DENSOLASTIC^®-EM / EM-G elastomer mortar

When fastening covers to shafts, a cement-bonded mortar is generally used to form the uppermost joint. This gives a firm but rigid bond between the shaft and the shaft cover.

If this shaft then comes under stress from the cars and trucks passing over it, all the resulting forces are directed via the rigid mortar joint straight into the shaft beneath. The passing traffic creates a dynamic load that stresses the construction in a different way from a static load resting on the shaft cover. This rather more intermittent stress cannot be resiliently absorbed by the rigid mortar; the mortared joint, as the weakest point in the vicinity of the stress and depending on the type and intensity of the passing traffic, will become brittle. As the mortar breaks away, the cover of the shaft gradually sinks below the surrounding road level. This leads to the tires of vehicles striking the shaft cover from above as they pass, which speeds up the decay of the mortared joint. In particular, the rapid succession of the tires of a convoy of trucks can create a great deal of damage very quickly.

If the cement mortar joint is replaced by a shock-absorbent synthetic material, for example an elastomer mortar, the stress described above can to a large extent be absorbed directly under the place where it has been created, and before it passes to the shaft construction below. Such a joint would not crumble under the ongoing stress and would keep its shape; the shaft cover would not sink below road level.