I have alot of experience with 40% slag replacement, there is no difficulty in replacing the portland cement, provided you use a mid range plasticer to reduce your overall water content. A mid range plasticer from Grace Chemicals or Sika, will give you a reduction of 25/30 litres or kg of water...
Ireland we have successfully used up to 40% replacement, and have achieved a significent increase in 28 day strength. I would strongly recommend a mid range admixture, reducing w/c is essential. One of the main problems with all blended cements is formwork stripping times. We are currently...
