Fully demountable column base connections for reinforced CDW-based geopolymer concrete members

CDW-based concrete requires alkali-activators to generate geopolymerization process. These alkali-activators are difficult to be handled at the construction site and one of the rational ways to built reinforced geopolymer structures is the prefabricated construction. The connection of the precast structures is the most vulnerable component under the effect of seismic actions. Proper detailing and design of connections are crucial for sufficiently-ductile performance under seismic loading. Additionally, to achieve the disassembling and reusing of structural members, a demountable connection, i.e., dry connection, should be used instead of a wet connection. In this study, four novel fully-demountable connections for reinforced construction and demolition waste-based (CDW) geopolymer concrete members are developed. Seismic performances of these different demountable connections and one reference monolithic connections are experimentally investigated. The connections are subjected to reversed cyclic lateral displacements under constant axial loading. Comparisons are made referring to observed damage patterns, connection strengths, moment-curvature relations, initial stiffnesses, plastic hinge lengths, and energy dissipation characteristics of the proposed demountable connections and the monolithic connection. The results of the experimental study indicate that one proposed demountable connection exhibited larger lateral capacity and better seismic performance than its monolithic counterpart, whereas the other three proposals showed less performance than the monolithic counterpart.