| Popis: |
Concrete pavements still represent a wide range of existing infrastructure. In particular, for external parking lots. The concrete pavement in the present study was placed directly on a natural ground without steel rebar or nets, without separation layer against water upward movement and with no superficial abrasion coating. The structure was exposed to an alpine clima. The microstructure and several properties of the pavement were characterized, such as density, compression strength, porosity, and water permeability. After six years, the first damage appeared and the surface layer was restored by applying a 10 mm thick mortar. Cracks were formed due to the plastic shrinkage and hygrometric inadequate post-treatment, as well as differential ground subsidence. This latter was promoted by the too high presence of fine aggregate components, which induced a compaction problem. In addition, disgregation in an advanced stage was observed. Especially along the contraction junctions, because of a too early fresh mortar cutting. Freeze/thaw cycles in the presence of deicing salts, as well as vehicles loads, also increased the deterioration. Mortar detachment from the underground concrete was due to the insufficient surface preparation, lack of adhesion and no mechanical treatment, shrinkage tension, low direct tension of the mortar and general concrete low quality. Mortar spalling was also caused by the freeze/thaw cycles in the presence of deicing salts, in particular along junctions, that were cut only on a superficial level within the mortar layer and not in depth. |
