Behaviour of cracked grout-bodies of micropiles with different corrosion protection measures

Tensile elements are used for a variety of geotechnical tasks to transfer loads into the subsoil. Together with the requirements regarding the load-bearing capacity (ULS) and serviceability (SLS), additional issues, such as their durability have to be considered in the design. Due to subsoil properties as well as ground water, insufficient corrosion protection can lead to massive corrosion damage of tensile elements. In addition to the effects on the service life, such damage can also have an influence on the serviceability and subsequently on the load-bearing capacity. Therefore, different corrosion protection systems are used depending on subsoil conditions, the planned service life and external influences. In this paper, investigations are presented which deal with the issue of corrosion due to cracking of the grout-body of micropiles. In two tests, samples with different corrosion protection measures were subjected to tensile stresses. In addition to a visual recording of the crack patterns, computer tomographic scans were carried out. Therefore, additionally to the verification of the crack formation, these investigations allowed to evaluate the “interior” of the grout- body. Thus, the studies provide information on the function of different corrosion protection measures.