Surfactant-induced growth of a calcium hydroxide coating at the concrete surface
Résumé
In addition to its remarkable mechanical properties, high-performance concrete (HPC) also exhibits a very smooth surface with low porosity, which makes it particularly suitable for esthetic applications. Unfortunately, the constant environmental aggressions to which the urban buildings are exposed (organic or inorganic particles, algae, micro-organisms, staining from various sources) are a threat to their structural and esthetic durability. This article proposes an innovative method to protect HPC surfaces based on Ca(OH)2 growth at the fresh concrete/formwork interface. With the adequate surfactants used as demolding agents, it is possible to grow a continuous layer of Ca(OH)2 at the concrete surface which closes the porosity, reduces the water uptake, and gives the surface super-hydrophilic properties, facilitating self-cleaning mechanisms.