Concrete's Increasing Unsustainability - Literature review Example

CONCRETE Introduction Concrete is according to Cement concrete and Aggregates Australia (2010) the most used material in the world today. As a composite material, concrete is a combination of coarse granular material also known as aggregate and cement binder treated to the required hardness. Concrete material shot up to popularity due to discovery of its durability and adjustable strength that could fit the economic value, utility versatility and its universal acceptability. Further to this statement, concrete is believed to be a sustainable building material in as much as the competitors to this material believe that greener materials such as bamboo and timber. This report thus seeks to give a clear picture of sustainability levels that concrete possesses as compared top timber and bamboo when it comes to construction. Comparative Sustainability of Concrete In their conference proceedings article “Is Concrete Sustainable?” Struble & Godfrey (2007), cite that the manufacturing process involved in coming up with a construction material contributes a lot to its sustainability. This includes the energy expenditure and the concoction of raw materials that are utilized in this process. When coming up with the environmental impact for sustainability survey for any material, it is therefore essential that the raw materials be checked for recyclability, renewability, scarcity, importance to the global environment and impact of waste to the environment. The construction process and the expenditures involved are also worth consideration coupled by the durability and adaptability of the resulting structure. According to Naik (2008), human development requires sustainable building products for continued wellbeing and growth of the larger society. The main constituents of concrete i.e. aggregate and Portland cement have led to eruption of debates from time to time. It has been established that the production of Portland cement is one of the leading sources of carbon dioxide and other greenhouse gases. According to Global Cement (2013) in the last decade alone, more than 25 cement plants have been closed down due to allegations of this nature. Further to these facts, the natural resources that are required for production of cement have continued to dwindle over time. Good quality limestone that is used for production of high grade cement for example has continued to become rare even as the global appetite for complex projects is on a steady increase. Sustainability dictates that the structures that are built through whichever methodology be environmental friend throughout the existence cycle. The methodology itself should not be marred by extinction due to lack of support materials as in the case of concrete which has taken a negative turn as seen in various geographical regions which have turned for more greener materials due to diminishing resources. Concrete sustainability is further described by Chao (2008) as the ability of the manufacturer to use minimal energy resources during production followed by a low probability of introducing environmental waste. This article can authoritatively report that concrete is a major resource hog based on the above argument. Concrete on the other hand possesses high thermal mass, produces durable buildings, requires low maintenance and can be recycled at will by contractors. This mix of advantages and disadvantages has led to green evolution in the cement sector in a bid to offset the growing demand of green products. Concrete has been established as one of the materials that are most desirable due to its superior energy performance, dependability, durability, affordability and design flexibility (Struble & Godfrey, 2007). These advantages are obtained by combining small amounts of steel reinforcements where necessary. The revolution in the concrete building material sector has also seen the emanation of pre-stressed concrete which is usually precast for site application. The production of this material however involves other procedures such as early hydration and removal of form work to render it useful. This leads to reduced environmental impact due to landfill exposure and low energy usage by site workers. Lifetime sustainability of concrete includes the energy transmittance capability and the energy storage. As much as concrete is a good insulator, it does not offer good retaining properties due to the inclusion of steel rebar and sections for strengthening purposes. The insulation capability of concrete in comparison to timber is very low thus the competitive edge that timber possesses against the former. This is brought about by high porosity which gives a high thermal mass as compared to timber. The disposure of concrete at the end of structural cycle involves brute force and controlled blasting in order to come up with small pieces that can be conveniently loaded. The materials that come out of this venture can be used as landfill and pavement sub base (Struble & Godfrey, 2007). In a bid to advance the sustainability of concrete, concrete and cement industries are encouraged to adopt sustainable technologies that are supposed to reduce the emissions. According to Naik (2008), there are many treaties that have been set in place to curb the emission of green house gases to the atmosphere by the cement manufacturers. The most important of these treaties is the Kyoto Protocol (UNFCCC COP9 Rep.2004) that stated that brought manufacturers from the world together in a bid to reduce the levels of greenhouse gases that have become an environmental menace. An approximated 28 billion tonnes of greenhouse