I've run into Siporex panels, which are a type of low density concrete per-fabricated panels. When these panels become water logged their tensile strength drops

I've run into Siporex panels, which are a type of low density concrete per-fabricated panels. When these panels become water logged their tensile strength drops off quite a bit more than conventional concrete panels. The climate in which these panels are to be used probably plays a significant factor in specifying their use.