civ2043 pr1

Question 1

What is hydraulic cement?

Answer 1

1.Fine mineral powder
2. React with water by process called hydration to form compounds that are volumentrically stable, durable and increase in strength with age.

Question 2

Basic constituents

Answer 2

Oxides of Ca ,Si , Al and Fe

most widely known cement is portland cement

Question 3

portland cement raw materials

Answer 3

1. Limestone
   2.Shale
   3.Clay

Question 4

What is produced when hitting Clay and shale

Answer 4

Clinker

Question 5

Chemical compounds that are in clinker

Answer 5

C2S - Dicalcium Silicate
C3S - Tricalcium Silicate
C3A - Tricalcium aluminate
C4 AF - Tritracalcium alumineferrite

Question 6

What CSH(Calcium Silicate Hydrate) do ?

Answer 6

Provides strength to cement paste

Question 7

What Calcium Hydroxide do?

Answer 7

-increases pore solution ph(12.5)
-Accerates reaction with SCM’s
-Protects steel reinforcement from corrosion

Question 8

what are products of hydration and what do they do?

Answer 8

• CSH
• Calcium hydroxide

Question 9

Explain the relationship between the W/C ratio and strength or porosity(pores)

Answer 9

A lower W/C ratio increases strength and reduces porosity, while a higher W/C ratio decreases strength and increases porosity due to excess water forming voids

Question 10

what is SCM’s ?

Answer 10

SCMs (Supplementary Cementitious Materials) are materials like fly ash, GGBS, and silica fume that partially replace cement to improve concrete strength, durability, and sustainability.

Question 11

Why SCM’s used ?

Answer 11

• Reduce cost
  -Reduce carbon emission and industrial waste
• improves concrete microstructure and durability

Question 12

drawbacks(disadvantage) of SCM’s

Answer 12

• slow rate strength development
  -potential durability issues (corrosion of reinforced concrete due to carbonation)