The use of Recycled concrete aggegates in construction Essay Example
- Category:Engineering and Construction
- Document type:Assignment
RЕСYСLЕD СОNСRЕTЕ АGGЕGАTЕS IN СОNSTRUСTIОN 7
The use of rесyсlеd соnсrеtе аggrеgаtеs in соnstruсtiоn
The use of rесyсlеd соnсrеtе аggrеgаtеs in соnstruсtiоn
With the need for sustainability, the aspect of recycling is extremely relevant. Individuals and organizations are expected to be conscious of the environment and engage in sustainable processes and procedures and one of them is recycling. Recycling entails the conversion of waste materials into new materials that could be used productively rather than throwing them away. It is one way of allowing for sustainability by avoiding waste of potentially valuable materials and minimizing the use of fresh raw materials. In a way, it reduces pollution and energy usage. This piece of work will give an in-depth discussing of the use of recycled concrete aggregates in construction and various aspects associated with it. Much emphasis will be placed on the significance of using reinforced concrete in construction and why it is better than steel and other construction materials.
When doing construction, there is the option of using natural aggregates and that of using recycled concrete aggregate. Each option has its pros and cons and the decision to use either is dictated by various factors. Recycling is a process that was conceived with an aim of conserving the environment and enhancing sustainability. This is more so because it prevents the use of new raw materials and instead make valuable use of what could otherwise be waste. The debate over what is better between concrete and steel has been on-going, some parties being in favour of either concrete or steel. According to Buildings (2005), concrete and steel have different characteristics and benefits and the decision to state which is better than the other depends on one’s view on the same. Some of the attributes through which the two materials can be compared and contrasted include; safety, cost, material availability, construction scheduling, design possibilities, and environmental considerations among others.
With regard to safety, recycled concrete is safer. When the core of a building is made of concrete, it offers protection especially in case of terrorist attack or fire. Reinforced concrete is in a position to give outstanding resistance to impact or explosion. It is also in a position to endure extremely high temperatures from fire. For this reason, it does not need additional fireproofing measures to meet stringent fire standards and withstand natural and manmade calamities. It can also resist heavy winds. With proper design, concrete-built buildings also exhibit increased ductility, an aspect that is desirable in locations that are prone to seismic activity. On the other hand, steel is also strong but exposure to extremely high temperatures can make it soften and melt. It therefore requires additions for it to be safe and withstand high fire temperatures (Buildings, 2005). Safety is a major issue of concern especially when it comes to buildings since the lack of it could be fatal especially when disasters strike.
Cost is an issue of concern when it comes to building materials. Reinforced concrete is relatively cost effective compared to steel. Even with the rising prices of construction materials, the cost of concrete has been relatively stable. The return on investment achieved is attractive compared to the high price that could be associated with initial cast-in-place concrete construction. Recycling of concrete aggregates could also make the reinforced concrete cheaper since it entails the use of materials that would otherwise go to waste. The price of steel has gone up considerably. With regard to their availability, both concrete and steel have experienced some shortage over the past (Alengaram, Salam, Jumaat, Jaafar & Saad, 2011). Nonetheless, they are still being used and recycling of concrete aggregates makes the situation even better.
Construction scheduling is also a significant factor of comparison between concrete and steel. According to Buildings (2005), building with concrete is faster than with structural steel. Concrete can also be designed into many different shapes and the buildings made of it provide some real space advantages. Steel is also flexible. Sustainability and environment consideration is another issue of concern especially at this era where people are more aware of their rights and the need to uphold sustainability. Concrete is usually sourced locally and hence, it needs minimal energy when it comes to transportation to building sites. Recycled steel is also used in producing rebar for concrete and the used concrete can also be crushed and recycled. On the other hand, recycling is also done on steel. There is however high energy in terms of transportation since the fabrication is done at a considerable distance from a building site.
The above comparison and contrast between concrete and steel shows that both materials are essential and commonly used in the construction industry. Both have considerable benefits based on their physical characteristics and other external factors. Concrete seems to outweigh steel and it is therefore a better option. Nonetheless, this is not to say that steel has lost relevance since some still prefer it to concrete. Aspects such as engineering and proper design are in a position to make any of the construction material better.
After the comparison of steel and concrete, it is worth examining concrete in a more detailed manner with regard to why it is more commonly used, the characteristics as well as benefits involved. Oikonomou (2005) asserts that concrete is the most commonly used construction material in the world. When concrete is examined over its life cycle, it makes a considerable contribution to the triple line of sustainable development; social, economic and environmental development. The cycle entails extraction, processing, construction, operation, demolition and recycling, all of which are relatively sustainable compared to other construction materials. It is also a versatile construction material. Although it is plastic and supple when newly mixed, it is durable, strong and hardened. This is enough reason as to why it is used in the construction of bridges, highways, dams, bridges, and houses.
Concrete has been identified as one of the construction materials that allows for the reduction of carbon dioxide emissions as well as other negative environmental effects in various sectors. For instance, buildings that are built of concrete have been found to last longer, minimize energy use and maintenance as well as offer better indoor air quality. Concrete highways also have some advantages. They necessitate less maintenance and they minimize fuel consumption by trucks that are heavily loaded. With regard to agricultural waste containment, the use of concrete minimizes odour and at the same time prevent the contamination of groundwater (Alengaram, Salam, Jumaat, Jaafar & Saad, 2011). All these are positive aspects when it comes to sustainability and hence the increased popularity of the use of concrete for various purposes.
Amidst the benefits and positive attributes of concrete, it also has some limitations. For instance, it has low ductability, it is vulnerable to cracking, it has relatively low tensile strength compared other construction material and low strength-to-weight ratio. All in all, these does not in any way make concrete less popular in construction. Some of these limitations can be reduced with proper engineering and designs. For example, there are various ways through which concrete may be reinforced to make it better as a construction material. Steel rebar could be used since it is excellent in tension and poor in compression. Chicken wire is also used to minimize thermal expansion (Oikonomou, 2005). Also, the benefits of using concrete outweigh these limitations by far. Being long lasting, economical, having optimal energy performance and being safe and sustainable are some of the positive attributes that overshadow the above named limitations.
The use of concrete in construction in Victoria and Melbourne in a particular is worth noting in this discussion. Here, commercial and high rise construction depends heavily on the utilization of reinforced concrete especially for structural components. Since late 19th century, there has been an increase in the use or concrete in construction not only in Victoria but Australia at large. Today, there are many cement companies that serve all states in Australia with cements of various categories. To show how important concrete is in the construction industry in Australia, there are many bodies that exist in this area as a way of regulating and managing it to get maximum benefits. One of them is the Cement Concrete &Aggregates Australia (CCAA). This is a peak body that is in charge of the heavy construction materials industry in the nation. It is a body of those who operate hard rock quarries, concrete batching plants, cement manufacturing and distribution facilities. This indicates that concrete is a great element of the construction industry in Australia. Some of the famous buildings that have been built using concrete include; Box Hill Hospital and My80 among others (Form700, 2013).
From the above discussion, it is apparent that the use of recycled concrete aggregate in the construction industry has continued to gain considerable popularity. The advantages associated with it and the fact that it allows for sustainability is one of the reasons that has seen it being utilized even in famous buildings. Despite the fact that steel and other materials are still used in construction, recycled concrete aggregate is likely to overshadow their use in the near future. This is more so because of the benefits associated with it as discussed above.
Alengaram, U. J., Salam, A., Jumaat, M. Z., Jaafar, F. F., & Saad, H. B. (2011). Properties of high-workability concrete with recycled concrete aggregate. Materials Research, 14(2), 248-255.
Buildings (2005). Concrete Vs Steel. Retrieved from http://www.buildings.com/article-details/articleid/2511/title/concrete-vs-steel/viewall/true
Form700 (2013). Current Projects. Retrieved from http://www.form700.com.au/current-projects/
Oikonomou, N. D. (2005). Recycled concrete aggregates. Cement and concrete composites, 27(2), 315-318.
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