chap 1

Question 1

concrete is a mixture of x and x

Answer 1

aggregates, paste

Question 2

the term paste refers to the mixture of x and x

Answer 2

portland cement, water

Question 3

aggregates make up x to x % of the weight of a concrete mix

Answer 3

70, 80

Question 4

the chemical reaction known as x causes concrete to harden

Answer 4

hydration

Question 5

hydration is a chemical reaction between x and x

Answer 5

cement, water

Question 6

conventional concrete has a compressive strength in the range of x to x mpa, ( x psi)

Answer 6

20 to 40 mpa, 2900 to 5800 psi

Question 7

the compressive strength of concrete is usually measured at a concrete age of x

Answer 7

28 days

Question 8

normalweight concrete weights aprox x kg/m^3 (lb/ft^3)

Answer 8

2350 kg/m^3, 148 lb/ft^3

Question 9

heavyweight concrete may weigh up to x kg/m^3 (lb/ft^3)

Answer 9

3200 kg/m^3, 200 lb/ft^3

Question 10

x shrinkage appears in the surface of fresh concrete soon after placement when water evaporation is excessive

Answer 10

plastic