Composite material in the context of "Refractory"

Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. Being a natural material, it is characterized as an organic material – a natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin and hemicelluloses that resists compression.

Wood is sometimes defined as only the secondary xylem in the stems of trees, or more broadly to include the same type of tissue elsewhere, such as in the roots of trees or shrubs. In a living tree, it performs a mechanical-support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients among the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, woodchips, or fibers.

Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world.

When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical properties of the wet mix, delay or accelerate the curing time, or otherwise modify the finished material. Most structural concrete is poured with reinforcing materials (such as steel rebar) embedded to provide tensile strength, yielding reinforced concrete.

Papier-mâché (UK: /ˌpæpieɪ ˈmæʃeɪ/ PAP-ee-ay MASH-ay, US: /ˌpeɪpər məˈʃeɪ/ PAY-pər mə-SHAY, French: [papje mɑʃe] – the French term "mâché" here means "crushed and ground") is a versatile craft technique with roots in ancient China, in which waste paper is shredded and mixed with water and a binder to produce a pulp ideal for modelling or moulding, which dries to a hard surface and allows the creation of light, strong and inexpensive objects of any shape, even very complicated ones. There are various recipes, including those using cardboard and some mineral elements such as chalk or clay (carton-pierre, a building material). Papier-mâché reinforced with textiles or boiled cardboard (carton bouilli) can be used for durable, sturdy objects. There is even carton-cuir (cardboard and leather) and also a "laminating process", a method in which strips of paper are glued together in layers. Binding agents include glue, starch or wallpaper paste. "Carton-paille" or strawboard was already described in a book in 1881. Pasteboard is made of whole sheets of paper glued together, or layers of paper pulp pressed together. Millboard is a type of strong pasteboard that contains old rope and other coarse materials in addition to paper.

This composite material can be used in a variety of traditional and ceremonial activities, as well as in arts and crafts, for example to make many different inexpensive items such as Christmas decorations (including nativity figures), toys or masks, or models for educational purposes, or even pieces of furniture, and is ideal for large-scale production; Carton-pierre can be used to make decorative architectural elements, sculptures and statues, or theatre or film sets; papier-mâché has also been used to make household objects, which can become valuable if artistically painted (as many boxes and snuffboxes were in the past) or lacquered, sometimes with inlays of mother-of-pearl, for example. Large papier-mâché pieces, such as statues or carnival floats, require a wooden (or bamboo, etc.) frame. Making papier-mâché is also a popular pastime, especially with children.

Natural fibers or natural fibres (see spelling differences) are fibers that are produced by geological processes, or from the bodies of plants or animals. They can be used as a component of composite materials, where the orientation of fibers impacts the properties. Natural fibers can also be matted into sheets to make paper or felt.

The earliest evidence of humans using fibers is the discovery of wool and dyed flax fibers found in a prehistoric cave in the Republic of Georgia that date back to 36,000 BP. Natural fibers can be used for high-tech applications, such as composite parts for automobiles and medical supplies. Compared to composites reinforced with glass fibers, composites with natural fibers have advantages such as lower density, better thermal insulation, and reduced skin irritation. Further, unlike glass fibers, natural fibers can be broken down by bacteria once they are no longer used.

• A ″ natural material a substance that comes from plants, animals, or the earth, and has not been made by humans.. Minerals and the metals that can be extracted from them (without further modification) are also considered to belong into this category. Natural materials are used as building materials and clothing. Types include:

• Biotic materials
  • Wood (rattan, bamboo, bark, etc.)
• Plant fiber (coir, ramie, sisal, cotton, flax, hemp, jute, kapok, kenaf, moss, linen, abacá, etc.)
• Animal fiber (wool, silk, alpaca, camel, angora, cashmere, mohair, etc.)
• Inorganic material
  • Stone (flint, granite, limestone, obsidian, sandstone, sand, gems, glass, etc.)
  • Native metal (copper, iron, gold, silver, etc.)
  • Composites (clay, plasticine, etc.)
• Other natural materials.
  • Soil

Construction aggregate, or simply aggregate, is a broad category of coarse to medium-grained particulate material used in construction. Traditionally, it includes natural materials such as sand, gravel, and crushed stone. As with other types of aggregates, it is a component of composite materials, particularly concrete and asphalt.Aggregates are the most mined materials in the world, being a significant part of the 6 billion tons of concrete produced per year.

Aggregate serves as reinforcement to add strength to the resulting material. Due to the relatively high hydraulic conductivity as compared to most soil types, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under building foundations, roads and railroads (aggregate base). It has predictable, uniform properties, preventing differential settling under the road or building.

Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel reinforcing bars (known as rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.

Microstructure is the very small-scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material (e.g. metals, polymers, ceramics, or composites) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.

Microstructure at scales smaller than can be viewed with optical microscopes is often called nanostructure, while the structure in which individual atoms are arranged is known as crystal structure. The nanostructure of biological specimens is referred to as ultrastructure.