Preparation of geopolymer from fluidized bed combustion bottom ash

This study has shown that it is possible to use fluidized bed combustion bottom ash (FBC-BA) without any thermal activation as a partial- or full-replacement for kaolinitic raw material in geopolymerization. Test specimens prepared from FBC-BA have reached compressive strength of almost 50 MPa after 90 days of hardening. After 50 freeze-thaw cycles, the compressive strength of test specimens has not decrease below 80% of compressive strength of unaffected reference specimens, which represents an acceptable freeze-thaw resistance. Testing of wet-dry resistance has shown that wet-dry cycles cause an increase of the compressive strength values. Testing of acid resistance of prepared geopolymer specimens has shown that replacement of usual kaolinitic raw material by FBC-BA results in slight increase of leachability.