Investigation of novel waste glass and limestone binders using statistical methods

• Novel binders based on urban waste glass and limestone were studied.
• The Taguchi method is useful for the optimization of the experimental work.
• Statistical analysis allowed to predict and maximize the strength.
• The hydration products were amorphous C–S–H, silica gel, pirssonite and gaylussite.
• The incorporation of Na2CO3 caused a synergistic effect that increased the strength.

This paper presents a study on new alternative binders based on waste glass and limestone activated by NaOH and Na2CO3. The Taguchi method was applied, to optimize the experimental work while keeping statistical significance, considering the factors: CaO/SiO2 ratio, % Na2O and curing temperature; their effect was analyzed on the compressive strength using signal to noise ratios. The optimal conditions included CaO/SiO2 = 0.5, activated at 40 °C with 9% Na2O using Na2CO3/NaOH; the strength of the confirmation experiments agreed with the predicted values. The reaction products were: calcium silicate hydrate, a silica gel type phase, and crystalline phases like pirssonite and gaylussite.