Workability and Strength Characteristics of Alkali-Activated Fly ASH/GGBS Concrete Activated with Neutral Grade Na₂SiO₃ for Various Binder Contents and the Ratio of the Liquid/Binder

Alkali-activated fly ash/GGBS concrete (AAFGC) is a new blended concrete that has been studied by many researchers due to its environmental advantages and better technological characteristics. However, the effect of various factors on AAFGC fresh and hardened properties has not yet been thoroughly studied. The literature mainly describes the combination of NaOH and Na2SiO3 as an activator for the AAFGC’s activation, but alkali-activated GGBS concrete (AAGC) prepared with this activator solution is less workable due to its rapid setting behaviour. In this study, AAFGC was prepared using neutral grade liquid Na2SiO3 with a SiO2/Na2O ratio of 2.92. An experimental program was performed for fly ash-GGBS combinations (100-0, 50-50, 0-100), solution/binder ratios (0.6, 0.65, 0.7) and binder contents (300, 400 and 500 kg/m3) to evaluate the workability and the compressive and tensile strength of AAFGC. The results of this study show that a water glass of 2.92 silica modulus used as an activator to prepare AAFGC under ambient curing is very useful in the construction industry.