Deck 6: Concrete

Question 1

Water is used in concrete mixes to

A) Increase the strength of the concrete
B) Reduce the strength of the concrete
C) Enable the cement to set
D) Enable the aggregates to bond with the cement
E) Reduce the heat generated during the setting process

Answer 1

C

Question 2

Fine aggregates are used in concrete mixes to

A) Enable the concrete to be poured easily
B) Fill the voids between the coarse aggregate particles
C) Provide increased strength to the concrete
D) Soak up the excess water in the concrete
E) Provide colour to the concrete

Answer 2

B

Question 3

Rapid Hardening Portland Cement differs from Ordinary Portland Cement in that it

A) Is more finely ground
B) Contains more limestone
C) Contains more iron oxide
D) Contains more silica
E) Is made at higher temperatures

Answer 3

A

Question 4

Fine aggregates are distinguished from coarse aggregates in that they

A) Have a strength of less than 5 N/mm²
B) Have a strength greater than 5 N/mm²
C) Have particle sizes of less than 5mm
D) Have particle sizes of greater than 5mm
E) Are synthetic

Question 5

Sintered pulverised fuel ash lightweight aggregate is made by

A) Fusing furnace clinker into lumps and then crushing it
B) Spraying molten slag with water
C) Heating shale to cause it to exfoliate
D) Firing moistened burnt coal residue to form pellets
E) Crushing volcanic lava

Question 6

Concrete can be made more durable by

A) Increasing the amount of cement used in the mix
B) Increasing the amount of water used in the mix
C) Increasing the amount of fine aggregate used in the mix
D) Reducing the amount of coarse aggregate used in the mix
E) Reducing the number of air voids in the mix

Question 7

An excessive amount of water in a mix can

A) Weaken the concrete
B) Reduce the drying shrinkage in the concrete
C) Reduce the drying time
D) Reduce the setting time
E) Increase the fire resistance of the concrete

Question 8

A 1:3:6 concrete mix contains

A) 1 part cement to 3 parts coarse aggregate to 6 parts fine aggregate
B) 1 part cement to 3 parts fine aggregate to 6 parts coarse aggregate
C) 1 part fine aggregate to 3 parts cement to 6 parts coarse aggregate
D) 1 part coarse aggregate to 3 parts cement to 6 parts fine aggregate
E) 1 part fine aggregate to 3 parts coarse aggregate to 6 parts cement

Question 9

Proportions of materials in a mix are more correctly specified by weight than volume because

A) Water weighs more than cement
B) Coarse aggregates weigh more than fine aggregates
C) Segregation affects the volume of coarse aggregates
D) Bulking affects the volume of fine aggregates
E) Dense aggregates have a greater volume than lightweight aggregates

Question 10

For every 1 kg of cement used in a mix having a water:cement ratio of 0.52

A) 0.26 litres of water should be added
B) 0.39kg of water should be added
C) 0.52 litres of water should be added
D) 0.65m³ of water should be added
E) 0.78kg of water should be added