In the course of practice, we encountered some concrete enterprises produce C35 concrete 28d strength of 45MPa or even more, which is unreasonable and a waste of resources.
The principle of appropriate strength, the requirements of concrete strength should not be too high, the concrete strength of 115% of the surplus coefficient can be, that is, C35 concrete in the age of the basic can reach 38 ~ 40MPa is more appropriate.



Many scholars believe that reducing the slump of concrete as much as possible, re-promoting the use of dry-hard, semi-dry-hard or plastic concrete in preference to the use of large-flow concrete as little as possible, is still an important principle for good workability in the present situation.
In the test, it was found that using the same kind of material, water consumption and cementitious materials remain unchanged, change one or two of the parameters, such as additives, sand fineness modulus, sand rate, etc., it is possible to adjust the slump of concrete from 160mm to 220mm.