It is very essential to know the setting time of any type of concrete you are working on. Indeed it becomes the bare necessity to know the setting time of geopolymer concrete because of its diversifying nature in accordance to its mix proportions and material used. I want to know the test procedure to check the setting time (initial and final) of geopolymer concrete. Are there any specifications or codes available for this test? The setting time of geopolymer concrete and paste are same or they differ? If they differ then how to check the setting time of both the paste and concrete?
Vicat needle testing often can be conducted to investigate the initial and final setting time of geopolymer mortar or concrete according to ASTM Standard C191 for Portland cement paste with some modification.
You can benefit from the following
Djwantoro Hardjito, Chua Chung Cheak & Carrie Ho Lee Ing " Strength and Setting Times of Low Calcium Fly Ash-based Geopolymer Mortar " Modern Applied Science, Vol. 2, No. 4 ,2008 https://pdfs.semanticscholar.org/1dd8/52e2be6d2a91ee5be93195a0a64a53c02966.pdf
B. Sri Umniati, Puput Risdanareni, and Fahmi Tarmizi Zulfikar Zein " Workability enhancement of geopolymer concrete through the use of retarder" AIP Conference Proceedings 1887, 020033 (2017); doi: 10.1063/1.5003516 (https://aip.scitation.org/doi/pdf/10.1063/1.5003516)
Vicat needle testing often can be conducted to investigate the initial and final setting time of geopolymer mortar or concrete according to ASTM Standard C191 for Portland cement paste with some modification.
You can benefit from the following
Djwantoro Hardjito, Chua Chung Cheak & Carrie Ho Lee Ing " Strength and Setting Times of Low Calcium Fly Ash-based Geopolymer Mortar " Modern Applied Science, Vol. 2, No. 4 ,2008 https://pdfs.semanticscholar.org/1dd8/52e2be6d2a91ee5be93195a0a64a53c02966.pdf
B. Sri Umniati, Puput Risdanareni, and Fahmi Tarmizi Zulfikar Zein " Workability enhancement of geopolymer concrete through the use of retarder" AIP Conference Proceedings 1887, 020033 (2017); doi: 10.1063/1.5003516 (https://aip.scitation.org/doi/pdf/10.1063/1.5003516)
At this point it will be difficult to find codes related to alkaline cements; it is a subject that still requires a lot of work worldwide from academy and industry.
The presence of aggregates most probably induces a change in the setting time of any alkali activated binder, due to:
--The aggregates offer an additional surface for heterogeneous nucleation. -- The water absorption of the aggregates might also change the overall chemistry of the alkaline solution and have an effect on the reactions
-- The possible reactivity of the aggregates might also change the chemistry of the activators since the early stages
I believe it is possible to adapt procedures used for Portland cement pastes, mortars and concretes for the purpose of measuring the setting time
Thank you sir @ J Ivan Escalante-Garcia. Yah, I have already planed to do so, test the setting time by vicat's apparatus (cement paste) and by penetration registration test (concrete). I wanted to know if anyone already tested the setting time of geopolymer concrete & paste and the relevancy of the results.
Thank you again.
The setting time will be higly effected by the Aluminosilicate source that you used to prepare the Geopolymer cement. In another word, if the Aluminum content of the aluminousilicate source is high this will result in shorter sitting time. Therefore, you could compare between the Al/ SiO2 ratio in your Geopolyme cement that you prepared to the Al/SiO2 for different types of Portland cement available in market and you could get an idea when your Geopolymer concrete will set!
I hope this make sense!!
Let us know what you found because it is interesting question!!
The ultrasonic reflexion measurements permit a continuous evaluation of setting time and strength during the time. This technique is using on cement pastes from casting to the days necessary. I think is a good option for analyzing geopolymers.
You can refer to the following
Article On the Relation of Setting and Early-Age Strength Developmen...
I'm currently working on the calculation of the setting time of slag based and fly ash based geopolymer concrete and we are applying the vicat needle testing as we did not find any specific test for geopolymer concrete.
Thank you
Please let us know if you have reached to some results, we would like to apply these results further in a metakaolin geopolymer paste we are using for our research
Thank you Dear eminent researcher for the valuable suggestions and ideas. Anass Harmal Muhammad S. Elfeky Omar Ojeda-Farías Mahmoud A. Mahrous
Dear Anass Harmal , yes I have tested the setting time of the geopolymer paste by vicate's apparatus. I have given an update regarding this. please find here-https://www.researchgate.net/project/Geopolymer-concrete-14
Thank You
Regards
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