Brick

 **2 Open a //brick// page in your wi**ki and answer the following questions (you can do a search on the Web): The raw material is a clay brick, which must have the following chemical composition to be suitable for a brick:
 * What are they made of?


 * Alkalis** and acids content: less than 0.2%. It can cause efflorescence with a higher percentage.
 * Soluble substances** (salts: saódico sulfate, magnesium sulfate): less than 0.04%. Same as above produces a higher percentage eflorecencias Pyrites (iron sulfides). Its excess sulfuric deposition may occur at the time of cooking, causing undesirable coloration and cracks on the material.
 * Alumina content:** 20% - 30%: provides plasticity to the clay, and a high excess causes contraction on drying.
 * Silica content**: 50% - 60%: Gives low shrinkage, prevents cracking, uniform forms provided to the brick. Associated with durability. Its excess decreases the cohesion between particles.
 * Iron Oxide:** provides a reddish pottery, producing lime prevents the function of the sand. Its excess produces a dark blue color (usually does not cause other discomfort). **Cal:** You must be dispersed (diameter 0.2 mm) or more lime water. Is a flux which allows to lower the melting temperature of silica. If there is too much causing cracking can melt and deformation of the workpiece. MgO: Imparts yellow color to ceramic. Help to decrease the deformation. I know too much deterioration occurs by expansion of the surface. Furthermore, the clay must have a low content of organic material so that in the baking process there are no gaps by the use of this material.

Bricks are used for building, [|block paving] and [|pavement]. In the USA, brick pavement was found incapable of withstanding heavy traffic, but it is coming back into use as a method of [|traffic calming] or as a decorative surface in [|pedestrian precincts]. For example, in the early 1900s, most of the streets in the city of [|Grand Rapids], [|Michigan] were paved with brick. Today, there are only about 20 blocks of brick paved streets remaining (totalling less than 0.5 percent of all the streets in the city limits). [|[17]] Bricks in the [|metallurgy] and [|glass] industries are often used for lining [|furnaces], in particular [|refractory] bricks such as [|silica] , [|magnesia] , [|chamotte] and neutral ( [|chromomagnesite] ) [|refractory bricks]. This type of brick must have good [|thermal shock] resistance, [|refractoriness] under load, high melting point, and satisfactory [|porosity]. There is a large refractory [|brick industry], especially in the [|United Kingdom] , [|Japan] , the [|United States] , [|Belgium] and the [|Netherlands]. In Northwest Europe, bricks have been used in construction for centuries. Until recently, almost all houses were built almost entirely from bricks. Although many houses are now built using a mixture of [|concrete blocks] and other materials, many houses are skinned with a layer of bricks on the outside for aesthetic appeal.
 * What are they used for?

Types of brick According to their shape, the bricks are classified as: Perforated brick, which are all those with perforations in the table that cover more than 10% of the surface thereof. Are used in implementing the brick facade. Solid brick, those with less than 10% of perforations in the table. Some models have a recess in the tables and heads to the walls without running sores. Brick, tile or manual, simulating the old handmade bricks, looking rough and wrinkled faces. Have good properties ornamentals. Moulded brick, one that has a curved profile, so that by placing a row of brick rowlock generally, form a molding run. The name comes from the templates used by the masons to carve the stones, and used to give that form to the brick. Hollow brick are those that have slots on the song or the head to reduce weight and volume of material used in them, making it easier to cut and handle. Those with horizontal holes are used to partition that will not withstand heavy loads. Can be of several types: Rasilla: his rope and blight are much larger than its thickness. In Spain, their common dimensions are 24 x 11.5 x 2.5 cm. Hollow brick simple: it has a row of holes in the head. Hollow brick double with two rows of holes in the head. Hollow brick triple: three rows of holes in the head. Facing Brick: those that are used outdoors with a special finish. Refractory brick: is placed in places where it must withstand high temperatures, such as stoves or fireplaces.
 * How many types of brick are there?

They are collecting thousands of years of trial and error that allowed the improvement and development of architecture and other fields related to construction.
 * What is the meaning of brick laying techniques?

Rigging is the law of locking arrangement of the bricks in a wall, which provides from the dimensions of the wall to meetings and enjarjes, so that the wall up evenly across the entire height of the building. Some types of gear are:
 * Describe 2 brick laying techniques


 * Rig ropes**: the sides of the wall formed by the ropes of brick, has a thickness of half a foot (the header) and is widely used for face brick facades.


 * Rig English**: in this case alternating brick and blight rope, locking the sore raw brick, giving a thickness of 1 foot (the rope). It is widely used for bearing walls in face brick facades. Your lock is better than the tailings wall but put into play is more complicated and requires more experienced workforce. The drawing does not correspond to the type of rig.




 * What are their advantages and disadvantages?

Advantages

--One of the biggest advantages of brick is that it does not rust like metal structures and tempo can last much longer even if it rains continuously. --Since it is a ceramic product in the cooking process, more than 1000 ° C, the input machining it special characteristics which support all types of weather conditions. ---Thermal Resistance: In every work built by bricks inside, you feel a comfortable temperature on the outside, unlike other materials. --Impermeability: Because the bricks have smooth faces and polished, in most prevent the passage of liquid possible, besides not disintegrate in water.

Disadvantages

--Are not structurally flexible compared to metal structures. --Usually the brick is usually more expensive than other materials.





3. ** Listening/reading activity. ** Listen to the ** [|podcast] ** and ** reply with your thoughts on the use of brick in construction and public spaces. Post your reply to your wiki page and record it. **

As pointed out by Gladys Baya, the brick has been an important construction material for human being. It is present in almost all structures of antiquity and post it. The reason for this is that the brick is a very cheap, easy to produce and easy to mold. Thus we see the presence of brick structures like monasteries, theaters, walls, seats, etc.. All have something in common: almost all these works have withstood the storms of weather and climate and characterized by its enormous strength. But now the brick is not a material as used as in previous centuries. The reason is that scientific discoveries have given man new media options. For example, we can now use metal and steel to build large structures stronger, lighter and stronger than brick. With the use of brick would have been impossible to create big and tall skyscrapers, structures are made mostly of steel.

But it is true that in our time not used as much brick as before, the fact remains that the brick is still used for housing and decorate the exterior walls of houses.   media type="file" key="podcast_brick.wma" align="center"