This study evaluates four groups of non-traditional aluminosilicate industrial coal byproducts and natural pozzolans-ground bottom ashes(GBAs),low-purity calcined clays(CCs),volcanic ashes(VAs),and ffllfluidized bed c...This study evaluates four groups of non-traditional aluminosilicate industrial coal byproducts and natural pozzolans-ground bottom ashes(GBAs),low-purity calcined clays(CCs),volcanic ashes(VAs),and ffllfluidized bed combustion ashes(FBCAs)-as potential precursors for alkali-activated binders.Each group was activated using a mixture of sodium silicate and sodium hydroxide solution under optimized solution parameters.Their reaction behavior,pore solution changes,phase assemblage,and composition were analyzed using various material characterization tools.Results indicate that the reaction rate and total heat are similar to those of conventional ffllfly ash precursors,with total heat release 38%–82%lower than that of Portland cement.Pore solution analyses reveal the formation of typical alkali-activated gel phases,and nuclear magnetic resonance(NMR)revealed calcium sodium aluminosilicate hydrates with aluminum/silicon(Al/Si)ranging 0.07–0.36.A novel reactivity index was proposed using Al-NMR.CCs and GBAs exhibited superior performance compared to other two materials used.展开更多
基金financial support from the Federal Highway Administration,USA(693JJ31950019)to a team of researchers at Purdue University,The Pennsylvania State University,and Clarkson University。
文摘This study evaluates four groups of non-traditional aluminosilicate industrial coal byproducts and natural pozzolans-ground bottom ashes(GBAs),low-purity calcined clays(CCs),volcanic ashes(VAs),and ffllfluidized bed combustion ashes(FBCAs)-as potential precursors for alkali-activated binders.Each group was activated using a mixture of sodium silicate and sodium hydroxide solution under optimized solution parameters.Their reaction behavior,pore solution changes,phase assemblage,and composition were analyzed using various material characterization tools.Results indicate that the reaction rate and total heat are similar to those of conventional ffllfly ash precursors,with total heat release 38%–82%lower than that of Portland cement.Pore solution analyses reveal the formation of typical alkali-activated gel phases,and nuclear magnetic resonance(NMR)revealed calcium sodium aluminosilicate hydrates with aluminum/silicon(Al/Si)ranging 0.07–0.36.A novel reactivity index was proposed using Al-NMR.CCs and GBAs exhibited superior performance compared to other two materials used.
