Life Cycle Analysis of Concrete in India

Why life cycle analysis of concrete is needed

life cycle analysis of concrete
Life cycle analysis of concrete is needed because construction is one of the largest contributors to greenhouse gases (GHG). Increasing development also adds to the risk of global warming.

What is the life cycle approach?

Life Cycle Approach is a method for assessing an activity by paying attention to each chain of a product. This helps us to select the most problematic and most influential points in a series of product cycles.

Some constructions use concrete because it has many variations for each purpose. Starting from the dam, the pier, to the future home for yourself with him.

However, although concrete has many benefits, the material itself also has a risk of global warming that comes from energy consumption, raw material extraction, land conversion, waste production, and the production of greenhouse gases itself.

The main ingredient of concrete is cement. By life cycle analysis of concrete, we can found that Cement has additives that have the potential to pollute the environment. Therefore, many researchers are trying to reduce cement consumption. To improve the engineering properties of concrete, researchers used fly ash, plastic powder, bagasse etc.

The manufacture of cement consumes high energy. This produces CO2 into the atmosphere and has the potential to cause global warming. To reduce this environmental impact, many researchers have tried to modify sustainable cement materials use the life cycle analysis of concrete

There are three types of cement that are often used, namely portland cement (OPC), ground granulated blast furnace slag (GGBS) and portland pozzolana cement (PPC). In order to find out which material is the best, a mixture is made like the following

  • Conventional concrete (100% OPC),
  • Mix-1 (100% PPC),
  • Mix-2 (50% GGBS and 50% OPC)
  • Mix-3 (100% GGBS)

The environmental impact of the cement material will be calculated using the life cycle analysis of concrete

What processes need to be calculated for the environmental impact?

The LCA study conducted by Manjunatha et.al. This starts from the raw material being extracted until it becomes a cement product. The process under review includes

• Raw Material Extraction

• Transportation

• Manufacture

• Manufacturing waste treatment

How do you conduct a life cycle analysis? 

From all these processes we can conduct an LCA study in the following steps. The main stages of the LCA are regulated according to ISO 14040 and 14044. 

  1. Goal and scope definition
  2. Inventory analysis
  3. Impact assessment
  4. Interpretation

These procedures can be executed sequentially. However, during the course of your study life cycle analysis of concrete, you may revise the previous steps. So overhauling the steps of the LCA is reasonable for the improvement of future studies.

From the life cycle analysis of concrete, the environmental impact is calculated for every kilogram of cement produced. From this, it can be seen which mixture of materials has the least environmental impact. The environmental impact to be studied is

  • include climate (Global Warming)
  • human toxicity,
  • loss of the ozone layer,
  • acidification,

The result

LCA studies for concrete have been done before. This can be seen from the ecoinvent database also loading concrete. The difference between this study and the LCA database in ecoinvent is that the alternative mixtures of aggregates in concrete are alternative.

What is the composition of each mixture from this research conducted by Manjunatha et.al?

  • Cement 15.84%
  • Aggregate 46.71% = 1162 kg
  • Sand 29.72% = 737 kg
  • Water 7.6% = 190 kg

Furthermore, the cement is modified again according to the mixture that has been previously mentioned on life cycle analysis of concrete

  • Conventional concrete (OPC 394 kg),
  • Mix-1 (PPC 394 kg),
  • Mix-2 (GGBS 197 kg and OPC 197kg)
  • Mix-3 (GGBS 394 kg)

How different are the environmental impacts of life cycle analysis of concrete?

The impact of global warming

  • Conventional concrete = 9.63%
  • Mix-1 (100% PPC), = 6.92%
  • Mix-2 (50% GGBS and 50% OPC) = 5.02%
  • Mix-3 (100% GGBS) = 1.33%

Ozone depletion

  • Conventional concrete = 4.63%
  • Mix-1 (100% PPC), = 3.02%
  • Mix-2 (50% GGBS and 50% OPC) = 2.12%
  • Mix-3 (100% GGBS) = 1.33%

Human toxicity, which is the cause of cancer in humans

  • Conventional concrete = 3.02%
  • Mix-1 (100% PPC), = 2.22%
  • Mix-2 (50% GGBS and 50% OPC) = 1.49%
  • mix-3 (100% GGBS) = 1.33% = 0%

Terrestrial acidification is also caused because the cement manufacturing process produces SO2, NH3 and NHx.

  • Conventional concrete
  • Mix-1 (100% PPC)
  • Mix-2 (50% GGBS and 50% OPC)
  • Mix-3 (100% GGBS) = 0.157%

From all the life cycle analysis of concrete studied, it can be seen that PPC and GGBS provide less impact than OPC. However, in the future PPC and GGBS will be used for high temperature buildings so that they will also increase emissions from fossil fuel combustion.

However, this study of life cycle analysis of concrete only compares the raw materials extracted to cement. So the environmental impact at use is not taken into account.

Also see: Life Cycle Assessment Environmental Impact of Gold

Source: Manjunatha et.al. 2021. Life cycle assessment (LCA) of concrete prepared with sustainable cement-based materials 

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