What is m15 grade of concrete?:-in m15 grade of concrete M stand for mix and numerical figure 15 is stand for comprehensive strength of concrete which is gain in 28 days of curing time. m15 concrete ratio in 1 m3:- m15 concrete ratio in 1 cubic metre is mixture of cement, sand and aggregate by adding water. cement sand & aggregate ratio in m15 grade 1m3 …