brick

1. pl., bricks, or brick. A molded rectangular block of clay baked by the sun or in a kiln until hard and used as a building and paving material.
2. An object shaped like such a block: a brick of cheese.
3. Informal. A helpful, reliable person.

1. To construct, line, or pave with bricks.
2. To close or wall with brick: bricked up the windows of the old house.

drop a brick Informal.

1. To make a clumsy social error.

[Middle English brike, from Middle Dutch bricke.]

Background

The term brick refers to small units of building material, often made from fired clay and secured with mortar, a bonding agent comprising of cement, sand, and water. Long a popular material, brick retains heat, with-stands corrosion, and resists fire. Because each unit is small—usually four inches wide and twice as long, brick is an ideal material for structures in confined spaces, as well as for curved designs. Moreover, with minimal upkeep, brick buildings generally last a long time.

For the above-cited practical reasons and because it is also an aesthetically pleasing medium, brick has been used as a building material for at least 5,000 years. The first brick was probably made in the Middle East, between the Tigris and Euphrates rivers in what is now Iraq. Lacking the stone their contemporaries in other regions used for permanent structures, early builders here relied on the abundant natural materials to make their sun-baked bricks. These, however, were of limited use because they lacked durability and could not be used outdoors; exposure to the elements caused them to disintegrate. The Babylonians, who later dominated Mesopotamia, were the first to fire bricks, from which many of their tower-temples were constructed.

From the Middle East the art of brickmaking spread west to what is now Egypt and east to Persia and India. Although the Greeks, having a plentiful supply of stone, did not use much brick, evidence of brick kilns and structures remains throughout the Roman Empire. However, with the decline and fall of Rome, brickmaking in Europe soon diminished. It did not resume until the 1200s, when the Dutch made bricks that they seem to have exported to England. In the Americas, people began to use brick during the sixteenth century. It was the Dutch, however, who were considered expert craftsmen.

Prior to the mid-1800s, people made bricks in small batches, relying on relatively inefficient firing methods. One of the most widely used was an open clamp, in which bricks were placed on a fire beneath a layer of dirt and used bricks. As the fire died down over the course of several weeks, the bricks fired. Such methods gradually became obsolete after 1865, when the Hoffmann kiln was invented in Germany. Better suited to the manufacture of large numbers of bricks, this kiln contained a series of compartments through which stacked bricks were transferred for pre-heating, burning, and cooling.

Brickmaking improvements have continued into the twentieth century. Improvements include rendering brick shape absolutely uniform, lessening weight, and speeding up the firing process. For example, modern bricks are seldom solid. Some are pressed into shape, which leaves a frog, or depression, on their top surface. Others are extruded with holes that will later expedite the firing process by exposing a larger amount of surface area to heat. Both techniques lessen weight without reducing strength.

However, while the production process has definitely improved, the market for brick has not. Brick does have the largest share of the opaque materials market for commercial building, and it continues to be used as a siding material in the housing industry. However, other siding materials such as wood, stucco, aluminum, plaster, and vinyl are strong competitors because they cost up to 50 percent less, and some (notably stucco and plaster) offer built-in insulation. Yet these systems can cost up to 1.75 times that of brick, which also requires less maintenance. Other materials that compete with brick despite their usually higher cost include precast concrete panels, glass, stone, artificial stone, concrete masonry, and combinations of these materials, because advances in manufacturing and design have made such materials more attractive to the builder. According to the U.S. Industrial Outlook, the use of brick as a siding material for single-family homes dropped from 26 percent in 1984 to 17 percent in 1989.

Raw Materials

Natural clay minerals, including kaolin and shale, make up the main body of brick. Small amounts of manganese, barium, and other additives are blended with the clay to produce different shades, and barium carbonate is used to improve brick's chemical resistance to the elements. Many other additives have been used in brick, including byproducts from papermaking, ammonium compounds, wetting agents, flocculents (which cause particles to form loose clusters) and deflocculents (which disperse such clusters). Some clays require the addition of sand or grog (pre-ground, pre-fired material such as scrap brick).

A wide variety of coating materials and methods are used to produce brick of a certain color or surface texture. To create a typical coating, sand (the main component) is mechanically mixed with some type of colorant. Sometimes a flux or frit (a glass containing colorants) is added to produce surface textures. The flux lowers the melting temperature of the sand so it can bond to the brick surface. Other materials including graded fired and unfired brick, nepheline syenite, and graded aggregate can be used as well.

The Manufacturing
Process

The initial step in producing brick is crushing and grinding the raw materials in a separator and a jaw crusher. Next, the blend of ingredients desired for each particular batch is selected and filtered before being sent on to one of three brick shaping processes—extrusion, molding, or pressing, the first of which is the most adaptable and thus the most common. Once the bricks are formed and any subsequent procedures performed, they are dried to remove excess moisture that might otherwise cause cracking during the ensuing firing process. Next, they are fired in ovens and then cooled. Finally, they are dehacked—automatically stacked, wrapped with steel bands, and padded with plastic corner protectors.

