Q 01/05

Concrete is the second-most-used substance in the world after what?

A) Steel

B) Water

C) Wood

D) Oil

Answer · why

B) Water

Water: concrete is the most widely used substance after water, and making its cement accounts for up to 8% of global CO2 emissions.

Q 02/05

What are the two basic components of concrete?

A) Lime slaked with wood ash

B) Sand mixed with fired clay

C) Steel mesh set in stone

D) Aggregate bound by a cement

Answer · why

D) Aggregate bound by a cement

Aggregate bound by a cement: the aggregate must be clean, because dirt or clay clinging to it can weaken the finished concrete.

Q 03/05

What is the chemical process by which cement sets and hardens into a solid?

A) Hydration

B) Fermentation

C) Sublimation

D) Oxidation

Answer · why

A) Hydration

Hydration: in cold weather an accelerator is added to speed it up, and the heat the faster reaction gives off helps offset the cold.

Q 04/05

How does mortar, used to bond bricks, differ from concrete?

A) It contains no sand at all

B) It is far stronger when set

C) It contains only fine aggregates

D) It is mixed without any water

Answer · why

C) It contains only fine aggregates

It contains only fine aggregates: mortar is sand, binder and water with no gravel, which gives it a smooth texture a trowel can spread between bricks.

Q 05/05

The word 'concrete' comes from a Latin word meaning what?

A) Mixed with lime

B) Compact or condensed

C) Poured together

D) Quarried stone

Answer · why

B) Compact or condensed

Compact or condensed: Latin concretus comes from concrescere, 'to grow together', and English took it for things formed of separate parts fused into o...