# Proposal for the Evaluation of Eco-Efficient Concrete
## 3 Proposed Assessment Method for the Eco-Efficiency of Concrete
### Eco-Efficiency Assessment Method of Concrete  
#### 3.4.1 Environmental Performance (EP)  
For the assessment of concrete eco-efficiency, environmental performance was assessed using a lifecycle assessment (LCA) technique. 1. Definition of purpose and scope  
General concrete was selected as the product subject to LCA, and the formation of concrete structure and concrete product was selected as the primary function of concrete. The functional unit was defined as 1 m\({}^{3}\) of concrete based on the primary function. 2. Life Cycle Impact Assessment (LCIA)  
Life Cycle Impact Assessment (LCIA) is a process that assesses the potential effects of indicators (input and output) created during lifecycle impact analysis on the environment. Concrete is a mixture of cement, aggregates, and admixtures. Large amounts of energy are consumed during the collection of limestone or clay and the manufacture of clinker. Soil erosion or destruction of the ecosystem may occur from the collection of aggregates. In addition, because energy is also used during the transport of materials such as cement and aggregate to concrete manufacturers and during the production of concrete, diverse substances that incur environmental loads on air, water systems, and soil are emitted. Because different environmental impacts occur during the lifecycle of concrete, multiple environmental impact assessments must be conducted on various aspects from production to use and disposal of functional units of concrete. Indeed, the assessment of a single environmental impact, such as global warming, fails to comprehensively assess the environmental performance of concrete (Figure 5). Accordingly, Life Cycle Impact Assessment (LCIA) on concrete was conducted based on standard substances and impact indicators for each of the six environmental impact categories, global warming, resource consumption, acidification, eutrophication, effects on the ozone layer, and creation of photochemical oxides [17]. Figure 5: Environmental impacts that occur during the product lifecycle of concrete. Life Cycle Impact Assessment (LCIA) is divided into four steps: (1) classification in which the inventory items extracted from the inventory analysis are assigned to the corresponding impact categories; (2) characterization in which the impact of each item classified into its impact category on each category is quantified; (3) normalization in which the environmental impact exerted on the environmental categories are divided into local or global environmental impacts; and (4) weighting in which relative importance among the impact categories is determined. According to ISO 14044 [18], the classification and characterization steps are mandatory assessment steps, and the normalization and weighting steps may be optionally assessed depending on the assessment purpose. In this study, assessment was performed for the classification and characterization steps because factors for concrete-related normalization and weighting suitable for Korean situations are yet to be developed. The standard substances and impact potentials for environmental impact categories were applied in accordance with the respective databases used in the Ministry of Environment for the eco-labeling of the Environmental Declaration of Products [19; 20]. The classification and characterization steps of assessment were performed on the basis of the previously selected LCI (Life Cycle Inventory) database [21]. Classification is done by categorizing and compiling the inventory items according to the environmental impact categories. By linking the inventory items derived from the LCI database to the pertinent environmental impact categories and integrating them by category, the environmental impact of each inventory item can be clearly identified. CO\({}_{2}\), CH\({}_{4}\), and N\({}_{2}\)O belong to the 23 GHGs specified in the Intergovernmental Panel on Climate Change (IPCC) guidelines [22], of which the standard substance is CO\({}_{2}\).