Concrete

Question 1

concrete is a combination of . . .

Answer 1

Mortar+coarse aggregate

Question 2

Mortar is . . .

Answer 2

Paste + fine aggregate

Question 3

Paste is . . .

Answer 3

Cement+admixtures+water

Question 4

What are some advantages of concrete?

Answer 4

Cast into shape
Affordable
High compressive strength
Versatile mixtures
50-120 yr
Fire resistance
Water resistance
Low-conductivity
Easy to process
High thermal mass
Readily available materials

Question 5

What are some disadvantages of concrete?

Answer 5

High carbon footprint
Low tensile strength
Specific sand required for manufacture
Takes time to strengthen
Cement+water is exothermic

Question 6

What makes concrete and steel such a good marriage?

Answer 6

Steel corrodes, concrete does not
Steel is strong in tension, concrete is not
Concrete can bind to steel very well

Question 7

Concrete is susceptible to

Answer 7

Creep
Deterioration-freeze thaw weathering,chemical corrosion
Porous damage

Question 8

Concrete is inevitably porous because

Answer 8

Hydration products made from the reaction of cement and water may form a matrix with voids

Question 9

Lecture 5 summary

Answer 9

Humans use an awful lot of concrete
Not many structures don’t contain concrete
Usage will continue to increase
Durable, sustainable???
Expensive problem->increase->aging infrastructure
Not many options to replace concrete (at large scale)