Preparation of High Strength Geopolymer Hardened Material from Waste Concrete

Waste cement powder, which is generated after separation and recovery of aggregates from concrete waste, was attempted to reuse as a raw material of geopolymer hardened material. The geopolymer attracts attention as a new material to replace conventional cement, because the geopolymer emits less carbon dioxide compared with the conventional cement during its manufacturing process and has high resistance to acids and heat. In this study, the geopolymer hardened material was prepared from mixed powder of waste cement and granulated blast furnace slag. The prepared geopolymer hardened material had a high compressive strength over 24 N/mm2 enough to be used as construction material. When the mixing ratio of the waste cement powder and the granulated blast furnace slag was 40 : 60, the compressive strength was 76.8 N/mm2.