You can add 5 to 10 % mass of powder of bauxite to your formulation.

You can add 5 to 10 % mass of powder of bauxite to your formulation.

i added silica hume 2.5%, gypsum 5% and Superpalasticiser Complast SP 430 individually and as combinations.. Even then, the workability is very low and setting time is about 5 to 10 min. 

 Dear Ponnada,

Why don't you change the ratio of the components? The bindig mechanism of your geopolymer could be different as in normal concrete, so the typical retarders, etc. used in concrete technology probably not efficient (we don't know your recipes - the mix design).

Maybe the decrease of the alkali compound will help.

Best regards,

Katalin

Dear Katalin,

The higher the molarity of alkali activators, the higher is the strength and lower is the workability. Hence decrease of alkali compund cannot help.

Ideally, i need a chemical that can retard or delay the polymerisation of GGBS and Alkali for a few minutes.  May be an opposite to catalyst. I am not very good at Chemistry, so may be unable express my requirement.

Regards

Markandeya 

Type of Fly ash and its chemical composition plays an important role in determining the setting time of the geopolymer concrete. Type F fly ashes can be used to avoid flash setting. You can go through this paper as well, 

Article Current state of k-based Geopolymer cements cured at ambient...

Dear Ponnada,

Thank you, you are right, we have experienced the same problem  with our flyash. Now we are working on the improvement of the mixtures.

Regards,

Katalin

We experienced the delaying of setting time of geopolymers using calcined oyster shell . Can you please read the paper published in Construction and Building Materials referenced as: Y.J.N. Djobo, A. Elimbi, J. Dika Manga, I.B. Djon Li Ndjock. Partial replacement of Volcanic ash by bauxite and calcined oyster ,shell in the synthesis of volcanic ash-based geopolymers, Construc. Build. Mater., 113 (2016) 673-681?

Regards

.

Did you tried reducing the temperature by adding cold water or ice? Let me know if that works

We experienced the delaying of setting time of geopolymers using calcined oyster shell . Can you please read the paper published in Construction and Building Materials referenced as: Y.J.N. Djobo, A. Elimbi, J. Dika Manga, I.B. Djon Li Ndjock. Partial replacement of Volcanic ash by bauxite and calcined oyster ,shell in the synthesis of volcanic ash-based geopolymers, Construc. Build. Mater., 113 (2016) 673-681?