what is m20 m25 and m30 mix, if any body can please describe or in lay-mans terms aggregates and ratios for these concrete mixes if possible water and consistency to be used?
M20 is designed what should be the strength of concrete after 3 days and 28 days. Similarly M25 and M30.
The composition of the concrete mix comprises cement, fine aggregates (River sand) than course aggregates graded as per code of size 20mm, 12.5mm, 10mm and admixture and water in proportional depending upon the designation of strength of concrete.