A lot of damage to concrete structures occurs as a result of cracks and cavities that allow pollutants to penetrate the structure. These damaging influences impair the function of the concrete and thereby considerably reduce the load bearing capacity of the construction work.
If construction work is designed
If a building or structure is designed and constructed with in reinforced concrete, cracks in load-bearing and non-load-bearing building components are inevitable.
The embedded reinforcement only starts to absorb tensile forces once the concrete has cracked. The architect has three design principles that give him the opportunity to prevent cracks forming, to allow the creation of smaller uncritical cracks, or to plan a few larger cracks that need to be filled retrospectively. Each design principle is carefully matched to the usage requiremetns of the structure.. Subsequent closing of cracks also requires careful planning.
In the event of unplanned cracks and their repair, the cause of the cracks is important. In addition to the material-specific parameters of the concrete, the subsequent loads, such as subsidence or changes of use, also have an impact on the formation of cracks. The condition of the crack and the crack movement is decisive for the success of the repair work.
Filling cracks aims to inhibit and prevent penetration of substances that corrode concrete and steel. If there is a repeat cause for cracks, it can be assumed that the crack will occur again, however with a non-critical crack width. Closing cracks by filling them should not be seen as a constructive intervention.
WIth structural injection, the crack edges are filled with hydraulically bound or polymer crack filling materials so that a transfer of pressure, tensile or shear forces in the building component can be recreated. This procedure can only be applied in cracks where the cause of the cracks has been removed.
In the case of partially expandable filling, the crack edges are connected elastically with an elastic polymer crack filling material. This technique is only suitable for filling cracks where the cause is not eliminated.