BINDING BEHAVIOUR AND OF REACTION PRODUCTS IN BINDER GEOPOLIMER PASTES

Abstract

Pastes of granulated blast furnace slag and zeolitic tuffat different mass ratios were activated with alkali solution (sodium silicate) at lower alkalinity with modulus Ms= %SiO2 /%Na2O = 2 . The heavy metals contained in slag are immobilized into geopolymer matrix of composite material, so obtained and thus significantly reduces the risk of environment contamination. Granulated lead furnace slag, zeolitic tuff, sodium hydroxide and sodium silicate were used as starting materials. Binder of 50% slag developed the highest among all slag based geopolymeric pastes whose compressive strength are 42 MPa. As a result, the cement containing 50% slag that is synthesized at curing (600 C for 12 h), exhibited higher mechanical strength and SEM observation shows that it is possible to have localized of (C-S-H) geopolymeric gel. Pastes of granulated blast furnace slag (GBFS) and zeolitic tuff(BZ) in mixture developed stable microstructures with high compressive strengths, and the toxic metals (Pb, Zn, Cd) from slag were locked into the geopolymeric matrix.