Concrete and Cement

Question 1

What are the three main components of concrete

Answer 1

Cement, water and aggregate

Question 2

What is the difference between mortar and concrete

Answer 2

Mortar has more fine aggregate such as sand

Question 3

What is hydraulic cement

Answer 3

Cement that has inorganic, non metallic compounds that when react with water set

Question 4

What is Portland cement

Answer 4

Portland cement is a strong cement used in construction that contains
a) calcium oxide and
b) silicon dioxide

Question 5

What does w/c mean

Answer 5

Water to cement ratio

Question 6

What are admixtures and some examples

Answer 6

Admixtures are extra additives used to give certain properties such as:
water reducing,
retarding
accelerating

Question 7

What is curing

Answer 7

Curing is the maintenance of optimal conditions for hydration of cement

Question 8

What is the process of making cement

Answer 8

1) Limestone sourced and ground into powder
2) Sand and clay are added and grinded down again
3) Heated up in a kiln to make ‘clinker’
4) ‘clinker’ is mixed with gypsum and then ground again into fine cement.

Question 9

What is grading

Answer 9

Grading is the process of using multiple sizes of aggregate so there are no gaps in the material

Question 10

What are some factors that effect concrete strength

Answer 10

Age
Water/cement ratio
Duration of curing
Curing temperature
Compaction
Shrinkage

Question 11

What is shrinkage and when is it a good thing

Answer 11

Shrinkage is when the concrete shrinks due to loss of moisture from the cement.
It is useful in reinforced concrete as the concrete grips to the steel rebar more