The materials used in this study are namely Ground Granulated Blast Furnace Slag (GGBS), High Calcium Wood Ash (HCWA) and washed river sand.
Meanwhile, HCWA is a byproduct acquired from an industrial scale fully automatic boiler unit (commercially known as Bio-Turbomaxx boiler).
The hybridization ratio begin with 100% of GGBS as the control mix and subsequently replaced by using HCWA at 10% increment interval by total binder weight.
By looking at the overall trend, the inclusion of HCWA in conjunction of with GGBS had a significant impact on the geopolymer mortar compressive strength of every mixtures as compared to the control mix (100% GGBS).
This is likely because the high alkalinity inherited from the potassium oxide content of HCWA that promotes the dissolution of alluminosilicate materials, hence, contributing to the rapid compressive strength development at early ages .
The result indicate that the w/b ratio increase with the stepped addition level of HCWA replacement.