Air entrainment was found by chance in the mid-1930s.[2] At that time, cement manufacturers ended up employing a grinding aid to enhance the entire process of grinding cement. This grinding support was a combination of various chemicals, which include salts of wood resin, which have been included on the cement https://edgarhkige.wikicommunication.com/5408826/the_smart_trick_of_pce_plasticizer_that_no_one_is_discussing