There is lack of ships for these two materials.
I know that one ship for cement is already available - but one more would be greeted. I think that it could be prepared from ships for else bulk cargo.
And ship for concrete is missing fully. One such ship would be greeted too. I think that until creation of fully new one it may be prepared by repainting and mostly recoding of ship for wood or steel. I think that those two ships would be quite good source for temporar solution of lack of ships for concrete.