What's in these mortars that makes them set up quickly?I know that some will contain calcium aluminate or similar, that reduces the setting time to a couple of hours or so, but what about the mortars that go off in a few minutes. I see resin mentioned sometimes, but what is it and how does it work?
Postmix and other rapid-setting mortars
Jan 06, 2022
Last reply: 4 years ago
2 Replies
I?ve always assumed it is based on a different cement.
There is one based on calcium sulphuraluminate (I think that is the correct name) which sets rapidly, doesn?t shrink or crack.
Additives slow Portland based mixes but only marginally. To get a step change, you need to change the mix.
A d-i-y is to add soda -- sodium carbonate. Never tried it, but it's supposed to speed the setting. Alternative would be sodium silicate.
Don't know how they do their thing...
Thomas Prufer
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