Grinding, sizing, and combining
raw materials

• First, each of the ingredients is conveyed to a separator that removes oversize material. A jaw crusher with horizontal steel plates then squeezes the particles, rendering them still smaller. After the raw materials for each batch of bricks have been selected, a scalping screen is often used to separate the different sizes of material. Material of the correct size is sent to storage silos, and over-sized material goes to a hammermill, which pulverizes it with rapidly moving steel hammers. The hammermill uses another screen to control the maximum size of particle leaving the mill, and discharge goes to a number of vibrating screens that separate out material of improper size before it is sent on to the next phase of production.

Extrusion

• With extrusion, the most common method of brick forming, pulverized material and water are fed into one end of a pug mill, which uses knives on a rotating shaft to cut through and fold together material in a shallow chamber. The blend is then fed into an extruder at the far end of the mill. The extruder usually consists of two chambers. The first removes air from the ground clay with a vacuum, thereby preventing cracking and other defects. The second chamber, a high-pressure cylinder, compacts the material so the auger can extrude it through the die. After it is compressed, the plastic material is forced out of the chamber though a specially shaped die orifice. The cross-section of the extruded column, called the "pug," is formed into the shape of the die. Sections of desired length are cut to size with rotating knives or stiff wires.

  In molding, soft, wet clay is shaped in a mold, usually a wooden box. The interior of the box is often coated with sand, which provides the desired texture and facilitates removing the formed brick from the mold. Water can also be used to assist release. Pressing, the third type of brick forming, requires a material with low water content. The material is placed in a die and then compacted with a steel plunger set at a desired pressure. More regular in shape and sharper in outline than brick made with the other two methods, pressed bricks also feature frogs.

Chamfering the brick

• Chamfering machines were developed to produce a furrow in brick for such applications as paving. These machines use rollers to indent the brick as it is being extruded. They are sometimes equipped with wire cutters to do the chamfering and cutting in one step. Such machines can produce as many as 20,000 units per hour.

Coating

• The choice of sand coating, also applied as the brick is extruded, depends on how soft or hard the extruded material is. A continuous, vibrating feeder is used to coat soft material, whereas for textured material the coating may have to be brushed or rolled on. For harder materials a pressure roller or compressed air is used, and, for extremely hard materials, sand blasting is required.

Drying

• Before the brick is fired, it must be dried to remove excess moisture. If this moisture is not removed, the water will burn off too quickly during firing, causing cracking. Two types of dryers are used. Tunnel dryers use cars to move the brick through humidity-controlled zones that prevent cracking. They consist of a long chamber through which the ware is slowly pushed. External sources of fan-circulated hot air are forced into the dryer to speed the process.
• Automatic chamber dryers are also used, especially in Europe. The extruded bricks are automatically placed in rows on two parallel bars. The bricks are then fed onto special racks with finger-like devices that hold several pairs of bars in multiple layers. These racks are then transferred by rail-mounted transfer cars or by lift trucks into the dryers.

Firing

• After drying, the brick is loaded onto cars (usually automatically) and fired to high temperatures in furnaces called kilns. In general, the cars that moved the bricks through the drying process are also used to convey them through the tunnel kiln. These cars are pushed through the kiln's continuously maintained temperature zones at a specific rate that depends on the material. The majority of kilns in the United States use gas as a fuel source, though a third of the brick currently produced is fired using solid fuels such as sawdust and coal. Tunnel kilns have changed in design from high-load, narrow-width kilns to shorter, lower-set wider kilns that can fire more brick. This type of design has also led to high-velocity, long-flame, and low-temperature flame burners, which have improved temperature uniformity and lowered fuel consumption.

Setting and packaging

• After the brick is fired and cooled, it is unloaded from the kiln car via the dehacking process, which has been automated to the point where almost all manual brickhandling is eliminated. Automated setting machines have been developed that can set brick at rates of over 18,000 per hour and can rotate the brick 180 degrees. Usually set in rows eleven bricks wide, a stack is wrapped with steel bands and fitted with plastic strips that serve as corner protectors. The packaged brick is then shipped to the job site, where it is typically unloaded using boom trucks.

Quality Control

Though the brick industry is often considered unsophisticated, many manufacturers are participating in total quality management and statistical control programs. The latter involves establishing control limits for a certain process (such as temperature during drying or firing) and tracking the parameter to make sure the relevant processes are kept within the limits. Therefore, the process can be controlled as it happens, preventing defects and improving yields.

A variety of physical and mechanical properties must be measured and must comply with standards set by the American Society of Testing and Materials (ASTM). These properties include physical dimensions, density, and mechanical strength. Another important property is freeze-thaw durability, where the brick is tested under conditions that are supposed to simulate what is encountered in the outdoors. However, current tests are inadequate and do not really correlate to actual conditions. What passes in the laboratory may not pass in the field. Therefore, the brick industry is trying to develop a more accurate test.

