Civil Engineering - Concrete Technology - Discussion

Cement mixtures.

Mixtures are always listed as parts Cement to Sand to Aggregate. Following are typical cement mixtures description:

Rich: 1 part cement, 2 parts sand, 3 parts coarse aggregate. A rich mix is used for concrete roads and waterproof structures.

Standard: 1 part cement, 2 parts sand, 4 parts coarse aggregate. A standard mix is used for reinforced work floors, roofs, columns, arches, tanks, sewers, conduits, etc.

Medium: 1 part cement, 2 1/2 parts sand, 5 parts coarse aggregate. A medium mix is used for foundations, walls, abutments, piers, etc.

Lean: 1 part cement, 3 parts sand, 6 parts coarse aggregate. A lean mix is used for all mass concrete work, large foundations, backing for stone masonry, etc.

All the options are correct. Please check and rectify the correct answer.

Yes, the rich mix is stronger than a lean mix.

How can option A be incorrect?

Anyone describe it.

I think the correct one is either opp C or E.

It is Option C.

I think the reason behind A as the answer is the word Excessive water. Because more the water less is strength.

Lean mixes bleed more as compared to rich ones. So answer A is incorrect.

Please read the question carefully option E is right because they ask incorrect statement and all option are correct actually, so the answer is option E i.e none of this.

A rich mixture contains a high proportion of cement. A lean mixture is a mixture of concrete or mortar with a relatively low cement content. A harsh mixture of concrete is one without mortar or aggregate fines, resulting in an undesirable consistency and workability.

Option E is correct. I also agree.