Examining The Quality Standards Of Construction Materials Construction Essay

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Materials used within the construction industry in the U.K are specified by a quality standard, which can be a British Standard (BS) or a British / European Standard (BS EN). Materials need to be used in the context of the design and therefore need to meet a certain criteria. For example, the material used for windows must be glass therefore; it is 'fit for purpose' and necessary for the specific design criteria.

The arc furnace process starts off by using cold materials. A vessel is charged with scrap steel (which contains a lot of recycled materials), then the vessel lid is closed and the electric probes are dropped inside. The power is then switched on and an electric arc is formed, which produces heat. The mixture is melted and then other metals are added as and when required to produce steel of the highest quality. Oxygen is then blown into the vessel to purify the steel. The secondary process forms the steel again into the final product.

The basic oxygen converter process uses molten iron which has been produced in a blast furnace (as in the diagram below). Then the molten iron is poured into a vessel alongside some scrap steel and a lance is used to blow pure oxygen through the mixture. This removes any impurities which float to the top and are removed by scraping them from the top layer. The pure steel is then taken to be processed into billets, blooms or slabs or it can go through a secondary process and rolled into shape. This whole process may take less than an hour to complete. Steel is used to construct bridges, buildings and is a very important commodity within the construction and civil engineering industry.

Brickwork / Block work - Bricks have been manufactured for thousands of years from as far back as Egyptians building mud brick pyramids to the present day. In the U.K, clay is the principle ingredient of the brick and this is excavated and transported to a process plant, also known as a brick works. The clay is then processed in order for it to be moulded or cut to shape which allows for specific sizes of bricks to be produced. The bricks are then dried in open air and stacked ready for firing in a kiln. The firing process is very important as this hardens the brick and provides strength and durability. There are many different applications which may be used in order to produce a specific type of brick. Upon completion of the firing process the bricks are then stacked into packs and wrapped ready for transportation. Bricks and blocks are used to build buildings, retaining walls and many other structures. The bricks are placed on a bed of mortar which is a cement based adhesive and placed strategically against one another, in order to maximise the strength and load bearing capabilities of the structure.

Timber - Timber is classified into two categories: softwoods and hardwoods. It should be noted the term Hardwoods and Softwoods should not be misinterpreted as an indicator of their strength. Softwoods are coniferous or cone bearing trees and have needle-like leaves and are mostly evergreen, they are usually found in the Northern Hemisphere. Hardwoods are usually found in the Southern Hemisphere and are produced from broad-leaved trees which produce seeds contained in an enclosed case, such as Acorns or Walnuts. Timber has been used in the construction industry for many years, timber is forested from sustainable forests where the selected mature trees are cut down and processed within a saw mill. A process know as kiln drying is carried out in order to remove the moisture from the timber, this process also increases the strength of the timber greatly. TRADA (The Timber Research and Development Association) illustrates various timber grades and their uses. It also provides information regarding typical spans in which timber may be used for. After the moisture content drops below 20% various timber products can be produced. Timber is used in the construction industry in many ways such as; constructing roofs and floors, wall cladding, and internal second fix within buildings such as door frames, skirting boards, back moulds and many more. Timber is also used during concrete pours (shuttering) and 'setting out' by engineers.

Brickwork and block work - During construction brickwork and blockwork are bind together with cement mortar. The mortar sets and holds the bricks and blocks in place. If the mortar is not mixed to the correct ratio, there is a potential for failure due to the strength of the binding material not being correct. Brickwork and blockwork are relatively strong on compression but can be pushed over laterally and due to this fact they need to be 'tied in' during the construction project. Brickwork is very durable if constructed correctly and the face of the brick is of good quality. A well maintained mortar bed is also imperative in order to prevent excessive water ingress. Frost attack can also occur to brickwork and blockwork which causes cracks to the material and parts of the material break off the structure. This is due to the frost expanding under the material and forcing failure. To prevent such failure, less porous or newer bricks should be used in areas where frost is a known factor. Efflorescence is also a known factor which can cause the material to fail. Water migrates through the brickwork and blockwork dissolving salt minerals contained within the material. The salt crystals then dry out on the surface of the brickwork and form a white area which is not pleasing on the eye. In order to prevent efflorescence occurring, great care should be taken in selecting the sand used for the mortar within the structure. Efflorescence will eventually be washed out of a structure and treatment can be added to protect the structure.

It is very important preventative techniques are undertaken prior to the construction phase of a project. Planners should be looking at what material is best suited for average weather conditions, geological conditions for the specific area and the overall perception of the project. It is more cost effective to spend a little more money on preventative measures as oppose to having to dismantle a roof due to insect attack or demolish a building due to stress fractures within the steel structure or concrete foundations. Material which are used within the construction and civil engineering industry have to be fit for purpose and must be visually appealing. Materials also need to fall within certain cost parameters in order for budgets and contracts to be drawn up. The specified materials should also have a certain resistance to degradation as this will prolong the lifespan of the overall project. Ease of installation is also very important as this will allow for the project to run as smooth as possible. When planners are selecting materials, consideration must be taken into account as to how much embedded energy is used in producing them as there is greater pressure for the world to be as environmentally friendly as possible. Materials used within the projects should also be sustainable and have recycling potential. It is very important for materials to be safe for use and be compatible with one another.