Trade Journals for the Concrete Industry

The focus of this paper has been on studying the behavior of prefabricated elements bonded with three types of adhesives. Two mortars classified as C2S1 (deformable mortar, according to NF European standard EN 12004) and reactive adhesives based on mono-component hybrid polyurethane polymerizing under the influence of humidity were studied. The test runs showed that only polyurethane based adhesives are well adapted to their task and allow for a free movement of bonded products. The movements observed correspond, in practice, to the intrinsic shrinkage of concrete and/or to movement patterns caused by thermal effects. When these deformations are obstructed, internal stresses develop which may then generate transverse cracks once the concrete’s tensile strength level is reached. With mortars, on the other hand, free movement is usually obstructed because of the mortar’s rigidity. The advantage of reactive adhesives with regard to mortars is an increase in deformability on account of their intrinsic ductile behavior.