Portland Cement (Lecture 4) Flashcards
Type I Portland Cement
For General Use. No limits are placed on any four principal compounds
Type II Portland Cement
Moderate Sulfate resistance and moderate heat of hydration. Spec limits the C3A content to a max 8%
Type III Portland Cement
High Early Strength. C3A content is limited to max of 15%
Type IV Portland Cement
Low heat of hydration. max limits of 35% on C3S and 7% on C3A. Minimum 40% C2A.
Type V Portland Cement
High sulfate resistance. Max limit 5% on C3A.
Air entraining Portland Cement
Type IA, IIA, IIIA.
Pozzolan
siliceous or siliceous and aluminous material that has no cementing property but reacts with water to create Calcium hydroxide to form cementious product.
Properties of Pozzolan
1) Slow reaction
2) consumes CaOH
3) Fills large capillary spaces making concrete less permeable and more durable.
Blast Furnace Slag
Nonmetallic waste product from manufacturing of iron and steel
Granulated Slag
Glassy Product formed by rapid cooling of molten blast furnace slag.
Is self cementing
Portland Blast Furnace Slag Cement
Type IS. blend of portland cement with 25-70% by weight of granulated blast furnace slag.
Portland Pozzolan Cement
Type IP & P. blend of portland cement with 15-40% fine pozzolan by weight.
Type P has lower early strength, used when high strength early is not required.
Effect of Pozzolan and Blast Furnace Slag on durability of concrete
- Water resistance increased
- Permeability is reduced
- Sulfate resistance increased
- Alkali aggregate expansion is reduced
Colored cement
formed by adding pigments to white cement or using clinkers. similar to normal portland cememnt
White cement
used to produce architectural concrete where white is desired. Formed by reducing iron content.
Hydraulic cement
hardens by reacting with water to form water resistant product. Portland cement is hydraulic.
Non hydraulic cement
reacts with water to form product which is not stable in water. Hydration product may act with air to form water resistant product. EX. Quicklime
Who invented portland cement?
Joseph Aspdin
Why was portland cement named so?
Named after the concrete it produced resembling the color of the natural limestone quarried on the isle of portland.
What is the largest size of portland cement?
Finer than 200 sieve (75micrometers)
What is the typical specific gravity of portland cement
3.15
What is the typical unit weight of portland cement
94pcf
How much does a bag of portland cement weigh
94lbs
What are the four main oxides in portland cement
Calcium Oxide
Silicon Oxide
Aluminum Oxide
Iron Oxide
What are the four main compounds that form portland cememnt
Tricalcium Silicate- C3S
Dicalcium Silicate- C2S
Tricalcium Aluminate- C3A
Tetracalcium Aluminoferrite- C4AF
What chemical abbreviation is C
calcium oxide
What chemical abbreviation is S
Silicon Oxide
What chemical abbreviation is A
Aluminum Oxide
What chemical abbreviation is F
Iron oxide
What are the properties of C3S
Hydrates and hardens rapidly
responsible for initial set and early strength
What are the properties of C2S
Hydrates and hardens slowly
Contributes to strength increase beyond 1 week
What are the properties of C3A
Hydrates rapidly and gives off a lot of heat
Contributes slightly to early strength
More susceptible to sulfate attacks which cause expansion and cracking
What are the properties of C3AF
Contributes little to strength. Reduces clinkering temp in production of cement which reduces cost
Is cement hydration endothermic or exothermic?
Exothermic (heat is generated)
What does C3S and C2S produce?
Calcium Silicate Hydrate- strong and stable in water
Calcium Hydroxide- soluble in water