A similar problem exists with a condition known as efflorescence, which occurs when water dissolves certain elements (salt is among the most common) in exterior sources, mortar, or the brick itself. The residual deposits of soluble material produce surface discoloration that can be worsened by improper cleaning. When salt deposits become insoluble, the efflorescence worsens, requiring extensive cleaning. Though a brick may pass the laboratory test, it could fail in the field due to improper design or building practices. Therefore, brick companies are developing their own in-house testing procedures, and research is continuing to develop a more reliable standard test.

The Future

Currently, the use of brick has remained steady, at around seven to nine billion a year, down from the 15 billion used annually during the early 1900s. In an effort to increase demand, the brick industry continues to explore alternative markets and to improve quality and productivity. Fuel efficiency has also improved, and by the year 2025 brick manufacturers may even be firing their brick with solar energy. However, such changes in technology will occur only if there is still a demand for brick.

Even if this demand continues, the brick industry both here and abroad faces another challenge: it will soon be forced to comply with environmental regulations, especially in the area of fluorine emissions. Fluorine, a byproduct of the brickmaking process, is a highly reactive element that is dangerous to humans. Long-term exposure can cause kidney and liver damage, digestive problems, and changes in teeth and bones, and the Environmental Protection Agency (EPA) has consequently established maximum exposure limits. To lessen the dangers posed by fluorine emissions, brickworks can install scrubbers, but they are expensive. While some plants have already installed such systems, the U.S. brick industry is trying to play a more important role in developing less expensive emissions testing methods and establishing emission limits. If the brick industry cannot persuade federal regulators to lower their requirements, it is quite possible that the industry could shrink in size, as some companies cannot afford to comply and will go out of business.

Where To Learn More

Books

Bender, Willi and Frank Handle. Brick and Tile Making. Bauverlag GmbH, 1985.

Jones, J. T. and M. F. Berard. Ceramics: Industrial Processing and Testing. Iowa State University Press, 1972.

Robinson, Gilbert C. Ceramics and Glasses. ASM International, 1992, pp. 943-950.

Periodicals

"Trends in Brick Plant Operations," The American Ceramic Society Bulletin. 1992, pp. 69-74.

Hall, Alvin. "Using Computer-Aided Manufacturing to Build Better Brick," The American Ceramic Society Bulletin. 1990, pp. 80-82.

Richards, Robert W. "Brick Manufacturing from Past to Present," The American Ceramic Society Bulletin. May, 1990, pp. 807-813.

Sheppard, Laurel M. "Making Brick and Meeting Regulations," The American Ceramic Society Bulletin. 1993.

"Lodge Lane Brickworks: A Breakthrough in the Reduction Firing of Bricks," Ziegelindustrie. September, 1992, pp. 344-341.

[Article by: L S. Millberg]

A construction material usually made of clay and extruded or molded as a rectangular block. Three types of clay are used in the manufacture of bricks: surface clay, fire clay, and shale. Adobe brick is a sun-dried molded mix of clay, straw, and water, manufactured mainly in Mexico and some southern regions of the United States. See also Clay.

The first step in manufacture is crushing the clay. The clay is then ground, mixed with water, and shaped. Then the bricks are fired in a kiln at approximately 2000°F (1093°C). Substances in the clay such as ferrous, magnesium, and calcium oxides impart color to the bricks during the firing process. The color may be uniform throughout the bricks, or the bricks may be manufactured with a coated face. The latter are classified as glazed, claycoat, or engobe.

The most commonly used brick product is known as facing brick. Decorative bricks molded in special shapes are used to form certain architectural details such as water tables, arches, copings, and corners.

An electronics device that has been damaged and rendered useless. In other words, "as useful as a brick." See iBricking.

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In addition to the idioms beginning with brick, also see drop a brick; hit the bricks; like a cat on a hot brick; like a ton of bricks; make bricks without straw; run into a stone (brick) wall.

1. A piece of equipment that has been programmed or configured into a hung, wedged,unusable state. Especially used to describe what happens to devices like routers or PDAs that run from firmware when the firmware image is damaged or its settings are somehow patched to impossible values. This term usually implies irreversibility, but equipment can sometimes be unbricked by performing a hard reset or some other drastic operation. Sometimes verbed: “Yeah, I bricked the router because I forgot about adding in the new access-list.”.

2. An outboard power transformer of the kind associated with laptops, modems, routers and other small computing appliances, especially one of the modern type with cords on both ends, as opposed to the older and obnoxious type that plug directly into wall or barrier strip.

For more information on brick, visit Britannica.com.

