Can anyone has gone through some research paper or personal experience regarding study of elevated temperature performance of different concretes.
I am looking for concrete with normal weight that does not lose residual strength up to 500oC
Dear Wallison Medeiros
I agree with Mr. Alex Reggiani
Best regards
Dear Wallison,
I think that what you are asking can’t be obtained using Portland cement concrete. If you know hydration process , you already have the answer to your doubt. Spallation process starts when OH groups of hydrate minerals (inside hardened concrete) increasing temperature will boil and when completely gas they expand . This phenomenon starts creating structural problems because destroys the minerals from inside . After 300°C maximum concrete explodes . You can retard this using lightweight aggregates , polypropylene fibers and foaming agents that increase molecular spaces between aggregates and air content. With higher porosity you can resist till about 450-500°C if the recipe is well balanced, but I don’t think more, using still lightweight concrete. Other problem that happens on traditional concrete comes from quality of aggregate, calcium carbonate isn’t the best.
Only with other type of technology, for example Geopolymer binders , not Alkali activated materials that are similar to Portland (still hydraulic ), you can pass easily 1200°C , maintaining enough strength.
This is my experience of course.
Best regards
Alex Reggiani
Dear Wallison,
please see this review paper, maybe it will be helpful.
https://ijret.org/volumes/2013v02/i08/IJRET20130208050.pdf
Thanks
Alex Reggiani , Alyaa Al-Attar , Zuhair Al-Jaberi Thank you for your valuable responses.
What do you think about "residual strength"?
Residual strength is the strength after the heating. Concrete is a material composed by other materials which react differently to the heat. The aggregates expand while the paste contracts. These different behaviors cause increased cracking at themperature up to 500 ºC. Cracking is irreversible... Therefore, concrete maintains the loss of strength after cooling.
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