This paper introduces an innovative approach to produce low sulfate AAC which complies with all normative requirements including environmental issues. The aim was a significant reduction of the sulfate concentration in the eluate thus matching existing and upcoming European regulations on the recyclability of demolished AAC. This goal was accomplished by eliminating the sulfate carrier and reducing the cement content by introducing calcined clay as supplementary cementitious material. Both, laboratory tests and large-scale industrial trials confirm the possibility to completely replace the sulfate carrier as well as up to 20 wt.% of the cement by calcined clay. The amount of leachable sulfate ions was reduced by up to more than 75 %. The content of crystalline tobermorite was even slightly higher in samples with calcined clay. The new environmentally friendly low sulfate AAC fulfills the mechanical properties according to the relevant European standards and is ready to be used in production.    «

This paper introduces an innovative approach to produce low sulfate AAC which complies with all normative requirements including environmental issues. The aim was a significant reduction of the sulfate concentration in the eluate thus matching existing and upcoming European regulations on the recyclability of demolished AAC. This goal was accomplished by eliminating the sulfate carrier and reducing the cement content by introducing calcined clay as supplementary cementitious material. Both, labo...    »