title: The Performance of Geopolymers Activated by Sodium Hydroxide.
abstract: Geopolymers, a group of promising environmentally friendly materials that can work as cement substitutes, should be fabricated from SiO2-Al2O3-CaO mixtures containing large amounts of amorphous phases to ensure optimal chemical and physical properties. In this study, it was shown that geopolymers with enhanced mechanical strengths, as high as 115 MPa, could be obtained from perfectly amorphous slag from spent catalyst (SSC) discharged during automobile catalyst recycling. Geopolymer processing involved alkali-activation using a 16 M NaOH solution of pH13. The varying SSC grain size was the main experimental factor of interest, in combination with curing temperature and aging time. Variations in the mechanical strengths of the resulting geopolymers are explained by the occurrence of 10-50 nm-sized crystals and the presence of voids and pores dozens to hundreds of micrometers in size.
authors.forename: Hyeontaek
authors.initials: H
authors.lastname: Hong
authors.forename: Seunggu
authors.initials: S
authors.lastname: Kang
mesh_terms: D000268:Adhesiveness; D000538:Aluminum Silicates / Q000737:chemistry*; D019245:Compressive Strength; D003252:Construction Materials / Q000032:analysis*; D055772:Green Chemistry Technology / Q000379:methods*; D006244:Hardness; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012972:Sodium Hydroxide / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D014867:Water; D012972:Sodium Hydroxide