Construction materials: Stone and Ceramics

Stone materials are often used for construction because they are strong, durable and very resistant to weather conditions. Stone is extracted from natural deposits called quarrying. The stone blocks are processed by cutting, shaping and polishing them. Some aggregates are used during the process for cleaning, crushing and sorting the stone blocks.
piedras
Gustavo Belemmi (Dominio público)

Marble, granite and slate are materials found in nature as large blocks of rocks, but we can also find them in different sizes and fragments for example sand and gravel.

Characteristics of some natural stones

  • Marble: It's a metamorphic rock, hard, dense and resistant to compression and enviromental conditions. It's cold to the touch and it has  a widely varied naturals colours. It's used on floors and walls, in architecture and in sculpture.
  • Granite: It's an igneous rock (quartz, feldspar and mica) – very resistant to impacts, compression and erosion. It's used in walls and floors.
  • Slate: It's a metamorphic rock, hard, dense, compact and waterproof. It's extracted from the quarrying in smooth, flat pieces that are cut and pressed. It's used to cover roofs and as paving stones.
  • Limestone: It's a sedimentary rock, porous, off-white. It's used in pavements.
  • Tuff: a light, porous rock formed by consolidation of volcanic ash. It's a black, porous and thermal insulator. It's used in masonry, in pavement, in windbreaks

Binders are used to bind or join other materials together. Sand and gravel are used as binders to make for example asphalt and cement, plaster, mortar and concrete are also considered binders. All binders need water for joining materials. When water is added, there is an exothermic chemical reaction that leads to a setting process.

Characteristics of some binders:

  • Plaster: It's obtained from gypsum rock that is crushed and dehydrated. Then it's mixed with water to make a paste that hardens rapidly. Properties: sticky, resistant to compression and fire. It's used to make archways, partitions, and as a covering for walls and paving.
  • Cement: grey powder make from a mixture of crushed and heated limestone, clay and gypsum. Properties: very hard and resistant. It's used to make mortar and others binders for construction materilas like bricks.
  • Mortar: It's a binder made from cement and sand, it hardens when mixed with water. It's used to hold together construction materials like bricks, cement blocks and paving stone, and it is also used for making artificial stone.
  • Concrete: It's a mixture of sand, gravel, water and cement that dries and hardens. Properties: very resistant to pressure, but not to traction. Reinforced concrete (with steel bars) then, it's also resistant to traction. It's used to make foundations for buildings, bridges, etc.

Concrete, hempcrete bricks, terrazo and fibre cement are binders that are also considered artificial stones. Fibre cement is a mixture of fibres covered with mortar that is waterproof and resistant. Hempcrete bricks are bricks made of a mixture of hemp fibre, soil and lime. They are thermal and acoustic insulators. Terrazzo is a mixture of gravel and white cement and it's a very resistant material.

Ceramic materials

They are made from clay. Clay is a fine-grained earth composed of aluminium silicates and other substances. When clay is wet, it is both soft and pliable, so it can be shaped very easily. Once clay dries, it becomes porous and chemically inert, as well as resistant to high temperatures. It has many different colours, it's abundant in nature and many versatile.

  • COARSE CERAMICS: they are water-permeable.

Terracotta: Ordinary clay that is usually a matte red colour. It is hard, rough and fragile. Uses: Bricks

Earthenware: A mixture of white clay, silica and feldspar. It is fine and smooth, as well as hard. Uses: Crockery, decoration and bathroom tiles

Refractory ceramics: Baked clay and metal oxides. They can resist temperatures up to 3 000ºC. Uses: Spacecraft, bricks, linings for industrial ovens, electrical components

  • FINE CERAMICS: They are non-permeable with certain glass-like properties.

Stoneware: It is made from refractory clay, has a glass-like appearance. It is very compactable and hard. Uses: Tiles, tubes and pipes and bricks

Porcelain: It is made with kaolin. It is transparent, translucent, compact, acid-resistant and hard. Uses: Industrial, food dishes and decoration 

  • GLASS: is a transparent or translucent material that can have different textures and colours. 

It is made with a mixture of sand, quartz, lime and soda, which is melted in a kiln at temperatures of more than 1 400ºC. It is hard and smooth, but also fragile. Glass is resistant to weather and chemical agents, as well as a good thermal, electrical and acoustic insulator.

Glass forming techniques: We make glass by mixing sand, soda and limestone. Look at the videos about different techniques of forming glass by clicking on its name

Hot glass is poured into a hollow mould; then compressed air is used to push the glass
The mould is opened and the glass object is taken out.

Hot glass is poured into a mould and allowed to cool.
It is used to make ashtrays, containers, bottles, glass bricks for construction

  • Drawing

Hot glass is drawn, or pulled, from a tank by using a machine that forms sheets.
It is used to make plate glass to make windows, windscreens and mirrors.

Hot glass is poured into a tank that contains liquid metal, such as tin.
Same applications as drawing.

Hot glass goes though a system of rollers.
It is used to make safety glass.

Ceramics in general are materials made from nonmetallic minerals that have been fired at high temperatures. These materials are used in spacecraft because they can withstand extreme temperatures and because they insulate well. These same qualities will probably prove useful in other vehicles.

Some new experimental engines include ceramic parts. Diesel engines used in trucks produce great amount of heat. In order to give trucks a more aero-efficient shape, the engine must be redesigned. Some engines makers are looking for ways to use ceramics to replace metal parts or to protect them from the heat. Then, air-cooling in trucks will not be necessary and their profiles can be changed and fuel efficiency should increase.

Composites

A composite is a new material made by combining two or more materials. Each component of a composite retains its own properties, but the resulting material has more desirable qualities. Composites are been used more and more today to make parts of the different types of transportation and structures.

Fiberglass reinforced with a resin is now being used for boat hulls and automobile bodies.

Kevlar is a composite very difficult to cut, it's being used to make reinforcing belts for tires.

Carbon composite and granite composite are now being used to make lightweight bicycle frames and to produce several new types of aircraft.

In summary, the use of composites in transportation systems and in structures will increase as different materials are combined and found to be lighter, safer and longer-lasting.

SPANISH TERMS

  • Quarry: cantera
  • Binder: aglutinante
  • Marble: marmol
  • Granite: granito
  • Limestone: caliza
  • Slate: Pizarra
  • Tuff: Toba
  • Plaster: Yeso (preparado)
  • Gypsum: Yeso (piedra)
  • Mortar: mortero
  • Concrete: hormigón
  • Clay: barro o arcilla
  • Coarse ceramic: Cerámica de construcción
  • Earthenware: Loza de barro
  • Feldspar: feldespato
  • Stoneware: gres
  • Lime: cal
  • Automatic blow moulding: moldeo por soplado automático
  • Glass Casting: fundición de vidrio
  • Calendering: calandrado
  • Crockery: Vajilla, loza
  • Piable: flexible
  • Melt: derretir
  • Spacecraft: Nave espacial
  • Withstand: soportar
  • Engine: motor
  • Retain: conservar
  • Fiberglass: fibra de vidrio
  • Boat hulls: Cascos de los barcos
  • Tires: neumáticos
  • Lightweight : ligero
  • Longer-lasting: duradero