Types of Cement With Their Definition, Properties and Uses

To make 5 to 10 percent of suitable pigments are grinded with OPC. Types of pigments are selected according to the desired color. Colored cement is also known as Colcrete. It is manufactured by adding coloring pigment to the OPC. it is used in joining tiles.

Uses of Colored Cement

• Colored cement is used for different decorative work.

It is seen that entrainment of air or formation of gas bubbles while applying cement increases resistance to frost action, fire, scaling and other similar defects. Air-entraining cement is a special type of cement which entrains tinny air bubbles in concrete.

It is produced by grinding minute air entertaining materials with clinker by adding some resinous materials e.g. vinsol resin to ordinary portland cement.

When the water in concrete gets frizzed due to low temperature, it expands. When air-entraining cement, the air voids in concrete provides space for water to expand without cracking concrete. But this type of cement does not provide high strength in concrete.

Uses of Air-Entraining Cement

• Especially it is used in areas where the temperature is very low.
• It also resists Sulphet attack.
• It is used where the de-iceing chemical is used.

In the hydration process, the expansive cement expands its volume. It can be possible to overcome shrinkage loss by using expansive cement.

This type of cement is manufactured by adding stabilizer which stabilizes the cement to expand. This can be achieved by adding 8-20% of sulphoaluminate & 15% of stabilizer to the ordinary Portland cement clinker.

Concrete made up of OPC shrinks while setting due to loss of free water. Concrete also shrinks continuously for a long time. Cement used for grouting should not shrink or change volume for this, we use expansive cement. the expansive cement doesn’t show any volume change after hardening.

There are three types of expansive cement:

1. K Type expansive cement
2. M Type expansive cement
3. S Type expansive cement

K Type expansive cement

Raw materials of these types of cement

• Portland cement
• Anhydrous tetracalcium trialuminate sulfate (C4A3S)
• Calcium sulfate (CaSO4)
•  
• Lime (CaO).

M Type Expansive Cement

Raw materials of these types of cement

1. Portland cement clinkers
2. Calcium sulfate.

S Type Expansive Cement

Raw materials of these types of cement

1. Portland cement clinkers
2. Calcium sulfate (High amount)

• Tricalcium aluminate (C3A) (High amount)

Uses of Expansive cement

• It is used in the construction of the pre-stressed concrete component.
• It is also used for sealing joints and grouting anchor bolt.
• In the construction of different hydraulic structures, this type of cement is used.

To resist the hydration process in the transportation or storage stage, clinkers are grinded with water repellent film substance such as Oleic Acid or Stearic Acid.  These chemicals form a layer on the cement particle and do not allow water to mix and start the hydration process.

When cement and aggregate are thoroughly mixed in the mixer, protective layers break and start normal hydration with some air-entrainment which increases workability.

Hydrophobic Cement is manufactured by grinding ordinary Portland cement clinker with water oleic acid or stearic acid. These acids forms as a water repellent film around the cement particle which increases the shelf life of cement.

The formed around each grain of cement reduces the rate of deterioration of the cement during long storage, transport, or under unfavourable conditions. The film is broken out when the cement and aggregate are mixed together at the mixer exposing the cement particles for normal hydration.

Uses of Hydrophobic Cement

• Usually, it is used in the construction of water structures such as dams, spillways, or other submerged structures.
• It is also used in the construction of underground structures like tunnel etc.

4. Ultra High Strength Cement

In advanced countries, at the production stage itself, an ultra-high early strength cement is generated by separating the finest fraction (above 700 m2/kg) from the rapid hardening cement.

Using special devices called the cyclone air elutriator, this is performed. Such cement is used for early concrete with very high strength.

8. High Alumina Cement

High Alumina Cement: High Alumina Cement is created by combining calcined bauxite, lime, and clinker during the production of OPC. This type of cement is made by grinding together bauxite and limestone. It is known for its high resistance to chemical attack and high heat of hydration. It is commonly used in refractory linings, furnace and kiln construction, and in high temperature applications.

For cement to be considered High Alumina Cement, the total alumina content must be at least 32%, and the weight ratio of alumina to lime must be between 0.85 and 1.30. It is commonly used in structures that are exposed to high temperatures, such as workshops, refractories, and foundries.

9. White Cement

White Cement: This type of cement is made using raw materials that have a low iron and manganese content, which results in a cement that is much whiter in color. It is commonly used in decorative concrete, architectural concrete, and terrazzo flooring. This kind of cement is produced from raw materials devoid of iron and oxide and needs to have a high proportion of lime and clay.

It is expensive and is used for architectural purposes, including precast curtain walls and facing panels, terrazzo surfaces, etc. It is also used for interior and exterior decorative work, including exterior renderings of buildings, facing slabs, flooring, ornamental concrete products, garden paths, swimming pools, etc.

What are the four general types of cement?

Purpose of having high lime content is to attain high strength in early days. It is used in concrete when formwork is to be removed early.

Since hardening of cement is due to the formation of CaCO₃ by absorbing atmospheric CO₂ by CaO, increased CaO results in increased CaCO₃ formation even at the early stage to result in rapid hardening.

QSC is produced by adding a small percentage of aluminium sulphate as an accelerator and reducing the amount of gypsum used with fine grinding. This cement is used when the work is to be completed very quickly as in static and running waters.

