Life Cycle Analysis for Brick
Life Cycle Analysis For Brick 1Materials are very important in construction industry because with the combination of different material, we can create a very strong and unique building form. There are many type of material that commonly used in the construction industry, for example the glass, woods, bricks, stones, marble, concretes and etc. Brick is one of the most commonly used materials in Malaysia, because almost every house in housing area was built by bricks.
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From this essay I want to give analysis about the brick life cycle included its origin and how the brick being used after the end of its life cycle. 2Brick was appeared since the beginning of the civilization, which is the ancient Mesopotamia around 8000 BC. (Think Brick Australia 2007) The thick clay and mud leave by the Tigris and Euphrates Rivers was reinforced with straw and shaped into brick and then dried in the sun.
Bricks were glazed in a variety of colours as the time progressed and used to decorate the facades of the ziggurat, or temple towers, built as stairways to and for the Gods. In the end, people started to realize that when the wooden houses burned and the brick on the remaining chimneys had been strengthened, so fire-hardened bricks began to replace adobe ones in India and the Middle East. And the Romans used kiln-burned brick in conjunction with an efficient mortar of lime and volcanic ash to construct buildings that were both beautiful and last longer. Think Brick Australia 2007) 3Brick is a masonry unit of clay, formed into a rectangular prism while plastic and hardened by firing in a kiln. The manufacture of bricks is used easily workable and clayey materials and the materials are avoided to contain any large hard components or lumps of lime, this is to avoid crack and split of the brick. We can obtain clay on the surface of the ground. There are three principal form of clay used to manufactured clay brick which are surface clay, shales, and fire clays.
The surface clays is sedimentary clays which found near the surface of the earth, shales is clay that have been subjected to high pressures until they have hardened almost to the form of slate, and the fire clays is clays which have found deeper in the ground than other types and to have refractory qualities. These three principal forms of clays have similar chemical compositions but appear in different physical. The clays can easily be found and to extract because usually we can find it in the ground surface. After the clay has been extract from the ground, it covered with water, usually used to be work by hand with special hoe.
There are several processes to form a brick which are soft mud process, stiff mud process and dry-press process. (Ching and Adams 2001, 12. 06) The soft mud process refers to forming brick by molding relatively wet clay having a moisture content of 20 percent to 30 percent. (Ching and Adams 2001, 12. 06) The Stiff mud process refers to forming brick and structural tile by extruding stiff but plastic clay having moisture content of 12 percent to 15 percent and then the de-airing machine will removes air and eliminating holes and bubbles in the clay. Ching and Adams 2001, 12. 06) After that the clay is force through die and cutting the extrusion to length with wires before to heat the finish in the kiln. The dry-press process refers to forming brick by molding relatively dry or low plasticity clay which having moisture content of 5 percent to 7 percent under high pressure, the resulting of this process is sharp-edged, smooth-surfaced bricks. (Ching and Adams 2001, 12. 06) 4The most important step to form a stronger brick is through the drying and firing process.
There are three different kinds generally used the humidity system of drying can be applied to any type of dryer, as the term humidity drying represents a process rather than a form of structural design. Humidity drying may be divided into three stages: first is the heating stage, during which the clay is gradually heated up in an atmosphere of relatively high humidity, this prevents excessive cracking or distorting on the face of the brick. After that is the drying period, in which the air is heated to a maximum temperature for the clay being dried, the humidity is gradually decreased to allow the clay to dry uniformly all the way through.
And the third which is the cooling stage, in which the temperature is gradually decreased to uniformity. The clay is not fully dried when placed in the kiln. Hygroscopic water is not driven off at ordinary temperatures or even at the boiling point of water. In fact, the temperature often rises quite a bit above the boiling point before the water is completely evolved. The watersmoking is accomplished by fire in the kiln furnaces. Wood is frequently used for this purpose, to avoid sooting. In the watersmoking eriod it is desired to heat up the brick, evaporate and remove the moisture, and to accomplish this successfully, it is very necessary that draft be strong. The watersmoking is the most critical point in the life of the brick. The process must be carried very slowly the water in coming out of the clay may crack the surface. After the watersmoking is completed, the temperature is increase to that required in oxidation. Oxidation begins in the later stages of vitrification, but the greater part occurs between the temperatures of 800oF and 1300oF.
At this stage most of the impurities are given off and the metals constituting the clay are changed to their respective oxides. The highest temperature reached at this point is usually near 2000oF. 5Brick grade designates the durability of a brick unit when exposed to weathering. The United States is divided into three weathering regions, severe, moderate, and negligible, according to annual winter rainfall and the annual number of freezing-cycle days. (Ching and Adams 2001, 12. 6) Brick is graded for use in each region according to compressive strength, maximum water absorption, and maximum saturation coefficient. The three grades are SW is brick suitable for exposure to severe weathering, as when in contact with the ground or used on surfaces likely to be permeated with water in subfreezing temperatures; minimum compressive strength of 17238 kPa. (Ching and Adams 2001, 12. 06) MW is brick suitable for exposure to moderate weathering, as when used above grade on surfaces unlikely to be permeated with water in subfreezing temperatures; minimum compressive strength of 15169 kPa. Ching and Adams 2001, 12. 06) NW is brick suitable for exposure to negligible weathering, as when used as a backup or interior masonry; minimum compressive strength of 18243 kPa. (Ching and Adams 2001, 12. 06) 6The manual production of the bricks involves mainly four operations namely, soil preparation, moulding, drying and firing. The main process in which energy is consumed is firing of bricks. The amount of total coal required is about 18 tonnes to 22 tonnes depending upon the weather condition, quality of coal, etc.
A tonne of coal gives about 12. 3MJ to 13. 3MJ depending upon the quality of the coal generally transported from far off distances. (Gumaste n. d. ) The energy required to produce each brick inclusive of transportation comes to about 5 MJ per brick. (Gumaste n. d. ) Advantage of using bricks One of the advantages of using brick to build building is because brick is a high thermal mass material, it absorb heat throughout the day and release it slowly at night, this is ensuring internal temperatures are consistent throughout the day and night.
The result is we’re able to have comfortable and healthy living and working environment in which to enjoy stable temperatures throughout the year. Brick building also very sustainable because they highly durable, offer long term life performance, low maintenance, and energy efficient and recyclable. But bricks have been labeled as having high embodied energy due to their process of manufacture. However, in measuring sustainability it is necessary to take into account a material’s life cycle performance, s well as the amount of energy consumed in the manufacturing process.
And a recent research by think brick demonstrates that the proportion of embodied energy of clay bricks for the modern semi-detached home is equal to just 1. 87 percent of the over all heating requirement for the home over its 150 year life. Moreover during the manufacture of brick, very little clay is wasted, and those unfired waste clay is reused in the manufacturing process and less than perfect fired bricks are crushed and used as a aggregates in other parts of the building industry. In conclusion, brick has a very high embodied energy during manufacture, especially in the firing system which required many of the energy to burn the brick, but it is highly durable, offer long term life performance and low maintenance so it is very suitable as a material to built the long stay building. Reference list: Berge, B and Trans. 2000. The Ecology of Building Materials. London: Reed Educational and Professional Publishing Ltd. Ching, F. D. K. , and C. Adams. 2001. Building construction illustrated. 3rd ed. Toronto: John Wiley & sons Inc. Gumaste, K. S. n. d.
Embodied energy computations in buildings. http://www. ese. iitb. ac. in/aer2006_files/papers/144. pdf (accessed September 24, 2008) Simmons, H. L. 2001. Construction Principles Materials and Methods. 7th edition. New York: John Willey and Sons Inc. Think Brick Australia. 2007. Why choose Brick? Sustainability. http://www. thinkbrick. com. au/thinking-brick/why-brick/sustainability_home/sustainability_home. cfm (accessed October 10, 2008). Think Brick United Kingdom. 2007. Why Brick? http://www. brick. org. uk/about-us/why-use-brick. html (accessed on September 24, 2008)