EAT 258 BUILDING MATERIAL ENGINEERING exclusive by MOHD

EAT 258 BUILDING MATERIAL ENGINEERING exclusive by MOHD EKHWAN BIN RAZALI

BRICKS AND BLOCKS u. DESCRIBE and DISCUSS type of bricks; Manufacturing process; DESCRIBE and DISCUSS type of concrete blocks

BRICKS u. A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote any rectangular units laid in mortar. A brick can be composed of clay-bearing soil, sand, and lime, or concrete materials. Bricks are produced in numerous classes, types, materials, and sizes which vary with region and time period, and are produced in bulk quantities. Two basic categories of bricks are fired and non-fired bricks.

There are various types of bricks u Common u Sand burnt clay bricks lime bricks(calcium silicate bricks) u Engineering u Concrete u Fly bricks ash clay bricks

Common burnt clay bricks u Common burnt clay bricks are formed by pressing in moulds. Then these bricks are dried and fired in a kiln. Common burnt clay bricks are used in general work with no special attractive appearances. When these bricks are used in walls, they require plastering or rendering.

Sand Lime Bricks u Sand lime bricks are made by mixing sand, fly ash and lime followed by a chemical process during wet mixing. The mix is then molded under pressure forming the brick. These bricks can offer advantages over clay bricks such as: 1. Their colour appearance is grey instead of the regular reddish colour. 2. Their shape is uniform and presents a smoother finish that doesn’t require plastering. 3. These bricks offer excellent strength as a load-bearing member.

Engineering bricks u. Engineering bricks are bricks manufactured at extremely high temperatures, forming a dense and strong brick, allowing the brick to limit strength and water absorption. Engineering bricks offer excellent load bearing capacity damp-proof characteristics and chemical resisting properties.

Concrete Bricks u. Concrete bricks are made from solid concrete. Concrete bricks are usually placed in facades, fences, and provide an excellent aesthetic presence. These bricks can be manufactured to provide different colours as pigmented during its production.

Fly Ash Clay Bricks u Fly ash clay bricks are manufactured with clay and fly ash, at about 1, 000 degrees C. Some studies have shown that these bricks tend to fail poor produce pop-outs, when bricks come into contact with moisture and water, causing the bricks to expand.

Modern Brick Manufacturing Process u. The manufacture of clay requires a 7 step manufacturing process. 1. Winning and storage 2. Processing the raw materials 3. Forming the bricks 4. Drying 5. Glazing(if required) 6. Burning and Cooling 7. Drawing and Storage

WINNING AND STORAGE u Winning is a term used to describe the mining of clay and most bricks made from surface-mined clay u Fireclays u Moved are obtained from underground mines by truck or rail to plant.

PROCESSING THE RAW MATERIALS u Clays blended to produce the desired chemical composition and physical properties u Blended clay are then moved to crushers where stones are removed and the clay lumps reduced to 50 mm (D) u Then moved by conveyor to grinders where it is ground to a fine powder and passed over vibrating screens. u If the materials too large to go through the screens send back to grinder u Only fine materials is placed in Storage.

FORMING THE BRICKS u Three major methods forming the bricks v Soft-mud process v The stiff-mud process v The dry press process

Soft-mud process u Is used for brick making from clays having too much natural water to permit the use of the stiff process. u The bricks are shaped in molds lubricated with water and sands. § Water-struck – bricks have a relatively smooth § Sand-struck – bricks have matte textured surface

Stiff-mud process u Most widely used. It is a high-production procedure that passes clay of 12 – 15 percent moisture through vaccum to remove air u Forced by auger through a die, producing a continuous column of the desired size and shape. u Only perfect bricks are placed on drier cars for transfer to a drier kiln. o/w

Dry-press process u Used u Mix clay having 10 percent or less moisture formed into bricks in steel molds under high pressure

DRYING u Once formed, the bricks are placed in low temperature drier kiln for one to two days. u The temperature and humidity are carefully controlled to prevent rapid shrinkage and possible cracking.

GLAZING u Bricks have a ceramic glaze applied to one or more surface after the brick has been dried. u Glaze is a sprayed coating of mineral ingredients that melts and fuses to the brick when subjected to the required temperature. u The glaze forms a smooth, glasslike coating and its available in a wide range od colours

BURNING AND COOLING u Burning u Involves raising the temperature of dried bricks to a predetermined level. u Two types kilns used Periodic kiln & Tunnel kiln u Periodic kiln is filled with bricks stacked so air can circular between them u Tuneel kiln is a long, narrow strucures through which bricks move on cars

u The bricks enter the kiln on one end are fired and cooled as they move through to the others u The burning process for both methods takes from 40 to 150 hours, depending on desired end results u The burning process itself involves several stages; Watersmoking, Dehydration, Oxidation, Vitrification, Flashing and Cooling

Water-smoking u Removes free water by evaporation and requires temperatures up to 204 o. C.

Dehydration u Removes additional moisture and requires temperatures ranging from 150 to 980 o. C.

Oxidation u Temperatures range from 540 – 980 o. C

Vitrification u From 870 – 1315 o. C. These last processes transform clay into a solid, ceramic materials.

Flashing u If required, follows at this point. It is accomplished by adjusting the fire to reduce the atmosphere in the kiln. u Reduces a variation in the colors and color shading of thr bricks.

