Well yeah, got to consider biodegradable ingredients these days...........
These guys are full of beans.
Portland cement is produced by heating massive amounts of raw material into something called clink, this clink undergoes a chemical reaction which gives it binding powers.
It’s crushed into a fine powder and that is Portland cement that when combined with water and aggregate form concrete.
You could never get seashells and bones in the massive amounts necessary to produce enough clink to meet the demand for concrete.
Modern cement plants have been steadily reducing the amount of energy they use to produce clink as new plants come online using preheat and other methods.
These guys are just hunting for Grant money, their ideas are impractical.