Why does a concrete pump truck need lubricating agent? Can concrete lubricating agent be applied into concrete?

contents of this articlewhy does a concrete pump truck need lubricant? what is concrete moisturizer? can concrete moisturizer be applied inside concrete? does c20 fine stone need to be passed through the pump truck first? what does pipe moistening mortar mean? is the lubricant easy to produce? what kind of chemical raw material is the…