Cooling u Forty-eight u Rate to seventy-two hours begins of coolong affects a bricks color and control cracking and checking.

DRAWING AND STORAGE u After the cooling stage is complete, bricks are removed from kiln, sorted, graded, and moved to storage. u Stacked on wood pallets for loading by forklift. Each pallet loads is wrapped in plastic to keep the bricks dry.

ASSIGNMENT 1 u Explain the process (Details) and differentiate the manufacturing process for Engineering bricks and Concrete Bricks. u Duedate: u Marks: Week 13, Friday, 19 May 2017 5%

Bricks advantages u 1. There are many advantages when bricks are used as part of the construction. The following list presents some of the most common advantages when using bricks instead of other construction materials. Aesthetic -Bricks offer natural and a variety of colours, including various textures. 1. Strength -Bricks offer excellent high compressive strength.

3. - 4. Durability Brick is extremely durable and perhaps is the most durable man-made structural building material so far. Porosity - The porosity of bricks in attributed to its fine capillaries. The ability to release and absorb moisture is one of the most important and useful properties of bricks, regulating temperatures and humidity inside structures. 5. Fire Resistance - When prepared properly a brick structure can give a fire protection maximum rating of 6 hours. 6. - Sound Insulation The brick sound insulation is normally 45 decibels for a 4. 5 inches brick thickness and 50 decibels for a nine inch thick brick.

7. - 8. Insulation Bricks can exhibit above normal thermal insulation when compared to other building materials. Bricks can help regulate and maintain constant interior temperatures of a structure due to their ability to absorb and slowly release heat. This way bricks can produce significant energy savings, more than 30% of energy saving, when compared to wood. Wear - A brick is so strong, that its molecular composition provides excellent wear resistance. 9. Efflorescence - Efflorescence forms on concrete structures and surfaces when soluble salts dissolved in water are deposited and accumulated on surfaces forming a visible scum.

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BLOCKS u Block is a similar term referring to a rectangular building unit composed of similar materials, but is usually larger than a brick. Lightweight bricks (also called lightweight blocks) are made from expanded clay aggregate.

Concrete blocks u Concrete block construction has gained importance and has become a valid alternative to fired clay bricks. The essential ingredients of concrete are cement, aggregate (sand, gravel) and water. Concrete blocks are produced in a large variety of shapes and sizes. They can be produced manually or with the help of machines

u Most commonly used concrete blocks are sized: u Length: 40 cm (half blocks: 20 cm) u Height: 20 cm u Width: 8/10/15/20 cm

Types of concrete blocks u Solid blocks have no cavities, or- according to US standards- have no voids amounting to not more than 25% of the gross cross-sectional area. u Hollow blocks are the most common type of concrete blocks, having one or more holes that are open at both sides. The total void area can amount to 50% of the gross cross-sectional area.

Technical advantages - Solid blocks u High compressive strength, resistance to weathering, impact and abrasion u Capability size of being moulded into components of any shape and u Good fire resistance up to about 400°C u Rapid construction u Very good stability

Technical advantages - Hollow blocks: u Can u Are be made larger than solid blocks lighter in weight u Construction of walls is easy and quick u The voids can be filled with steel bars and concrete, achieving high earthquake resistance u The air space provides good thermal insulation u The cavities can be used for electrical installation and plumbing

Economic advantages u Production can be started with little capital. u Less working time required for brick laying work with concrete blocks. u Less mortar consumption u Generally, production costs of concrete blocks are slightly lower than of fired bricks.

Limits of application u Raw materials must be locally available, of good quality and economically viable. u Relatively large amount of cement is needed, which can be expensive and difficult to obtain. u Special needed knowledge and experience of the production process is

Raw material Cement: u Ordinary u Special Portland Cement cements Aggregate: u Sand or gravel u Max. particle size of coarser aggregates is 10 mm. u Suitable aggregates are usually obtained from natural sources (river beds, gravel pits, volcanic deposits) or from industrial byprocesses (granulated blast furnace slag, sintered fly ash).

Cement-Aggregate Ratio: u Suitable proportion of aggregate to cement must be found by testing u Common ratios are 1: 6, 1: 8 u Test the quality of blocks produced Water-Cement Ratio: u Only drinking quality water should be used to mix the concrete. u Recommended water-cement ratio is 0. 5

Production process Batching and mixing: u Batch aggregates and cement by weight. u Mix cement and aggregates using mattock, shovel or mixer until it reaches homogeneous condition u Add u In some water hot climates, the fresh mix must be shaded from the sun

Moulding: u. Put the mixture into wooden or steel mould boxes or moulding machine. u. Demould blocks immediately after compaction Curing: u Cover u Keep demoulded blocks with plastic sheets for 24 hrs. the concrete blocks moist by keeping under water in tanks or by regularly spraying with water for 7 days.

Storing: u. Do not expose to direct sun light; keep the blocks in a dry and covered area. u. Store for 2 weeks before usage. uhttp: //www. youtube. com/watch? v=d. Um 59 rk 25 Yc uhttp: //www. youtube. com/watch? v=_S_ci. Jc. HE 7 g uhttp: //www. youtube. com/watch? v=_b. Ae. Tejr. P 88