class meeting
8.These gentlemen from the upper-class society are going to have a meeting here.
9.Results of experiments indicate that concrete mixed by this ratio will posses the strength of C50, good workability, the shrinkage of it at 28days is lower than half that of the pure cement, with a permeability class P30, alkali content 2.4 kg/m3 , meeting the requirements for using in humidity conditions and durability.

