Bricks and blocks Types of bricks Bricks are
Bricks and blocks
Types of bricks �Bricks are usually laid flat and are usually bonded forming a structure to increase its stability and strength. There are several types of bricks used many of them being about eight inches long and four inches thick.
Cont’d. . bricks There are various types of bricks �Common burnt clay bricks �Sand lime bricks(calcium silicate bricks) �Engineering bricks �Concrete bricks �Fly ash clay bricks
Common burnt clay bricks � 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 � 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 loadbearing member.
Engineering bricks �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 �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 �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.
Bricks advantages � 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. 1.
3. 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. 4. Fire Resistance - When prepared properly a brick structure can give a fire protection maximum rating of 6 hours. 5. 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. 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. 8. Efflorescence - Efflorescence forms on concrete structures and surfaces when soluble salts dissolved in water are deposited and accumulated on surfaces forming a visible scum. 9.
Manufacturing process 1. Brick is made of clay or shale formed, dried and fired into a durable ceramic product. 2. There are three ways to form the shape and size of a brick: extruded (stiff mud), moulded (soft mud) and dry- pressed. The majority of brick are made by the extrusion method. 3. Brick achieves its colour through the minerals in the fired clay or through coatings that are applied before or after the firing process. This provides a durable colour that never fades or diminishes.
4. Brick shrink during the manufacturing process as vitrification occurs. Brick will vary in size due to the manufacturing process. These variations are addressed by ASTM standards. 5. The method used to form a brick has a major impact on its texture. Sand-finished surfaces are typical with moulded brick. A variety of textures can be achieved with extruded brick. 6. Brick manufacturers address sustainability by locating manufacturing facilities near clay sources to reduce transportation, by recycling of process waste, by reclaiming land where mining has occurred, and by taking measures to reduce plant emissions. Most brick are used within 500 miles of a brick manufacturing facility.
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Concrete blocks � 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
�Most commonly used concrete blocks are sized: �Length: 40 cm (half blocks: 20 cm) �Height: 20 cm �Width: 8/10/15/20 cm
Types of concrete blocks �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. �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 �High compressive strength, resistance to weathering, impact and abrasion �Capability of being moulded into components of any shape and size �Good fire resistance up to about 400°C �Rapid construction �Very good stability
Technical advantages - Hollow blocks: �Can be made larger than solid blocks �Are lighter in weight �Construction of walls is easy and quick �The voids can be filled with steel bars and concrete, achieving high earthquake resistance �The air space provides good thermal insulation �The cavities can be used for electrical installation and plumbing
Economic advantages � Production can be started with little capital. � Less working time required for brick laying work with concrete blocks. � Less mortar consumption � Generally, production costs of concrete blocks are slightly lower than of fired bricks.
Limits of application �Raw materials must be locally available, of good quality and economically viable. �Relatively large amount of cement is needed, which can be expensive and difficult to obtain. �Special knowledge and experience of the production process is needed
Raw material Cement: � Ordinary Portland Cement � Special cements Aggregate: � Sand or gravel � Max. particle size of coarser aggregates is 10 mm. � Suitable aggregates are usually obtained from natural sources (river beds, gravel pits, volcanic deposits) or from industrial by-processes (granulated blast furnace slag, sintered fly ash).
Cement-Aggregate Ratio: � Suitable proportion of aggregate to cement must be found by testing � Common ratios are 1: 6, 1: 8 � Test the quality of blocks produced Water-Cement Ratio: � Only drinking quality water should be used to mix the concrete. � Recommended water-cement ratio is 0. 5
Production process Batching and mixing: �Batch aggregates and cement by weight. �Mix cement and aggregates using mattock, shovel or mixer until it reaches homogeneous condition �Add some water �In hot climates, the fresh mix must be shaded from the sun
Moulding: �Put the mixture into wooden or steel mould boxes or moulding machine. �Demould blocks immediately after compaction Curing: �Cover demoulded blocks with plastic sheets for 24 hrs. �Keep the concrete blocks moist by keeping under water in tanks or by regularly spraying with water for 7 days.
Storing: �Do not expose to direct sun light; keep the blocks in a dry and covered area. �Store for 2 weeks before usage. �http: //www. youtube. com/watch? v=d. Um 59 rk 25 Yc �http: //www. youtube. com/watch? v=_S_ci. Jc. HE 7 g �http: //www. youtube. com/watch? v=_b. Ae. Tejr. P 88
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