Accessibility is becoming increasingly important for public spaces as part of inclusion efforts. Historic market squares and streets, which are visually impressive due to their cobbled appearance, are a major challenge for urban planners and mainte-nance people. On the one hand, you want to preserve the historical character, but on the other hand, you also want to make them safely accessible for people with disabilities. 

In close cooperation, the producer of mineral hard materials Korodur, and the construction machinery manufacturer Schwamborn, have now developed a practical and cost effective solution that also meets the requirements of DIN standard 18040-3. This is similar to an ISO standard to provide access free to public spaces for people with disabilities. 

This advance has been made possible by the production of suitable building materials that are easier to work with, and whose load bearing capacity is constantly being increased. However, modern construction machinery is needed for carrying out heavy work precisely without damaging the historic building materials. “In this respect, the cooperation with Korodur was an absolutely obvious idea if you want to develop new, promising and, above all, holistic solutions,” says Schwamborn’s product manager Florian Schwamborn. 

Jens Sackmann, who is responsible for paving joint sealing in northern Germany for Korodur, adds: “When it comes to accessibility, what use is the best performing jointing material such as our ‘Mortar Mix’ product if we can’t get rid of the large unevenness with it? We are therefore very proud that we were able to develop a really convincing solution with the help of the Schwamborn BEF 400RC that is significantly more cost effective than new road construction.”

Large and deep joints, as well as paving stones that protrude to different heights, are the biggest problem for accessibility, as they are simply not safe, being tripping hazards for anyone who has a mobility disability. They also generate noise when they are driven over. For this reason, the joints must first be cleaned and rinsed, refilled and then the surface levelled. Depending on additional work steps, even the natural historical appearance can be preserved.

The work steps in detail

1. Preparation of the surface

To prepare the surface, the joints and surface should be cleaned out to a depth of at least 40mm using a high pressure cleaner.

2. Filling the joints

The joints and surfaces are then treated with a retarder and then filled with the Korodur product ‘Mortar Mix’.

3 Levelling the surface

Depending on the height differences of the paving stones, the surface can now be levelled to a depth of between 5mm and 20mm. This is done with the innovative Schwamborn BEF 400RC milling machine, which can be equipped not only with conventional milling cutters, but also with closely mounted diamond cutting discs. The paved surface is therefore not milled in the classic sense but cut flat. Any protrusions are levelled with a concrete grinding machine such as the DSM 530S equipped with PCD grinding diamonds. In principle, this achieves accessibility in accordance with the DIN standard.

4 Finishing the surface

Various options are now available for finishing the surface, depending on the client’s requirements, and the desired appearance. The purely cut floor has the advantage that the fine grooves provide increased slip resistance. If the floor is additionally grinded after cutting, a more homogeneous surface is achieved. 

5 Restoring the historical appearance

Naturstein Wolf, a company that specialises in natural stone processing from Lübeck, Germany, was involved in restoring the historical appearance of a cobbled roadway. Following thermal treatment, the levelled and grinded surface was treated with a flame emitter to restore the historic appearance. This also increased the slip resistance of the levelled paved surface. “We were very impressed by the result,” says Florian Schwamborn of Naturstein Wolf. “As a manageable number of work steps resulted in absolutely barrier free surfaces that even retained their original appearance.” Jens Sackmann from Korodur concludes, “A practicable and comparatively cost effective solution to a classic dilemma for accessibility in public spaces has now been developed.”