Question

In what ratio are the mixture of cement, gravel and sand mixed to form concrete?
(A) 1:2:4
(B) 1:3:6
(C) both A and B
(D) 1:1:1

Answer 1

Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. The composition and strength of cement is a very essential part to pay a lot of attention too.

Complete step by step answer:
Cement generally refers to a very fine powdery substance chiefly made up of limestone (calcium), sand or clay (silicon), bauxite (aluminum) and iron ore, and may include shells, chalk, marl, shale, clay, blast furnace slag, slate. A cement is a binder, a substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together.
Gravel are small fragments of rock, used for laying on the beds of roads and railways, and as ballast. Gravel, along with sand, is used for the manufacture of concrete, as well as for mixing with asphalt as part of road construction. It can be used as the base layer for roads before being covered with tarmac, and is also commonly used to surface roadways, especially those in rural areas and in icy conditions.
Sand is a granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.
For nominal mix design, the standard ratio between cement, gravel and sand, which is as follows:

Grade	Cement	Gravel	Sand
M5	1	5	10
M10	1	3	6
M15	1	2	4

So, the correct answer is “Option C”.

Note: The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or $Si{{O}_{2}}$ ), usually in the form of quartz. The second most common type of sand is calcium carbonate.