As a ready mix supplier I can say that we regularly provide slag mixes with 30-50% replacement even in cooler months. Understanding the proper use of admixtures can assist in initial set times and ultimate strengths. I’d recommend meeting with the ready mix supplier and contractor to discuss options. Many times it is just that the contractor is in an older mind set of “that’s the way we’ve always done it” and they haven’t necessarily kept up with the advancements in admixtures.
3 Likes