Akademik Veri Yönetim Sistemi
Proceedings of theAnnual Conference of the Canadian Society of Civil Engineering 2022, Whistler, Kanada, 25 - 28 Mayıs 2022, cilt.359, ss.799-816
The re-utilization of construction and demolition wastes (CDWs) in the emerging geopolymer technology has been recognized as an environmentally friendly solution for tackling the ecological challenges caused by the increased landfilling of CDWs and sustainability issues of Portland Cement (PC) production. Geopolymers are synthesized as a result of intricate chemical interactions between aluminosilicate-based precursors and highly alkaline solutions resulting in the production of amorphous inorganic geopolymers possessing three-dimensional cross-linked networks of Si–O–Al and Si–O–Si bonds. The aim of this study is to investigate the effect of incorporating different types of aggregates including recycled concrete aggregates sand (RAS), silica sand (SS) and natural sand (NS) on the rheological properties of geopolymer mortars (GPM) prepared from CDW-materials comprising a combined powder mixture of recycled clay brick (RCB), recycled ceramic tile (RCT) and recycled concrete (RCW) wastes as silico-aluminate binders. Yield stress, viscosity and shear stress were tested at 100% of RAS, SS and NS contents in GPMs prepared with sodium silicate and sodium hydroxide solutions as alkaline reagents and predefined chemical design factors of SiO2/Al2O3, Na2O/SiO2, H2O/Na2O and water-to-binder (W/B) ratios. The correlation between the rheological properties of GPMs and the predefined design parameters was considered. The highest yield stress and viscosity were obtained at medium SiO2/Al2O3 molar ratio of 5.6 for all three GPM systems, while further increase in silicate species caused reduced stresses and viscosities. Comparable shear thinning behavior, higher viscosity and accelerated polycondensation properties were observed with increased RAS amounts compared to SS and NS.