New roofing tile with enhanced surface durability and processes for manufacturing the same

摘要

The invention provides a roofing tile comprising: (a) a substrate; and (b) a coating disposed on said substrate, said coating resulting from hydration and hardening of a mixture comprising a hydraulic binder, said hydraulic binder comprising at least 60% by weight of a source of calcium aluminate and no more than 1% by weight of sulfate. The invention also provides methods for making the tile. Durability, acid resistance and freeze-thaw resistance are enhanced due to formation of a dense layer of hydrated alumina (AH 3 ) gel that fills the pores at the surface exposed to environmental impact.