Question

A mixture of cement, gravel, coarse sand and water is called:
A. mortar
B. concrete
C. slurry
D. hardener

Answer 1

Hint: All the options given are building materials used in some way or the other. The answer can be found by knowing the compositions of these materials. Gravel is aggregation of rock fragments, coarse sand has higher grit than fine washed sand and cement is a binder material.

Complete step by step answer:
Let us discuss the options and understand their composition, to get a clear figure:

A. Mortar: ‘Mortar’ word is derived from a Latin word which means crushed. Mortar includes pitch and soft mud or clay like used between mud bricks. It is a paste which binds blocks of the building such as bricks and stones to fill the irregular gaps between the units and to add decorative patterns to masonry walls. Bricklayers make mortars using a mixture of sand, a binder and water.

B. Concrete: Concrete is a composite material which is composed of coarse and fine aggregate bounded together with cement paste and mixed with water that hardens with time. Also used sometimes with other hydraulic cements like with Portland cement to form Portland cement concrete.

C. Slurry: Slurry is a mixture of solids denser than water suspended in aqueous solvents. The size of solid particles varies from 1 micron to hundreds of millimeters. It is composed of glass beads in silicone oil which are flowing down an inclined plane.

D. Hardener: It is the one that hardens a substance. A hardener is a component of certain types of mixtures and as composition is different, the property becomes different. A hardener is used to increase the resilience of the mixture once it sets.
The correct answer is option ‘b’. A mixture of cement, gravel, coarse sand and water is concrete.

Additional Information:

Type of mixture	Applications of the mixtures
Mortar	Can be used as a glue-like structure for projects that require stone or ceramic installation.
Concrete	Used to provide tensile strength. It is one of the most frequently used building materials.
Slurry	Slurry is used as a means of transporting solids, the liquid being a carrier that is pumped on a device such as a centrifugal pump.
Hardner	Hardener is used as a curing component. A hardener can be a reactant and a catalyst in the chemical reaction that occurs during the mixing process.

So, the correct answer is “Option B”.

Note: Concrete is different from mortar where concrete is itself a building material but mortar is a bonding agent that typically holds tiles, bricks and other masonry units together.
Concrete and cement are distinct terms; cement makes up from 10% to 15% of the total mass of concrete. Concrete includes cement and other things, like aggregates (sand, water) and paste.