A solid masonry unit, usually of clay, molded into a rectangular shape while plastic, and then treated in a kiln at an elevated temperature to harden it, so as to give it mechanical strength and to provide it with resistance to moisture; after being removed from the kiln, the brick is said to be burnt, hard-burnt, kiln-burnt, fired, or hard-fired. Bricks laid lengthwise in a wall are called stretchers; bricks laid crosswise to a wall are called headers. Bricks differ in color, ranging from dark red to rose and salmon, and from pink to blue-black and purple, depending on the type of clay and on the temperature of the kiln in which they were burnt. Various types of patterns common in laying bricks are described under bond. The current American brick is typically about 8 inches (20.3 cm) long, 3³/4 inches (8.26 cm) wide, and 2¹/4 inches (5.7 cm) thick; other countries tend to produce bricks with their own standard dimensions. For specific types of brick, see adobe quemado, air brick, angle brick, arch brick, axed brick, brindled brick, building brick, bull stretcher, burnt brick, cant brick, capping brick, closer, common brick, compass brick, concrete brick, coping brick, cow-nose brick, dogleg brick, dog-tooth course, Dutch brick.

brick: nomenclature

Feed compacted into a solid mass weighing up to 2 lb. Bricks provide an alternative to pellets and have the advantage that they have to be eaten slowly.

For other uses, see Brick (disambiguation).

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (February 2008)

An old brick wall in English bond laid with alternating courses of headers and stretchers.

Bricked Front Street along the Cane River in historic Natchitoches, Louisiana

A brick is a block of ceramic material used in masonry construction, usually laid using mortar.

Contents 1 History 2 Methods of manufacture 2.1 Mud bricks 2.1.1 Rail kilns 2.1.2 Bull's Trench Kilns 2.2 Dry pressed bricks 2.3 Extruded bricks 2.4 Calcium silicate bricks 3 Influence on fired colour 4 Optimal dimensions, characteristics, and strength 5 Use 6 See also 7 Gallery 8 Notes 9 References 10 External links

History

The Roman Constantine Basilica in Trier, Germany, built in the 4th century with fired bricks as audience hall for Constantine I

The oldest shaped bricks found date back to 7,500 B.C.^{[citation needed]} They have been found in Çayönü, in the upper Tigris region, and in south east Anatolia close to Diyarbakir. Other more recent findings, dated between 7,000 and 6,395 B.C., come from Jericho and Catal Hüyük. From archaeological evidence, the inven­tion of the fired brick (as opposed to the consid­erably earlier sun-dried mud brick) is believed to have arisen in about the third millennium BC. Being much more resistant to cold and moist weather conditions, brick enabled the construction of permanent buildings in regions where the harsher climate precluded the use of mud bricks. Bricks have the added warmth benefit of storing heat energy from the sun during the day and continuing to release heat after sunset.

Examples of the civilizations who used mudbrick are the ancient Egyptians and the Indus Valley Civilization, where it was used exclusively. In particular, it is evident from the ruins of Buhen, Mohenjo-daro and Harappa.

The ancient Jetavanaramaya stupa in Anuradhapura, Sri Lanka is one of the largest brick structures in the world

The world's highest brick tower of St. Martin's Church in Landshut, Germany, completed in 1500

Malbork Castle, former Ordensburg of the Teutonic Order - biggest brick castle in the world

In Sumerian times offerings of food and drink were presented to "the Bone god," who was "rep­resented in the ritual by the first brick."^{[citation needed]} More recently, mortar for the foundations of the Hagia Sophia in Istanbul was mixed with "a broth of barley and bark of elm" and sacred relics, accom­panied by prayers, placed between every 12 bricks.^{[citation needed]}

The Romans made use of fired bricks, and the Roman legions, which operated mobile kilns, introduced bricks to many parts of the empire. Roman bricks are often stamped with the mark of the legion that supervised its production. The use of bricks in Southern and Western Germany, for example, can be traced back to traditions already described by the Roman architect Vitruvius.

In pre-modern China, brick-making was the job of a lowly and unskilled artisan, but a kiln master was respected as a step above the latter.^[1] Early descriptions of the production process and glazing techniques used for bricks can be found in the Song Dynasty carpenter's manual Yingzao Fashi, published in 1103 by the government official Li Jie, who was put in charge of overseeing public works for the central government's construction agency. The historian Timothy Brook writes of the production process in Ming Dynasty China (aided with visual illustrations from the Tiangong Kaiwu encyclopedic text published in 1637):

The brickwork of Shebeli Tower in Iran displays 12th century craftsmanship

...the kilnmaster had to make sure that the temperature inside the kiln stayed at a level that caused the clay to shimmer with the colour of molten gold or silver. He also had to know when to quench the kiln with water so as to produce the surface glaze. To anonymous laborers fell the less skilled stages of brick production: mixing clay and water, driving oxen over the mixture to trample it into a thick paste, scooping the paste into standardized wooden frames (to produce a brick roughly 42 cm long, 20 cm wide, and 10 cm thick), smoothing the surfaces with a wire-strung bow, removing them from the frames, printing the fronts and backs with stamps that indicated where the bricks came from and who made them, loading the kilns with fuel (likelier wood than coal), stacking the bricks in the kiln, removing them to cool while the kilns were still hot, and bundling them into pallets for transportation. It was hot, filthy work.^[2]

The idea of signing the worker's name on the brick and the place where it was made was not new to the Ming era and had little or nothing to do with vanity.^[3] As far back as the Qin Dynasty (221 BC–206 BC), the government required blacksmiths and weapon-makers to engrave their names onto weapons in order to trace the weapon back to them, lest their weapons should prove to be of a lower quality than the standard required by the government.^[4]

In the 12th century, bricks from Northern Italy were re-introduced to Northern Germany, where an independent tradition evolved. It culminated in the so-called brick Gothic, a reduced style of Gothic architecture that flourished in Northern Europe, especially in the regions around the Baltic Sea which are without natural rock resources. Brick Gothic buildings, which are built almost exclusively of bricks, are to be found in Denmark, Germany, Poland, and Russia.