LHC has reduced the amount of C₃A, which is used to produce massive concrete constructions like gravity dams. LHC has compressive strength to heat of the hydration ratio of at least 7 at the age of 13 weeks.

The usual wt. ratio of CaO to SiO₂ is between 0.8 and 1.5, but Al₂O₃ wt.% is less than 10%.

This is prepared by grinding the CaO, SiO₂, and Al₂O₃ materials, melting the mixture, quenching the melt, and grinding the quenched matter to have mainly amorphous material of the above composition.

Alumina is a hydratable material and reduced alumina gives reduced hydration to produce less heat of hydration. This is important in the construction of large structures to avoid possible thermal cracking during concrete setting.

Sulphate attack on concrete is a chemical breakdown mechanism, where sulphate reacts with C3A and/or Ca(OH)₂ components of the hardened cement forming ettringite, which is hexacalcium aluminate trisulphate hydrate [(CaO)₆(Al₂O₃) (SO₃) 32H₂O = C₆ASH₃₂].

Sulphate ions can react with C₃A and/or Ca(OH)₂ in hardened concrete in the presence of water forming gypsum.

These newly formed ettringite and gypsum crystals occupy empty spaces of concrete, and as they grow, they tend to damage the paste by cracking. The most important parameters determining the sulphate attack are C₃A, C₃S/C₂A ratio, and C₄AF.

It has been reported that the addition of pozzolonic admixtures such as fly ash reduces the C₃A content of cement when sulphate is present in water and soil used; in places like canal linings, culverts, retaining walls, and siphons, it is important to use SRC. SRC is prepared by maintaining C₃A content below 6%.

BFSC is prepared by grinding the clinkers with ∼60% slag. BFSC resembles properties of the Portland cement and is used for works in which economic considerations are predominant. HAC is obtained by melting a mixture of bauxite and lime and grinding the mixture with the clinker.

Since it contains high alumina content, it is rapid-hardening cement with initial and final setting times of about 3.5 h and 5 h, respectively. HAC is used in works where concrete is subjected to high temperatures, frost, and acidic conditions. WC is prepared from raw materials free from iron oxides and oxides of other transition metals such as Cr, Mn, Cu, V, and Ti.

The colouring effect takes the order Cr₂O₃ > Mn₂O₃ > Fe₂O₃ > V₂O₃ > CuO > Ti₂O₃. As such, the amounts of these transition metal ions, particularly Cr³⁺, Mn³⁺, and Fe³⁺, should be minimized to form white cement. Usually, Cr₂O₃, Mn₂O₃, and Fe₂O₃ are kept below 0.003%, 0.03%, and 0.35%, respectively, in the clinker. Cheap quarried raw materials usually contain Cr, Mn, and Fe.

For example, lime stones and clays usually contain 0.3–1% and 5–15% Fe₂O₃. Keeping Fe₂O₃ below 0.5% is desirable to make WC, and as such, kaolin and sand are used instead of other clays in making WC.

The abrasiveness of sand particles with size <45 µm also ensures less wearing of chrome-steel grinding mill used to grind raw materials, which would otherwise contaminate the mixture with Fe and Cr. Usually, sand is ground separately using ceramic grinding media to avoid chromium contamination.

WC is costly and hence used in aesthetic applications such as precast curtain wall and facing panels and terrazzo surface.

Contrary to WC, CC is prepared by deliberately adding mineral pigments to cement. CCs are widely used in decorative works on floors. Iron oxides are used to get red, yellow, and black base colours, and several mixed colours such as browns-terracotta-tuscany-sepia-beach.

Standard green and blue pigments are chrome oxide and cobalt aluminium oxide, respectively. TiO₂ is the usual white pigment. PzC is prepared by grinding the pozzolanic clinker with the Portland cement. It is used in marine structures, sewage works, and for laying concrete under water such as in bridges, piers, and dams.

AEC is produced by adding air-entraining agents that are surfactants such as alkali salts of wood resins, synthetic detergents of the alkyl-aryl sulphonate type, calcium lignosulphate derived from the sulphite process in paper making, and calcium salts of glues and other proteins obtained in the treatment of animal hides, animal and vegetable fats, oil and their acids, wetting agents, aluminium powder, and hydrogen peroxide, during the grinding of the clinker.

They are added in 0.025–0.1% in either solid or liquid form. At the time of mixing, AEC produces tough, tiny, discrete noncoalescing air bubbles of 10–500 µm in diameter in the body of the concrete. These bubbles can compress to some extent, and hence, they can absorb stress created by freezing.

HpC is prepared by adding water-repellent chemicals [26]. They are prepared particularly for use in high-rainfall regions to prevent water absorption during storage.

Particles of HpC are coated with nonpolar substances, usually by adsorbing oleic acid, stearic acid, and so on, to cement particles.

When adsorbed, these surfactant molecules self-assemble by coordinating with surface cations through their carboxylic acid groups thereby allowing the nonpolar hydrocarbon chain to extend from the particles.

When a water drop falls on them, they are stuck on hydrocarbon chains and stay as spherical particles as does by the lotus leaf. The cement particles are then not wetted, and water drops roll off when slightly slanted.

These hydrophobic coatings prevent the attacks by chloride and sulphate ions, and hence, they resist to deterioration of concretes by these ions.