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Asked a question 2 years ago

A question for those experts in concrete: I am a figurative sculptor and am exploring alternatives to outdoor sculptures that are created in mediums other than bronze. (so my clients have more of a choice) I am currently experimenting with a life-size full figure sculpture that has been sectioned and is fired to cone 6 (high fired) in my kiln. These sections will be glued together, void filled and will also have a steel armature inside the sculpture. One the sections are all assembled, I plan to use portland cement with a polymer additive for strength to 'chase' the seams and blend them together. The seams will be no thicker than 1/4 to 1/2 inch thick at the most, and most of it will be feathered onto the fired clay to blend the seams. After this I will apply Lastiseal (sealer for brick and concrete) and they suggest that if applying over concrete to wait 28 days. My question: if the concrete I am using is such a thin application do I still have to wait that long before applying the sealer? How long should I wait? Thank you.

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Fasi Ur Rahman
Author at The Constructor

Hello Tracy,
Thanks for asking your doubts on the curing time of cement on our community platform.

Portland cement takes 28days to achieve 99% of the desired strength regardless of the work nature and application thickness.
Applying the sealant before 28days on the cement layer will retard the complete hydration of cement by which it gains cement. This can form a weak section in your sculpture, which eventually could spall.
However, using rapid hardening cement instead of conventional portland cement and accelerated curing methods, the cement layer can achieve its full strength in a short duration.

To know about rapid hardening cement, click the article link given below:

To know about how to speed up the curing process, click the article link given below: