ABSTRACT
In the last few years at several airports, but also at industrial areas cracking in concrete gutters was detected by video-inspection. This has mainly been observed where large concrete fields (about 60 to 100 m in length) were located next to these drainage lines. Due to such damages the operability of these gutters is severely impaired. In most cases such effects appeared when the pavement concrete was cast in the cold season, i.e. at lower temperatures. Due to high temperature differences the pavement may considerably expand during the following hot summer periods. Expansion is only possible in direction of the joints next to the concrete gutters. Accordingly, the pavement expansion is concentrated in these areas. On the other hand bituminous soft boards are usually integrated in these joints as filling material. However, these soft boards can be deformed only by about 15% without causing high reaction forces. In consequence this means, when the joint filling material is pressed to a much higher degree by the adjacent pavements, horizontal stresses up to 5 to 10 MPa are activated. However, the concrete gutters are normally not designed and constructed for such horizontal loads. The result is an extensive cracking in the interior of the gutters and finally their complete destruction. In extensive programs—in situ as well as in the lab—the properties of alternative filling materials for such expansion joints were investigated. Especially the deformation behavior (stiffness as well as the re-deforming capability) was studied for various materials. The best results were shown by polyethylene-foams. In this case only low reaction forces are caused by the expansion of the adjacent concrete pavement and hence damaging of the concrete gutter can be prevented. At the same time such materials show a high elasticity, i.e. the joints are completely refilled and sealed during the re-deformation (contraction) of the concrete slab in colder seasons.
