Higher w/c has lower heat of hydration

Lower w/c leads to more capillary pores in the concrete

Lower w/c has lower heat of hydration

Higher w/c leads to higher slump

Lower w/c leads to less capillary pores in the concrete

None of these

20 m

30 m

3 m

2 m

time of transit

size of aggregate

water-cement ratio

the air in the mix

28 days

Until it hardens

7 days

1 day

It is a form of segregation

It should be always eliminated

None of the above

Aggregates settle downwards under gravity

It can be useful to finishing operations

shrinks

mixes

none of the above

expands

Aggregates settle due to gravity, displacing free water which rises to the highest surface of the concrete

Aggregates settle due to gravity, displacing free water and cement paste which accumulates at the highest surface of the concrete

Aggregates settle due to gravity, displacing free water and cement paste which accumulates at the lowest surface of the concrete

Aggregates settle due to gravity, displacing free water which accumulates at the lowest surface of the concrete

All of the above

Use cement with low tri-calcium aluminate content

Use coarser cements

Use cement with high calcium chloride

screed vibrator

none of the above

form vibrator

internal vibrator

Aggregate grading has no impact on concrete workability.

Workability loss only occurs when concretes are improperly mixed.

A higher free water content in concrete mixes results in loss of workability.

A higher free water content in concrete mixes leads to increased workability.