During the Renaissance and the Baroque, visible brick walls were unpopular and the brickwork was often covered with plaster. It was only during the mid-18th century that visible brick walls regained some degree of popularity, as illustrated by the Dutch Quarter of Potsdam, for example.

Chile house in Hamburg, Germany

The transport in bulk of building materials such as brick over long distances was rare before the age of canals, railways, roads and heavy goods vehicles. Before this time bricks were generally made close to their point of intended use. It has been estimated that in England in the eighteenth century carrying bricks by horse and cart for ten miles (16 km) over the poor roads then existing could more than double their price.^{[citation needed]}

Bricks were often used, even in areas where stone was available, for reasons of speed and economy. The buildings of the Industrial Revolution in Britain were largely constructed of brick and timber due to the demand created. During the building boom of the nineteenth century in the eastern seaboard cities of Boston and New York, for example, locally made bricks were often used in construction in preference to the brownstones of New Jersey and Connecticut for these reasons.

The trend of building upwards for offices that emerged towards the end of the 19th century displaced brick in favour of cast and wrought iron and later steel and concrete. Some early 'skyscrapers' were made in masonry, and demonstrated the limitations of the material - for example, the Monadnock Building in Chicago (opened in 1896) is masonry and just seventeen stories high, the ground walls are almost 6 feet (1.8 m) thick, clearly building any higher would lead to excessive loss of internal floor space on the lower floors. Brick was revived for high structures in the 1950s following work by the Swiss Federal Institute of Technology and the Building Research Establishment in Watford, UK. This method produced eighteen story structures with bearing walls no thicker than a single brick (150–225 mm). This potential has not been fully developed because of the ease and speed in building with other materials, in the late-20th century brick was confined to low- or medium-rise structures or as a thin decorative cladding over concrete-and-steel buildings or for internal non-load bearing walls.

Methods of manufacture

Brick making at the beginning of the 20th century.

Bricks may be made from clay, shale, soft slate, calcium silicate, concrete, or shaped from quarried stone.

Clay is the most common material, with modern clay bricks formed in one of three processes - soft mud, dry press, or extruded.

In 2007 a new type of brick was invented, based on fly ash, a by-product of coal power plants.

Mud bricks

The soft mud method is the most common, as it is the most economical. It starts with the raw clay, preferably in a mix with 25-30% sand to reduce shrinkage. The clay is first ground and mixed with water to the desired consistency. The clay is then pressed into steel moulds with a hydraulic press. The shaped clay is then fired ("burned") at 900-1000 °C to achieve strength.

Rail kilns

Xhosa brickmaker at kiln near Ngcobo in the former Transkei in 2007.

In modern brickworks, this is usually done in a continuously fired tunnel kiln, in which the bricks move slowly through the kiln on conveyors, rails, or kiln cars to achieve consistency for all bricks. The bricks often have added lime, ash, and organic matter to speed the burning.

Bull's Trench Kilns

In India, brick making is typically a manual process. The most common type of brick kiln in use there are Bull's Trench Kiln (BTK), based on a design developed by British engineer W. Bull in the late nineteenth century.

An oval or circular trench, 6-9 meters wide, 2-2.5 meters deep, and 100-150 meters in circumference, is dug. A tall exhaust chimney is constructed in the centre. Half or more of the trench is filled with "green" (unfired) bricks which are stacked in an open lattice pattern to allow airflow. The lattice is capped with a roofing layer of finished brick.

In operation, new green bricks, along with roofing bricks, are stacked at one end of the brick pile; cooled finished bricks are removed from the other end for transport. In the middle the brick workers create a firing zone by dropping fuel (coal, [wood], oil, debris, etc) through access holes in the roof above the trench.

West face of Roskilde Cathedral in Roskilde, Denmark.

The advantage of the BTK design is a much greater energy efficiency compared with clamp or scove kilns. Sheet metal or boards are used to route the airflow through the brick lattice so that fresh air flows first through the recently burned bricks, heating the air, then through the active burning zone. The air continues through the green brick zone (pre-heating and drying them), and finally out the chimney where the rising gases create suction which pulls air through the system. The reuse of heated air yields savings in fuel cost.

As with the rail process above, the BTK process is continuous. A half dozen laborers working around the clock can fire approximately 15,000-25,000 bricks a day. Unlike the rail process, in the BTK process the bricks do not move. Instead, the locations at which the bricks are loaded, fired, and unloaded gradually rotate through the trench.^[5]

Dry pressed bricks

The dry press method is similar to mud brick but starts with a much thicker clay mix, so it forms more accurate, sharper-edged bricks. The greater force in pressing and the longer burn make this method more expensive.

