Question

Q3/A: Define the following: (Choose Five Only). (15 marks) 1- Melting point 2- Calcinations 3- Magnesia lime 4- Cast iron 5- Durability 6- Porcelain tiles 7- White Portland Cements Q3/B: Compare between the following: (Choose Three Only) (15 marks) 1. Sand lime bricks and Clay bricks. 2. Plaster of Paris mortar and Quick lime mortar. 3. Marble tiles and Ceramic tiles. 4. Wrought iron and Mild steel. Q4/A: Answer Three Only. (15 marks) 1. Briefly describe the grades (types) of the local concrete blocks according to Iraqi standard. 2. Explain the steps of dry process of manufacturing of Portland cement. 3. The dry air charged with CO2, greatly accelerating the setting process of lime mortars, give the reasons. 4. Discuss in detail the effect of the heat and water content on gypsum.

Answer 1

MELTING POINT : melting point is that point or temperature at which state of substance change from solid to liquid. Every substance have different melting point. It's is depend upon the molecular attraction and molecular bonding of particle in substance.

CALCINATION :the heating of limestone to redness in contact with air is basically know as calcination.

CAST IRON: cast iron is an alloy of iron. Iron can be classified into different categories on basis of carbon content present. So if carbon percentage is more than 2% the is said to be cast iron. It is brittle in nature. Used in construction field and also for making urensiles.

DURABILITY : it is an kind of validity of material means like an expiry date. It is define as the ability to withstand wear and tear, external pressure, damages. How long lasting, endurance.

White Portland cement

White cement is the one having iron oxide content limited upto 1% and that is possible by using white clay or china clay

Limestone (Ca>95%) +(china clay <1%) buring gives white cement at 1200°c along with mixing cryolite

PART B

Sand lime brick

These brick are also know as calcium silicate brick because they are made up from sand and lime.

These brickvare used for ornamental work, masonary work, aesthetic appearance.

These brick comes in different colour due to mixing of pigments into bricks. These brick are dense smooth and hard

These brick unsuitable for foundation and paving work, poor water resistant and poor abrasion resistant.

These bricK widely used in Australia ,Europe ,Canada , India.

CLAY BRICK

These are the regular brick used in construction looking redish colour of standard size 19*9*9 cm

These brick made up of mixing Alumina 20% , silica, 55% , Lime 5% oxide of iron 5-6%.

These brick are suitable in foundation and paving work.

Low water absorption capacity, fire resistant. Frost resistant

2. MARBLE TILES

It is naturally occurring material , it is obtained from metamorphic rock.

Marble is available is variety of colur texture and shades depend upon Gelogical formation.

Marble is a naturally pollished finished material.

It's strength and density is very high. High water resistant

CEREMIC TILES

ceremic tile are made by buring clay and silicates at high temperature.

Ceremic tiles available in quarry tiles, Terra cota, porcelain.

It is available in both form glazed and Unglazed.

Density and water resistant is low compare to marble.

3. WROUGHT IRON

it is a purest form of iron, having carbon content is very low 0.15%

It is produced in furnance

It is highly refined with small amount of salag forged.

Presence of alag help in blacksmithing.

Corrosion protection and less fatigue effect

MILD STELL

It is an low carbon steel or soft steel

It is malleable, ductile, tough, and more elastic than wrought iron.

It can be forged and weld

It rusts quickly and can be magnetized PARMANTELY.

Carbon content is 0.25%

Que 4

Dry process

It is a new method of manufacturing

Fuel and power consumption is reduced to great extent.

Calcurous matorial Argilla cows madoricu Crushing Crushing grinding in Tube mills in Tube miles Storago Basin Parinding Storage Basin Mixed In Correct proporting | Prenodiging @ 800°C Storage tanie 1 Fed to Rotary klin 1 Clinkers formed Addition of 2 to 34 ty Clinker ground In Ball mill gypsum Camoul Sillos I Baricing Plant

Effect of water content on gypsum

Gypsum Casou 2 H2O 110-130°C 130-200°C > Casou at H₂O Plaster of paris homi hydrated 200-1100C Casoy > (Anhydrated) > / Fast Casoy Jession + H₂O <4000