER".
Published by Fachverband Betonbohren und Sägen Deutschland e.V.