A brick is a type of block used to build walls, pavements and other elements in masonry construction. Properly, the term brick denotes a block composed of dried clay, but is now also used informally to denote other chemically cured construction blocks. Bricks can be joined using mortar, adhesives or by interlocking them. Bricks are usually produced at brickworks in numerous classes, types, materials, and sizes which vary with region and time period, and are produced in bulk quantities.
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.
Fired bricks are one of the longest-lasting and strongest building materials, sometimes referred to as artificial stone, and have been used since circa 4000 BC. Air-dried bricks, also known as mud-bricks, have a history older than fired bricks, and have an additional ingredient of a mechanical binder such as straw.
According to Lukas Nickel, the use of ceramic pieces for protecting and decorating floors and walls dates back at various cultural sites to 3000-2000 BC and perhaps even before, but these elements should be rather qualified as tiles. For the longest time builders relied on wood, mud and rammed earth, while fired brick and mud-brick played no structural role in architecture. Proper brick construction, for erecting walls and vaults, finally emerges in the third century BC, when baked bricks of regular shape began to be employed for vaulting underground tombs. Hollow brick tomb chambers rose in popularity as builders were forced to adapt due to a lack of readily available wood or stone. The oldest extant brick building above ground is possibly Songyue Pagoda, dated to 523 AD.
By the end of the third century BCE in China, both hollow and small bricks were available for use in building walls and ceilings. Small fired bricks were first mass-produced during the construction of the tomb of China's first Emperor, Qin Shi Huangdi. The floors of the three pits of the terracotta army were paved with an estimated 230,000 small bricks, with the majority measuring 28x14x7 cm, following a 4:2:1 ratio. Up until the Middle Ages, buildings in Central Asia were typically built with unbaked bricks. It was only starting in the ninth century CE when buildings were entirely constructed using fired bricks.
Production of bricks increased massively with the onset of the Industrial Revolution and the rise in factory building in England. For reasons of speed and economy, bricks were increasingly preferred as building material to stone, even in areas where the stone was readily available. It was at this time in London that bright red brick was chosen for construction to make the buildings more visible in the heavy fog and to help prevent traffic accidents.
Following pioneering work in the 1950s at the Swiss Federal Institute of Technology and the Building Research Establishment in Watford, UK, the use of improved masonry for the construction of tall structures up to 18 storeys high was made viable. However, the use of brick has largely remained restricted to small to medium-sized buildings, as steel and concrete remain superior materials for high-rise construction.
Clay and shale are the raw ingredients in the recipe for a fired brick. They are the product of thousands of years of decomposition and erosion of rocks, such as pegmatite and granite, leading to a material that has properties of being highly chemically stable and inert. Within the clays and shales are the materials of aluminosilicate (pure clay), free silica (quartz), and decomposed rock.
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. 2b1af7f3a8