What are the different market forms of steel?

Angle section

Angle section has two legs. If two legs are equal in length then they are called equal angle section otherwise they are called unequal angle section. They are available in sizes varying from 20mm X 20mm X 3mm to 200mm X 200mm X 25mm and their weight are 9 N/m and 736 N/m unequal angle section are available in sizes varying from 30mm X 25mm X 3mm to 200mm X 150mm X 18mm. Used for the construction of steel roof truss, steel columns, steel beams etc

Channel section

Channel section have a web two equal flange A Channel section is designated by the height of the web and the width of the flange. Available in sizes from 100mm X 45mm to 400mm X 100mm with weight 58N/m and 494 N/m respectively. Used for the construction of steel built in columns, beams, steel bridges etc

T section

T section Consists of web and flange. It is designated by the overall depth and width. Available in sizes from 20mm X 20mm X 8mm to 150mm X 150mm X 10mm and their weight are 9N/m and 228 N/m respectively. T section Used for the construction of steel built up sections, chimneys, steel bridges etc

I section

I section are commonly known as rolled steel joists (RSJ) . I section Consists of a web and two flange. It is designated by the overall depth of flange and weight per meter length. . Available in sizes from 75mm X 50mm to 600mm X 210mm with weight 61N/m and 995N/m respectively Used for the construction of columns, beams, grillage foundations etc. Unequal I section are used as rails.

Flat bars

Available in width varying from 3 to 40 mm Used for the construction of steel grill work , window, gates etc.

Square bars

These are bars with square sections. Available in sizes varying from 5mm square to 25mm square. and weight per meter length are 2N and 49 N . Used for the construction of steel grill work , window, gates etc.

Round bars

These are bars with circular sections Available in diameter varying from 5mm to 25mm. . and weight per meter length are 1.5N and 38 N . Used for the construction of steel grill work , window, gates etc. and as reinforcement in RCC works.

Expanded metal

Formed by cutting and expanding plain sheets. A diamond mesh appearance is formed through out the area. These are available in length 1 to 3m and width 5m. Used for as reinforcement in foundation, road work etc.

Plates

Available in different sizes and thickness varying from 5mm to 50mm, and weight are 392 N/mm2 to 3925 N/mm2. Used to connect steel beams for extension of the length. Also Used for the construction of steel built up sections

Corrugated sheets

These are formed by passing steel sheets through the grooves. These grooves bend and press the sheets and the corrugations are formed. These Corrugated sheets are galvanized and they are called GI sheets. . Used for roof covering Material.

Mild steel

Mild steel are corrosion resistant so they can increase the life of the structure. Used for the construction of light and the heavy steel structures. Like ship, railway, building etc

Tor steel

The most commonly used reinforcement in RCC is Tor steel the other names are deformed steel bar, HYST bar and CWD bar. Used for the construction of reinforcement in RCC works road, bridges, dams etc

HYST steel

High Yeild Strength Deformed steel.having strength of 415 MPa These have projections on their surface and are produced by the cold twisting of deformed bars. Due to the presence of the ribs on the surfaces the following properties are improved yield strength, bond strength, tensile strength.

Explain different types of cement

Explain different types of cement

Ordinary Portland cement

These are available in many grades , namely 33 grade , 43 grade, 53 grade etc If 28 day strength is not less than 33N/mm2 then it is called 33 grade cement. If 28 day strength is not less than 43N/mm2 then it is called 43 grade cement. Use of higher grade cement offers many advantageous for making stronger concrete. Although they are little costlier than the low grade cement, they offer 10 to 20% saving in the cement consumption and also they offer many other hidden benefits. One of the most important benefits is the faster rate of development of the strength. Used for the ordinary works.

Rapid hardening cement

As the name indicate it develops the strength rapidly. This cement develops at the age of three days , the same strength as that expected of Ordinary Portland cement at seven days. The rapid rate of development of the strength is due to the higher finess and higher C3S and lower C2S. Used for the Road repair work, Early removal of the formwork, Cold weather concrete.

Sulphate resisting cement

Ordinary Portland cement is sucessible to the sulphate attack. Sulphate react with the free calcium hydroxide to form calcium sulphate and the hydrate of calcium aluminate to form calciumsulphoaluminates., the volume of which is approximately 227% of the volume of the original aluminates. Their expansion results in cracks. To remedy this the use of the cement with the low C3A is recommended. Such cement with the low C3A and content is known as the Sulphate resisting cement. Used for Marine condition, Foundation in soil infested with sulphates, Concrete used for the fabrication of pipes etc

Quick setting cement

As the name indicates this type cement set quickly. This property is brought out by reducing the gypsum content at the time of the clinker grinding. This cement is required to mix, place and compacted very easly. Used for the underwater construction.

Super sulphated cement

Super sulphated cement is manufactured by grinding together a mixture of 80 to 85 % of the granulated slag, 10 to 15 % of the hard burnt gypsum, and 5% Portland cement clinker. This cement is high sulphate resistant. Because of this property it is used for the Foundation where chemically aggressive condition exists.

Low heat cement

Hydration of the cement is exothermic process which liberates high quantity of the heat. This will cause the formation of the cracks. A low heat evolution is brought by Reducing the C3A and C3S which are the compounds evolving the greater heat of hydration and increasing C2S. Rate of evolution of heat of hydration will therefore will be less and evolution of heat will extend over a large period. Therefore Low heat cement rate of the development of the strength is very low. Used for the mass construction works

Portland Pozzolona cement

Portland Pozzolona cement is manufactured by intergrinding OPC clinker with 10 to 25% of the Pozzolona material. Portland Pozzolona cement produces low heat of hydration and offer greater resistance to the attack of the aggressive water than OPC. Used for the mass construction works, marine and hydraulic works.

Air entraining cement

This cement is manufactured by mixing small amount of the air entraining agent with the OPC clinker at the time of grinding. At the time of mixing this cement will produce air bubbles in the body of the concrete which will modify the properties of the plastic concrete with respect to the workability, segregation and bleeding

Coloured cement

Coloured cement consists of the Portland cement with the 5 to 10 % of the pigment. The cement and the pigment is grinded together.

Hydrophobic cement

This cement is manufactured by grinding the OPC clinker with the water repellent film forming substance. The water repellent film formed around each grain of the cement reduces the deterioration of the cement during the long storage, transportation and unfavorable conditions. Water repellent film formed will also improve the workability

Expansive cement

Concrete formed using the OPC shrinks during the setting due to the loss of the water. In grouting works if concrete shrinks the purpose for which the grout is used will be to some extend defeated. A slight expansion with time is advantageous for the grouting works. This type of the cement which does not suffer an overall change in the volume on drying is known as the Expansive cement. This cement is manufactured by using an expansive agent and a stabilizer.