The process and practices of Sustainable Concrete Construction
In order to resolve global emission issues, sustainable concrete construction that involves green and eco-friendly concrete construction practices is very much required.
Concrete is a globally recognized construction material. Lots of concrete are formed and utilized in the globe and provide a great impact. All these contribute a significant part to the ecological issues of the globe.
The impact of concrete is happening in various phases ranging from taking out of the raw material till the end of structure life. Global warming is happening because of emission of CO2. It enhances landfill sizes, and pollutions. All these occur due to the impact of concrete.
To cope up with increased population density, the demand for concrete is also raised. It has also made the situation worst. So, immediate step is to opt for sustainable concrete construction practices.
Life Cycle Assessment of Concrete: Life cycle assessment is initiated for understanding and evaluating the concrete environmental impacts in a superior manner. It is essential to acquire all the life phases of concrete to evaluate the ecological impacts.
1. Concrete Manufacture: Cement, aggregate and water are the prime elements of concrete. Each of them contains raw materials with energy consumption and waste production.
Therefore, the manufacturing is treated as the most vital phase from ecological point of view.
By mixing limestone with clay sufficiently, cement is formed. The produced mixture is heated in a rotary kiln about 1450C. At this temperature chemical transformation happens and the basic material is transformed to clinker. Once cooling is completed, it ground in a rolling mill to form cement powder. All through this processes, energy is exhausted intensely with the discharge of CO2.
Limestone is primarily calcium carbonate CaCO3 and it is obtained through mining, by heating CaCO3 that decompose and discharge emission due to both clinker production and combustion of fossil fuel to produce energy necessary for the production process.
Aggregate and sand are responsible for approximately 30% of all CO2 emission during concrete production. The average concrete utilization is 1 tonne/ year/ single person, and 1 tonne CO2 is released/1tone produced cement which is 7% of global emission.
2. Concrete Construction: In this phase, fewer amount of greenhouse emission is discharged with regards to manufacturing. Batching of concrete is one of the disturbing factors.
The components of concrete are blended in a high placed container through electric power. Besides, little amount of fuel is discharged by small trucks to transmit virgin materials; 0.0033t CO2-e/m3 emission is discharged because of batching/m2.
To transmit the concrete, diesel fuel is applied that discharges 0.009t CO2-e/m3 along with empty returned journey.
Some activities like pumping, vibrating, and finishing which are accomplished in the construction site can discharge up to 1.5 L/m3pumped concrete). Often concrete is craned rather than pumped, therefore, (2×1.5 L/m3) to take other type of pumping into consideration and it discharges 0.009t CO2-e/m3.
Electric mixing produces highest amount of CO2 emission in this phase. As huge amount of concrete is utilized all through the world and most of projects employ ready mix plant, large amount of water is exhausted for washing machinery and curing concrete to bring the necessary strength in severe conditions, consequently huge amount of polluted water is produced; pure water is utilized to resist chemical reactions.
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