gases have been implicated on the cement and concrete industry prompting the green movement to sway away from utilizing the materials associated with cement. The green movement has advocated on the usage of timber and bamboo from time and again owing to the facts enlisted above. Timber is considered as sustainable in areas that require truly recyclable building materials. Some countries have ensured sustainability of forests meant for timber production by enacting re-growing policies once felling is carried out. The extraction process of timber is on the other hand easier and cheaper compared to concrete. An analysis of the insulation properties of timber as a construction material shows that it outperforms concrete by a ratio of 1:400. The energy needed for purposes of heating and cooling is thus reduced to a significant level that is labelled as sustainable. This also applies to the use of bamboo for such purposes as flooring and also walling material (Stommel Haus Agency, 2013). Carbon sequestration is achieved as a result of the replanted trees and bamboos within the production areas that are exploited for the purpose of production continuation. In order to achieve a usable amount of timber, construction companies are usually prompted to develop large tracts of land into forests. Through photosynthesis (a plant process that transforms solar energy, water and carbon dioxide into food and oxygen as a by-product) a large amount of carbon dioxide is used thus mitigating the green house gases effects. Another explanation given by builders is that good quality timber achieves high insulation thereby reducing the need for home owners to run their air conditioning systems. Considering that wood retains 2°C of temperature as compared to concrete, then the amount of carbon dioxide that can be eliminated from the atmospheric system by 1m3 is one tone (Lorenz & Lal, 2010). Other sustainable properties of timber emanate from the fact that it provides a healthy environment through its ability to diffuse gas and hygroscopic nature. Timber regulates humidity within the building and regulates the smell of the air for maintenance of human senses. Furthermore, timber consists of endless design possibilities that can be easily approached by the technical team. Considering this statement, timber structures are quickly realized thereby offering sustainability with respect to time and low budget which translates to financial sustainability. Due to biodegradability and recyclability of timber, the waste that is released to the environment is very minimal (Keeping & Shiers, 2004). Rapid bamboo growth and development is seen as the main sustainable property that is possessed by this building material. Conventional forests take a greater time to grow as compared to bamboo. In a bid to make this material more sustainable, the scientists have discovered the thinning process through which this grass is made healthier thereby offering it a chance to regenerate faster than normal. This plant is also environmental friendly and is hailed for its ability to eliminate green house gases and carbon dioxide from the environment with ease (although lower than trees). This material is financially sustainable in that it does not require any enhancers during its growth period and the harvesting is cheaper as compared to trees. Utilization of this material within a regulated environment that is governed by replanting immediately after the harvesting process is not disputed by any environmental activism agency. Deforestation on the other hand has been disputed throughout the world whether on bamboo or tree plantations since this act renders the atmosphere unsustainable (Bamboo Fencer, 2009). Conclusion Concrete is quickly becoming unsustainable due to the depletion of natural resources that are associated to production of its main ingredient. The associated pollution of the environment through the introduction of greenhouse gases and damage of natural habitats including the earth topography is alarming thus considerations should be made for utilization of alternative/ green materials that are deemed as sustainable both environmentally or economically. On the other hand, the suggested materials i.e. timber and bamboo are important for the carbon sequestration process in their raw form thus making use of them in an unregulated environment is unsustainable. References Bamboo Fencer. (2009). Bamboo and Sustainability. Retrieved January 11, 2013, from Bamboo Fencer: http://www.bamboofencer.com/About-Bamboo/Bamboo- Sustainability Chao, S.-H. (2008). Achieving “Green” Concrete Through he Use Of High Performance Fiber Reinforced Concrete. Presentation at ASCE Texas Section Fall Meeting (pp. 1-29). Texas: The University of Texas Arlington. Global Cement. (2013 , August 21). Displaying items by tag: Closure. Retrieved January 07, 2014, from Global Cement: http://www.globalcement.com/news/itemlist/tag/Closure Keeping, M., & Shiers, D. (2004). Sustainable Property Development: A Guide to Real Estate and the Environment. Oxford: John Wiley & Sons. Lorenz, K., & Lal, R. (2010). Carbon Sequestration in Forest Ecosystems. London: Springer. Naik, T. R. (2008). Sustainability of Concrete Construction. Practice Periodical on Structural Design and Construction , 98–103. Stommel Haus Agency. (2013). 6 good Reasons to Build a Contemporary Timber House. Retrieved January 7, 2014, from Stommel Haus: http://www.stommel- haus.co.uk/home/goodreasons Struble, L., & Godfrey, J. (2007). How Sustainable is Concrete? Proceedings of the International Workshop on Sustainable Development and Concrete Technology, Beijing, China, May 20-21, 2004, (pp. 201-211). Iowa. Read More