Characteristics and Types of Portland cement

American Society for Testing and Materials (ASTM) designation C150 has specified the 8 types of Portland cement. Many kinds of Portland cement are produced to meet the needs for various purposes

Type	Name
1	Normal
1a	Normal, air entraining
2	Moderate sulfate resistance
2a	Moderate sulfate resistance, air entraining
3	High early strength
3a	High early strength, air entraining
4	Low heat of hydration
5	High sulfate resistance

Type 1) Normal Cement:

It is multi-purpose general cement which is used in solid concrete for constructing pavements and floors, reinforced concrete pipes, buildings, tanks, and bridges.

It is basically used in concrete which is not exposed to excessive exposure, such as sulfate assault from water and soil, to an exceptional temperature rise.

Type 2) Moderate sulfate resistance cement:

It is used where safety measures aligned with reasonable sulfate assail is vital as in drainage arrangement, which may be affected by restrained sulfate absorption from ground waters

Because of less heat production, hot weather is preferable.

It typically produces low warmth of hydration at the sluggish rate than Type I cement and consequently can be used in mass construction like huge piers, weighty abutments, and holding walls

Type 3)  High early strength cement:

• It is synthetically and physically like Type I bond, aside from that its particles have been ground better
• It gives high early qualities at an early period, as a rule, a week or less
• It is utilized when structures should be expelled at the earliest opportunity or when the structure must be put into administration rapidly
• It is favored in frosty climate for the diminishment in the curing time frame

Type 4)  Low heat of hydration cement:

• It is utilized where the rate and measure of warmth produced from hydration must be minimized
• It creates quality at a slower rate than other concrete sorts
• It is most appropriately utilized as a part of monstrous solid structures, for example, vast gravity dams, where the temperature rise coming about because of warmth produced amid solidifying must be minimized to control the solid splitting

Type 5)  High sulfate resistance cement:

• It is utilized just as a part of cement presented to extreme sulfate activity – essentially where soils or ground waters have high sulfate content
• Its high sulfate resistance is because of its low C3A substance of around 4%
• It is not impervious to acids and other profoundly destructive substances
• Air-Entraining Portland Cements

TYPES 1a) , 2a) , and 3a):

• These concretes have same creation as Types I, II, and III, separately, aside from that little amounts of air-entraining material are between ground with the clinker amid produce

• These bonds deliver concrete with enhanced imperviousness to stop defrost activity and to scaling brought about by chemicals connected to snow and ice expulsion

WHITE PORTLAND CEMENT:

• It has creation same as Type I or Types III concrete, aside from that it has a white shading rather than dim shading

• It is made of chose crude materials containing insignificant measures of iron and magnesium oxides-the substances that give bond its dim hues

• It is utilized basically for building purposes

BLENDED HYDRAULIC CEMENT:

• These types of cement are manufactured by thoroughly and consistently merging of the Portland cement and the by-product substances, like blast-furnace slag, fly ash, silica fume.

ASTM C 596 classifies five levels of mixed cement:

• Portland blast-furnace slag cement-Type IS
• Portland pozzolana cement-

Type IP and Type P:

•  Pozzolana-modified Portland cement-Type I(PM)
• Slag cement-Type S
• Slag-modified Portland cement- 

Type I(SM):

• These types of cement are used in mortar for masonry building constructions
• ASTM C 91 classifies masonry cement as Type N, Type S, and Type M

Expansive Cement:

• These types of cement are chiefly used in concrete for reduction organization
• ASTM C 845 categorizes masonry cement as Type E-1(K), Type E-1(M), Type E-1(S)

Special Cement (Not covered by ASTM):

Type	Uses
1. Oil-well cement	For sealing oil wells
2.Waterproof Portland cements	For reducing capillary water transmission
3. Plastic cement	For making plaster and stucco

Chemical Compounds in Portland Cement:

As shown before the burning operation of the unrefined materials leads to the reaction among the oxides and four mix compositions are created in the final cement product, as follows:

• C3S = 3CaO.SiO2 (Tricalcium silicate)
• C2S = 2CaO.SiO2 (Dicalcium silicate)
• C3A = 3CaO.Al2O3 (Tricalcium aluminate)
• C4AF = 4CaO. Al2O3.Fe2O3 (Tetracalcium aluminaferrite)

Functions of Compound Composition

⧪ C3S

• Hydrates and solidifies quickly and is to a great extent in charge of beginning set and early quality
• Early quality of the bond is higher with expanded rates of C3S

⧪ C2S

• Hydrates and solidifies gradually
• Contributes to a great extent to quality increment at ages past one week

⧪ C3A

• Liberates a lot of warmth amid the initial few days of hydration and solidifying
• Contributes somewhat too early quality improvement
• Gypsum added to the concrete backs off the hydration rate of C3A
• Cement with low rates of C3A are particularly impervious to soils and waters containing sulfates

⧪ C4AF

• Does not assume any noteworthy part of the hydration