How do they make quick setting concrete for sea defences in the UK?

Question

Been on holiday recently to a UK resort (W/S/Mare) they are building new sea defences, foundations have been dug quite deep and the concrete lorries were pouring their loads within a short space of time say 1 hour work men were removing plywood shuttering away from the concrete base as it looked set.

How do they make concrete set so quick considering the tide was starting to come in.

Answer 1

ONE secret of quick setting cement is that it is ground VERY finely, so that the particles have more surface area.  BTW, those were "Concrete" lorries (or mixers here in the U.S.), because cement is just the "glue" that holds it all together.

There are also MANY additives that can be added for strength, from micro-fibers to catalysts.  And, while quick setting concrete holds it form quickly, it still takes years for it to cure, entirely.  The Hoover Dam, built in the late-20's is STILL hardening, today.  

Answer 2

They use a SR cement    Solvite Resistance  this is a liquid they add to the cement  when  it leaves the kiln before being crushed to powder,it is stored away from other cement.