Extruded bricks

With extruded bricks the clay is mixed with 10-15% water (stiff extrusion) or 20-25% water (soft extrusion). This is forced through a die to create a long cable of material of the proper width and depth. This is then cut into bricks of the desired length by a wall of wires. Most structural bricks are made by this method, as hard dense bricks result, and holes or other perforations can be produced by the die. The introduction of holes reduces the needed volume of clay through the whole process, with the consequent reduction in cost. The bricks are lighter and easier to handle, and have thermal properties different from solid bricks. The cut bricks are hardened by drying for between 20 and 40 hours at 50-150 °C before being fired. The heat for drying is often waste heat from the kiln.

Calcium silicate bricks

The raw materials for calcium silicate bricks include lime mixed with quartz, crushed flint or crushed siliceous rock together with mineral colourants. The materials are mixed and left until the lime is completely hydrated, the mixture is then pressed into moulds and cured in an autoclave for two or three hours to speed the chemical hardening. The finished bricks are very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick (and brick-layer). The bricks can be made in a variety of colours, white is common but pastel shades can be achieved.

It is very common in Sweden, especially in houses built or renovated in the '70s. Here it is referred to as "Mexitegel" (en: Mexi[can] Bricks).

Influence on fired colour

The fired colour of clay bricks is influenced by the chemical and mineral content of raw materials, the firing temperature and the atmosphere in the kiln. For example pink coloured bricks are the result of a high iron content, white or yellow bricks have a higher lime content. Most bricks burn to various red hues, if the temperature is increased the colour moves through dark red, purple and then to brown or grey at around 1300 °C. Calcium silicate bricks have a wider range of shades and colours, depending on the colourants used. The names of bricks may reflect their origin and colour, such as London Red and Cambridgeshire White.

Bricks formed from concrete are usually termed blocks, and are typically pale grey in colour. They are made from a dry, small aggregate concrete which is formed in steel moulds by vibration and compaction in either an "egglayer" or static machine. The finished blocks are cured rather than fired using low-pressure steam. Concrete blocks are manufactured in a much wider range of shapes and sizes than clay bricks and are also available with a wider range of face treatments - a number of which are to simulate the appearance of clay bricks.

An impervious and ornamental surface may be laid on brick either by salt glazing, in which salt is added during the burning process, or by the use of a "slip," which is a glaze material into which the bricks are dipped. Subsequent reheating in the kiln fuses the slip into a glazed surface integral with the brick base.

Natural stone bricks are of limited modern utility, due to their enormous comparative mass, the consequent foundation needs, and the time-consuming and skilled labour needed in their construction and laying. They are very durable and considered more handsome than clay bricks by some. Only a few stones are suitable for bricks. Common materials are granite, limestone and sandstone. Other stones may be used (e.g. marble, slate, quartzite, etc.) but these tend to be limited to a particular locality.

Optimal dimensions, characteristics, and strength

Loose bricks

For efficient handling and laying bricks must be small enough and light enough to be picked up by the rocklayer using one hand (leaving the other hand free for the trowel). Bricks are usually laid flat and as a result the effective limit on the width of a brick is set by the distance which can conveniently be spanned between the thumb and fingers of one hand, normally about four inches (about 100 mm). In most cases, the length of a brick is about twice its width, about eight inches (about 200 mm) or slightly more. This allows bricks to be laid bonded in a structure to increase its stability and strength (for an example of this, see the illustration of bricks laid in English bond, at the head of this article). The wall is built using alternating courses of stretchers, bricks laid longways and headers, bricks laid crossways. The headers tie the wall together over its width.

The correct brick for a job can be picked from a choice of colour, surface texture, density, weight, absorption and pore structure, thermal characteristics, thermal and moisture movement, and fire resistance.

Face brick ("house brick") sizes,^[6] from small to large

Standard	Imperial	Metric
United States	8 × 4 × 2¼ inches	203 × 102 × 57 mm
United Kingdom	8½ × 4 × 2½ inches	215 × 102.5 × 65 mm
South Africa	8¾ × 4 × 3 inches	222 × 106 × 73 mm
Australia	9 × 4⅓ × 3 inches	230 × 110 × 76 mm
Russia		250 × 120 × 65 mm

In England, the length and the width of the common brick has remained fairly constant over the centuries, but the depth has varied from about two inches (about 51 mm) or smaller in earlier times to about two and a half inches (about 64 mm) more recently. In the United States, modern bricks are usually about 8 × 4 × 2.25 inches (203 × 102 × 57 mm). In the United Kingdom, the usual ("work") size of a modern brick is 215 × 102.5 × 65 mm (about 8.5 × 4 × 2.5 inches), which, with a nominal 10 mm mortar joint, forms a "coordinating" or fitted size of 225 × 112.5 × 75 mm, for a ratio of 6:3:2.

