Alkali activated composite binders of waste silica soda lime glass and blast furnace slag: Strength as a function of the composition

Composite binders of urban waste glass/blastfurnace slag activated by NaOH and NaOH/Na2CO3 were studied using statistical methods (Taguchi); the factors were: %glass, curing temperature, %Na2O and ratio of alkalis; the compressive strength was the response variable. The optimal levels at 28 days were %0glass-60 degrees C-6%Na2O using 2Na(2)CO(3)/NaOH; after 90 days these changed to 100%glass-60 degrees C-10%Na2O using Na2CO3. The microstructure and composition of the hydration products varied depending on the glass content. The reaction mechanism was mainly of dissolution-precipitation of reaction products, in some cases rims of reaction products formed around the slag particles. The confirmation experiments matched the statistical predictions. (C) 2016 Elsevier Ltd. All rights reserved.