Q.: We're placing our first bridge deck with shrinkage-compensating concrete using Type K expansive cement. We normally use a crane and bucket for bridge decks but wonder if this is the best placement method for shrinkage-compensating concrete.
A.: Concrete made with Type K cement requires more water than concrete made with normal cement, because a lot of water is consumed in forming the expansive product. Even with more mixing water, the concrete usually stiffens rapidly and thus is workable for a shorter period. Instead of wasting part of that shortened workability window on placement, you need to conserve it for the required consolidation and finishing procedures. Thus, we recommend pumping the concrete because it's a faster placement method.