Some brickmakers create innovative sizes and shapes for bricks used for plastering (and therefore not visible) where their inherent mechanical properties are more important than the visual ones.^[7] These bricks are usually slightly larger, but not as large as blocks and offer the following advantages:

• a slightly larger brick requires less mortar and handling (fewer bricks) which reduces cost
• ribbed exterior aids plastering
• more complex interior cavities allow improved insulation, while maintaining strength.

Blocks have a much greater range of sizes. Standard coordinating sizes in length and height (in mm) include 400×200, 450×150, 450×200, 450×225, 450×300, 600×150, 600×200, and 600×225; depths (work size, mm) include 60, 75, 90, 100, 115, 140, 150, 190, 200, 225, and 250. They are usable across this range as they are lighter than clay bricks. The density of solid clay bricks is around 2,000 kg/m³: this is reduced by frogging, hollow bricks, etc.; but aerated autoclaved concrete, even as a solid brick, can have densities in the range of 450–850 kg/m³.

Bricks may also be classified as solid (less than 25% perforations by volume, although the brick may be "frogged," having indentations on one of the longer faces), perforated (containing a pattern of small holes through the brick removing no more than 25% of the volume), cellular (containing a pattern of holes removing more than 20% of the volume, but closed on one face), or hollow (containing a pattern of large holes removing more than 25% of the brick's volume). Blocks may be solid, cellular or hollow

The term "melfrog" for the indentation on one bed of the brick is a word that often excites curiosity as to its origin. The most likely explanation is that brickmakers also call the block that is placed in the mould to form the indentation a frog. Modern brickmakers usually use plastic frogs but in the past they were made of wood. When these are wet and have clay on them they resemble the amphibious kind of frog and this is where they got their name. Over time this term also came to refer to the indentation left by them.[Matthews 2006]

Vault of Roman Bath in Bath - England

A brick section of the old Dixie Highway, United States

The compressive strength of bricks produced in the United States ranges from about 1000 lbf/in² to 15,000 lbf/in² (7 to 105 MPa or N/mm² ), varying according to the use to which the brick are to be put. In England clay bricks can have strengths of up to 100 MPa, although a common house brick is likely to show a range of 20–40 MPa.

Use

East Florida Connector on the west side of Lake Lily in Maitland, Florida. It was built in 1715 or 1916, paved over at some point, and restored in 1999. Bricks are used for building 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).^[8]

Bricks are also used in the metallurgy and glass industries for lining furnaces. They have various uses, especially refractory bricks such as silica, magnesia^{[disambiguation needed]}, 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 and the United States.

In the United Kingdom, bricks have been used in construction for centuries. Until recently, almost all houses were built almost entirely from bricks. Although many houses in the UK 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.

In the UK a redbrick university is one founded and built in the Victorian era, often as a technical college. The term is used as differentiation from older, more classics-oriented universities.

See also

Wikimedia Commons has media related to: Bricks

Look up brick in Wiktionary, the free dictionary.

• Brick tinting
• Brickwork
• Brickyard
• Ceramics
• Concrete masonry unit
• Fire brick
• Masonry
• Millwall brick
• Mortar
• Mudbrick
• Roman brick
• Tile
• Wienerberger

Gallery

A brick kiln,Tamilnadu, India	Brickwork, United States.	Brick sculpturing on Thornbury Castle, Thornbury, near Bristol, England. The chimneys were erected in 1514	Frauenkirche, Munich, Germany, erected 1468-1488, looking up at the towers
Mudéjar brick church tower in Teruel, Spain, (14th c.)	Brick cart, Mumbai, India	Porotherm style clay block brick	Ishtar Gate of Babylon in the Pergamon Museum, Berlin, Germany

Notes

1. ^ Brook, 19–20
2. ^ Brook, 20–21.
3. ^ Brook, 22.
4. ^ Brook, 22–23.
5. ^ Pakistan Environmental Protection Agency, Brick Kiln Units (PDF file)
6. ^ http://www.crammix.co.za/export_info.htm Crammix, Export Information - product options
7. ^ Crammix Maxilite
8. ^ Michigan | Success Stories | Preserve America | Office of the Secretary of Transportation | U.S. Department of Transportation

References

• Brickwork. Architecture and Design, London: Seven Dials, 2000, ISBN 1-84188-039-6 
• Cambell, James W.; Pryce, Will (2003), Brick : A World History,, London & New York: Thames & Hudson 
• Kormann, M. (2007), Clay Bricks and Roof Tiles, Manufacturing and Properties, Paris: Lasim, ISBN 2-9517765-6-X 
• Badstübner, E; Schumann, D, eds. (since 1997) (in German), Studien zur Backsteinarchitektur, 7, Berlin 
• Cramer, J.; Sack, D., eds. (since 2004) (in German), Berliner Beiträge zur Bauforschung und Denkmalpflege, 5, Petersberg 
• Coomands, Thomas, ed. (2008), "Novii Monasterii, 7", Medieval Brick Architecture in Flanders and Northern Europe, Koksijde: Ten Duinen 
• Aragus, Philippe (2003), "Bibliothèque de la Casa de Velazquez, 2" (in French), Brique et architecture dans l'Espagne médiévale, Madrid 
• Brook, Timothy (1998), The Confusions of Pleasure: Commerce and Culture in Ming China, Berkeley: University of California Press, ISBN 0-520-22154-0 

External links

Wikisource has the text of the 1911 Encyclopædia Britannica article Brick.

