I have generally mixed mortar for CMU as follows: One measure type “M” portland, 1/4 measure hydrated lime, 2 1/4 to 3 times the total of portland and lime of sand. That’s what my manual from trade school says and what I’ve done for nearly 30 years (I still refer to my trade school manuals occasionally).
I have the Taunton “Foundations and Concrete Work” book. In the section about block foundations there is no mention of lime in the mortar mix. I was taught that the lime makes the mix more workable and easier to stick to the buttered ends of the block. Has something changed?
“But I say to you who hear, love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you…. and just as you want people to treat you, treat them in the same way.”
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No, sir. Nothing has changed except the trend to use pre-blended, just-add-water mortar mixes. Labor costs too much to deal with the sand pile and separate bags of cement and lime and engineers don't trust hodcarriers to product consistent batches of mortar that will yield the strength they require.