From many literature studies, it is mentioned ss/sh ratio is 2.5 as optimum. If the ratio increase the strength decrease due to various changes in polymerisation
Kiran Kumar Poloju If I have understood correctly from your question:
When constructing geoplymer cement, all the calculations must be taken into account. for Instance, higher molarity may result in leaching of free cations (e.g. Na+) which will be observable on the surface of the specimens. On the other hand if the molarity of the activator/hardeners are lower than required, the polycondensation may remain incomplete and may result in low strength and durability. Therefore, the aim should be to achieve a chemically stable structure (Na/Al=1) and the ratios should be chosen accordingly.
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Article Quarry Waste as Precursors in Geopolymers for Civil Engineer...
Within the range of SS/SH mentioned, depending on the type of the base materials (SiO2, AL2O3, CaO quantities), an increase of the molarity up to 10-14 molar will result into an increase of the compressive strength. Beyond this range, the mix will become supersaturated by the cations of Na which in turns decrease the quality of the C-S-H and the polycondensed 3D netwroks formed in the AAS or geopolymer.
High molarity reduces workability as observed from the various tests conducted by me with molarity ranging from 6 M to 14 M. Optimum strength molarity of 12 M resulted in maximum strength attainment. However, in my case it was no-sodium silicate alkali activator.
In my opinion, there are various other parameters from which we derive a conclusion towards the strength development of geopolymer concrete.
However, to be specific, it all depends upon the molar ratio, specific gravity, and %solid concentration of alkaline solution - from which, we must determine our optimum ratio after rigorous experimentations.
Please, investigate with different molarities of your grade of NaOH and check.
Thank you.
Best wishes
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