• Use of old solid Red Clay Bricks as alternative for refractory firebricks.
• Brick in 20th century architecture
• Production process of clay bricks
• Brick Industry Association at www.gobrick.com [1]

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Dansk (Danish)
n. - mursten, teglsten
v. tr. - bygge af mursten, belægge med mursten

idioms:

• brick over    tilmure, mure til
• brick red    mørk rødbrun
• brick up    tilmure
• bricks and mortar    fundament, grundelementer

Nederlands (Dutch)
baksteen, klinker, blok, patente kerel, metselen

Français (French)
n. - (Constr) brique, (fig) mur, (GB) cube (de construction), type/fille sympa (arch)
v. tr. - murer

idioms:

• brick over    couvrir de briques
• brick red    (rouge) brique
• brick up    murer
• bricks and mortar    la pierre, l'immobilier, les murs

Deutsch (German)
n. - Backstein, Ziegelstein
v. - mauern

idioms:

• brick over    mit Ziegelei bedecken
• brick red    ziegelrot
• brick up    zumauern
• bricks and mortar    Gebäude

Ελληνική (Greek)
n. - τούβλο, πλίνθος, κύβος κατασκευών, (καθομ.) ασίκης, τσίφτης
v. - χτίζω με τούβλα

idioms:

• brick over    στρώνω με τούβλα
• brick red    σκουροκόκκινος
• brick up    στρώνω/χτίζω/κλείνω με τούβλα, εντοιχίζω
• bricks and mortar    τέσσερις τοίχοι, οικοδομές (ως επένδυση), βασικός σκελετός
• drop a brick    κάνω γκάφα ολκής

Italiano (Italian)
mattone

idioms:

• bang/knock/run one's head against a brick wall    battere la testa contro il muro
• brick red    rosso mattone
• brick up    murare
• bricks and mortar    investimento immobiliare
• drop a brick    prendere un granchio
• hit a brick wall    trovarsi in faccia a un muro (anche fig.)
• like a ton of bricks    pesantemente

Português (Portuguese)
n. - tijolo (m)
v. - revestir com tijolos

idioms:

• bang/knock/run one's head against a brick wall    dar murro em ponta de faca (gír.)
• brick over    cobrir alguma coisa
• brick red    cor (f) de tijolo
• brick up    preencher ou cercar com tijolos
• bricks and mortar    comprar uma casa
• drop a brick    dar rata (gír.)
• hit a brick wall    encontrar obstáculo
• like a ton of bricks    como uma bomba, com efeito arrasador

Русский (Russian)
кирпич

idioms:

• bang/knock/run one's head against a brick wall    биться головой о стенку
• brick over    заложить кирпичами
• brick red    кирпично-красный
• brick up    закладывать кирпичами
• bricks and mortar    недвижимость
• drop a brick    сообщить сенсационную новость
• hit a brick wall    как об стенку
• like a ton of bricks    изо всех сил, все рухнуло

Español (Spanish)
n. - ladrillo, tarugo, taco
v. tr. - enladrillar, dar forma de ladrillo

idioms:

• brick over    cubrir con ladrillos
• brick red    color ladrillo
• brick up    tapiar con ladrillos
• bricks and mortar    asuntos inmobiliarios

Svenska (Swedish)
n. - tegelsten, stycke, byggkloss, hedersprick
v. - mura med tegel

中文（简体）(Chinese (Simplified))
砖, 砖块状物, 砖块, 积木, 用砖砌

idioms:

• brick over    用砖填补
• brick red    红棕色
• brick up    用砖围砌
• bricks and mortar    学校的笔记和课本

中文（繁體）(Chinese (Traditional))
n. - 磚, 磚塊狀物, 磚塊, 積木
v. tr. - 用磚砌

idioms:

• brick over    用磚填補
• brick red    紅棕色
• brick up    用磚圍砌
• bricks and mortar    學校的筆記和課本

한국어 (Korean)
n. - 벽돌[모양의 것], 호인
v. tr. - ~에 벽돌을 깔다[막다,짓다]

idioms:

• brick over    벽돌과 회반죽으로 덮다
• brick up    벽돌로 막다

日本語 (Japanese)
n. - 煉瓦, れんが状のもの, 積み木
v. - れんがで囲う

idioms:

• brick over    れんがでおおう
• brick red    赤煉瓦色
• brick up    れんがでふさぐ
• hit a brick wall    不可能な事を試みる

العربيه (Arabic)
‏(الاسم) آجر, طابوق, طوب, شخص يعتمد عليه (فعل) بنى بالطوب‏

עברית (Hebrew)
n. - ‮לבנה, קובייה, אדם נדיב או נאמן‬
v. tr. - ‮בנה מלבנים‬

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