Unit 6

Question 1

The ratio of the amount of water, minus the amount of water absorbed by the aggregates, to the amount of cementitious materials by weight.

Answer 1

Water-cementetious ration or w/cm ratio

Question 2

Hardening occurs because of the chemical reaction called ________.

Answer 2

Hydration

Question 3

The ease of mixing, placing , consolidating and finishing concrete is called ___________.

Answer 3

Workability

Question 4

The water content of the mixture is the single most important factor that affects workability [ True or False].

Answer 4

True

Question 5

In adding water on site, all water additions shall be completed within 20 minutes from the start of the first water addition. [True or False]

Answer 5

False, within 15 minutes

Question 6

A material other than water, aggregates, and hydraulic cement that is used as an ingredient of concrete and is added to the batch in controlled amounts immediately before or during mixing to produce some desired modification to the properties of the concrete.

Answer 6

Admixtures