Hi,

I'm interested in the problem of ettringite formation on Calcium Sulphate floor screeds when in contact with cement based tile adhesives. I work for a GGBS, Ground Granulate Blastfurnace Slag, producer in Ireland and our product works exceptionally well in mitigating sulphate attack (ettringite formation being one) in concrete. I'm wondering has anybody come across GGBS in cement based tile adhesives, I believe our product could work very well in this area any may possibly remove the need for a sealer/primer when using calcium sulphate floor screeds and cement based tile adhesives and possibly open up the use of calcium sulphate screeds in wet rooms.

Regards,
John

way over my head im afraid

Thanks for the welcome Mike. It started way over my head but its coming closer to my horizon slowly but surely.

welcome John, one of our members is an expert in the field of anhydrite screeds (Ajax123). I'm sure he could advise you on this

Hello and welcome..

Hi and welcome

John

Hi John

One of the issues I have come across when GGBS and PFA are used in contact with Calcium Sulphate is polysulphide attack which disrupts the screed expansively and very aggressively. It is quite a rare reaction and where I have seen it it has been associated with concrete blocks in block and beam floor systems where there is no divorcement of the screed from the blocks.
If you are serious about looking at this PM me and I will be abe to discuss it with you. I was on a site today where there has been an issue with the adhesive and I felt that there might have been GGBS in the adhesive but I was unable to ascertain the brand or manufacturer.

Thanks all, seems I've found my man. PM sent Ajax123. I'll revert to the forum with my findings.

Johnerr - I did not get your PM - you can try again or send me an e-mail to Alan.Jackson@Lafarge.com i you like.