Air entrainment was found out by accident while in the mid-1930s.[two] At that time, cement manufacturers were utilizing a grinding assist to enhance the entire process of grinding cement. This grinding assist was a mixture of varied chemicals, including salts of wood resin, which were being added on the cement https://zanderfhgfd.wikiparticularization.com/1527778/the_ultimate_guide_to_stamped_concrete_paint