Q.: How does the fineness of cement affect the quality of concrete? If the fineness is high, what procedures can be followed to maintain quality in the product?

A.: The fineness of cement usually affects the rate at which cement gains strength. It may also have a minor effect on workability but probably not much.

If you took a cement and ground part of it to a greater fineness the finer portion would produce higher early strength than the other portion. Fineness cannot by itself, however, be taken as an index of strength because there are so many other things that affect a cement's strength-producing potential. One manufacturer could readily produce a coarse cement which had a more rapid rate of strength gain than another manufacturer's slightly finer cement.

If the fineness of a cement is high there are not ordinarily any special procedures that need to be taken to maintain quality, because fineness per se does not detract from quality. If fineness were so great that it made the mix unusually sticky it would be a simple matter to redesign the mix with a lower sand content or coarser sand to get rid of stickiness.