@Gary Regarding Blood in concrete mixes, its nothing nefarious, it's been used since roman times, usually animal blood (and even some human, if you didn't like someone) It provides unique properties as an admix material, similar to milk and hair (animal and human). For more info see Geopolymer research and Roman concrete studies. All the best F_Ree. PS: I've used it in research it works very well and this patent nonsense is BS, been around for literally ages, great for really old historical houses. Once the blood is mixed the caustics in the mix make it inert and safe.
