Composite construction is a generic term to describe any building construction involving multiple dissimilar materials. Composite construction is often used in building

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

watercraft A watercraft or waterborne vessel is any vehicle designed for travel across or through water bodies, such as a boat, ship, hovercraft, submersible or submarine. Types Historically, watercraft have been divided into two main categories. *Raf ...

, and

building construction Construction are processes involved in delivering buildings, infrastructure, industrial facilities, and associated activities through to the end of their life. It typically starts with planning, financing, and design that continues until the a ...

. There are several reasons to use

composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...

s including increased strength,

aesthetics Aesthetics (also spelled esthetics) is the branch of philosophy concerned with the nature of beauty and taste (sociology), taste, which in a broad sense incorporates the philosophy of art.Slater, B. H.Aesthetics ''Internet Encyclopedia of Ph ...

, and environmental

sustainability Sustainability is a social goal for people to co-exist on Earth over a long period of time. Definitions of this term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions (or pillars): env ...

Structural engineering

structural engineering Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and joints' that create the form and shape of human-made Structure#Load-bearing, structures. Structural engineers also ...

, composite construction exists when two different materials are bound together so strongly that they act together as a single unit from a

structural A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

point of view. When this occurs, it is called composite action. One common example involves

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

beams supporting

concrete 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-manufactur ...

floor slabs. If the beam is not connected firmly to the slab, then the slab transfers all of its weight to the beam and the slab contributes nothing to the load carrying capability of the beam. However, if the slab is connected positively to the beam with studs, then a portion of the slab can be assumed to act compositely with the beam. In effect, this composite creates a larger and stronger beam than would be provided by the steel beam alone. The structural engineer may calculate a transformed section as one step in analyzing the load carry capability of the composite beam.

Ships

In 19th-century shipbuilding, composite construction was the use of an iron hull framework which was covered in timber planking to provide the water-tight skin of the hull. If properly insulated fastenings were used on the timber, the underwater hull could be covered with

copper sheathing Copper sheathing is a method for protecting the hull of a wooden vessel from attack by shipworm, barnacles and other marine growth through the use of copper plates affixed to the surface of the hull, below the waterline. It was pioneered and d ...

without the problem of

galvanic corrosion Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, different metal, when both in the prese ...

. Copper sheathing prevented

fouling Fouling is the accumulation of unwanted material on solid surfaces. The fouling materials can consist of either living organisms (biofouling, organic) or a non-living substance (inorganic). Fouling is usually distinguished from other surfac ...

and teredo worm, but could not be used on iron hulls. The iron framework of composite ships was less bulky and lighter than timber, so allowing more cargo in a hull of the same external shape. The weight saving was particularly significant. The strength and stiffness allowed sailing vessels to be driven hard as the accumulated straining of the hull did not produce the leaks that would develop in the older wooden built ships. Composite hulls were used for the majority of the

clipper A clipper was a type of mid-19th-century merchant sailing vessel, designed for speed. The term was also retrospectively applied to the Baltimore clipper, which originated in the late 18th century. Clippers were generally narrow for their len ...

s built from the mid-1860s. Early experiments with the system started with a patent issued in 1839, under which the steamer ''Assam'' was built. Other patents followed, with differing methods of electrically insulating the iron frames and fastenings from the copper sheathing. Surviving examples are , a steam and sail-powered warship, and the clipper .

House building

A flitch beam is a simple form of composite construction sometimes used in North American light frame construction. This occurs when a steel plate is sandwiched between two wood joists and bolted together. A flitch beam can typically support heavier loads over a longer span than an all-wood beam of the same cross section.

Deck construction

Composite wood decking

The traditional decking material is pressure-treated wood. The current material many contractors choose to use is composite decking. This material is typically made from wood–plastic composite or fiberglass reinforced plastic (FRP). Such materials do not warp, crack, or split and are as versatile as traditional pressure treated wood. Composite decking is made through several different processes, and there are a multitude of sizes, shapes, and strengths available. Depending on the type of composite selected the decking materials can be used for a number of other construction projects including fences and sheds.

Composite steel deck

In a composite steel deck, the dissimilar materials in question are steel and concrete. A composite steel deck combines the tensile strength of steel with the compressive strength of concrete to improve design efficiency and reduce the material necessary to cover a given area. Additionally, composite steel decks supported by composite steel joists can span greater distances between supporting elements and have reduced live load deflection in comparison to previous construction methods.

Cement-polymer composites

Cement-polymer composites are being developed and tested as a replacement for traditional cement. The traditional cement used as stucco rapidly deteriorates. The deterioration causes the material to easily crack due to thermo-processes becoming permeable to water and no longer structurally sound. The

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent agency of the United States government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on De ...

in conjunction with Materials and Electrochemical Research Corporation tested a cement-polymer composite material consisting of

crumb rubber Crumb rubber is recycled rubber produced from automotive and truck scrap tires. During the recycling process, steel and tire cord (fluff) are removed, leaving tire rubber with a granular consistency. Continued processing with a granulator or ...

made from

recycled Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on its ability to reacquire the propert ...

rubber tires and

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...

. It was found that 20% crumb rubber can be added to the cement mixture without affecting the appearance of the cement. This new material was tested for strength and durability using American Society for Testing and Materials (

ASTM International ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...

) standards.Loutfy, R. O. (2005, April 25). National Center For Environmental Research, US EPA. Retrieved June 14, 2010, from Final Report: Cement-Polymer Composites From Recycled Polymers for Construction: http://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/6970/report/F

References

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