Calcuim In Concrete

[00si2]

I'm having my concrete poured this weekend and am looking for some info about adding calcium to the mix. My contractor wants to use 1%. He would like to use it to speed up the set time so he can get a good finish on it. The temps will be in the mid 40's for a high. What are the cons with using calcium? From what i have found it slightly reduces the cured strength and it can cause steel reinforcing to rust when used in a higher percentage. Is there anything else i am missing? Is it going to cause any problems with an epoxy finish later down the road?

 

[00si2]

Anyone......?

 

[Hmrhead]

Would suggest contacting the cement yard where the contractor is getting your concrete. Ask if they have an alcohol based accelerator instead of the calcium chloride. If they do not, ask how much you would need for your job and if they would be willing to have their drive add it onsite in the truck. You should be able to find it at a brick distributator. They may have to order it so plan ahead. Most masons like it but opt for CC due to expense. It is more expensive but does not leave extra soluable salts behind in the concrete. Reduces the possibility of efflorescence. The calcium chloride may reduce cured strength a bit but not enough that you would notice unless you are really loading the floor with heavy traffic. As long as you have a vapor barrier under the pour rusting of the rerod would be minimal. Rusting would only take place as long as there is moisture in the concrete. Once cured only way for oxidation to occur would be from moisture migrating up from underneath. Hope this helps.