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

• Published in: Construction & building materials 2016-08, Vol.119, p.119-129
• Main Authors: Martinez-Lopez, Ricardo, Ivan Escalante-Garcia, J.
• Format: Article
• Language: English
• Subjects: Alkali activated binders; Alternative cements; Analysis; Blast furnace slag; Cement; Chemical properties; Mechanical properties; Silica; Slag; Strength; Waste glass
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2016.05.064

•Composite binders of urban waste glass and blast furnace slag were studied.•The Taguchi method was useful to optimize the formulation of the composites.•The addition of Na2CO3 promoted high dissolution of glass particles.•The reaction products were C–S–H and silica gel.•Glass is a promising addition to alkaline slag cements. 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 28days were %0glass-60°C-6%Na2O using 2Na2CO3/NaOH; after 90days these changed to 100%glass-60°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.