Question

what is the influence of the fineness modulus on the properties of concrete mixes?

Answer 1

Fineness modulus is an empirical figure which is calculayed by dividing total percentage of aggregate retained on a sieve by 100.

It is a figure that can go in fractions.

Following are the effects on the concrete mix :

Higher the value of FM, coarser iels the aggregate and hence packing of concrete would not be sufficient.

If we talk in context of sand then, fineness modulus of sand affects the compressive strength of concrete in a btter way. Higher FM increases the cmpressive strength of the concrete.

Fineness modulus has little impact on permeability of the concrete.

Net cost of concrete decreases by increase in FM value of aggregate.

It doesn't mean that we can use a very high FM aggregate for cost savings because it will ultimately affect workability of the concrete too.

Hence, FM of 2.7 must not exceed.