Concrete is a major material used in the construction industry that emits a large amount of substances with environmental impacts during its life cycle. Accordingly, technologies for the reduction in and assessment of the environmental impact of concrete from the perspective of a life cycle assessment (LCA) must be developed. At present, the studies on LCA in relation to greenhouse gas emission from concrete are being carried out globally as a countermeasure against climate change. However, the studies on the impact of the substances emitted in the concrete production process on acidification and eutrophication are insufficient. As such, assessing only a single category of environmental impact may cause a misunderstanding about the environmental friendliness of concrete. The substances emitted in the concrete production process have an impact not only on global warming but also on acidification and eutrophication. Acidification and eutrophication are the main causes of air pollution, forest destruction, red tide phenomena, and deterioration of reinforced concrete structures. For this reason, the main substances among those emitted in the concrete production process that have an impact on acidification and eutrophication were deduced. In addition, an LCA technique through which to determine the major emissions from concrete was proposed and a case analysis was carried out. The substances among those emitted in the concrete production process that are related to eutrophication were deduced to be NO_x, NH₃, NH₄⁺, COD, NO₃⁻, and PO₄³⁻. The substances among those emitted in the concrete production process that are related to acidification, were found to be NO_x, SO₂, H₂S, and H₂SO₄. The materials and energy sources among those input into the concrete production process, which have the biggest impact on acidification and eutrophication, were found to be coarse aggregate and fine aggregate.

As the greenhouse gas reduction goal of 37% below business-as-usual (BAU) by 2030, the construction industry is recognized as an anti-environment industry for mass consumption/mass waste; thus, members of the industry are requested to make efforts to transform it into an environment-friendly industry. Concrete, a common construction material, is known to emit large amounts of environmentally hazardous waste during the processes related to its production, construction, maintenance, and demolition. The amount of greenhouse gas (GHG) emissions by the product is specified in a ready-mixed concrete report whenever concrete is sold commercially. Hence, there have been many studies addressing the quantitative evaluation and reduction of the environmental effects of concrete. This study aims to introduce a method for assessing the amount of carbon dioxide emission from the processes of producing concrete. Moreover, we measured the quantities of CO₂ emission of about 10 under-construction projects, including office buildings, apartment buildings, and high-rise residential buildings in South Korea. Using the assessment result, we analyzed the CO₂ reduction performance of an office building in South Korea and drew conclusions about measures for reducing CO₂ emission.

This study assessed the influence of matter discharged during the production (dry/wet) of recycled aggregate on global warming potential (GWP) and acidification potential (AP), eutrophication potential (EP), ozone depletion potential (ODP), biotic resource depletion potential (ADP), photochemical ozone creation potential (POCP) using the ISO 14044 (LCA) standard. The LCIA of dry recycled aggregate was 2.94 × 10⁻² kg-CO_2eq/kg, 2.93 × 10⁻⁵ kg-SO_2eq/kg, 5.44 × 10⁻⁶ kg-PO₄³_eq/kg, 4.70 × 10⁻¹⁰ kg-CFC_11eq/kg, 1.25 × 10⁻⁵ kg-C₂H_4eq/kg, and 1.60 × 10⁻⁵ kg-Antimony_eq/kg, respectively. The environmental impact of recycled aggregate (wet) was up to 16~40% higher compared with recycled aggregate (dry); the amount of energy used by impact crushers while producing wet recycled aggregate was the main cause for this result. The environmental impact of using recycled aggregate was found to be up to twice as high as that of using natural aggregate, largely due to the greater simplicity of production of natural aggregate requiring less energy. However, ADP was approximately 20 times higher in the use of natural aggregate because doing so depletes natural resources, whereas recycled aggregate is recycled from existing construction waste. Among the life cycle impacts assessment of recycled aggregate, GWP was lower than for artificial light-weight aggregate but greater than for slag aggregate.

Concrete is a type of construction material in which cement, aggregate, and admixture materials are mixed. When cement is produced, large amounts of substances that impact the environment are emitted during limestone extraction and clinker manufacturing. Additionally, the extraction of natural aggregate causes soil erosion and ecosystem destruction. Furthermore, in the process of transporting raw materials such as cement and aggregate to a concrete production company, and producing concrete in a batch plant, substances with an environmental impact are emitted into the air and water system due to energy use. Considering the fact that the process of producing concrete causes various environmental impacts, an assessment of various environmental impact categories is needed. This study used a life cycle assessment (LCA) to evaluate the environmental impacts of concrete in terms of its global warming potential, acidification potential, eutrophication potential, ozone depletion potential, photochemical ozone creation potential, and abiotic depletion potential (GWP, AP, EP, ODP, POCP, ADP). The tendency was that the higher the strength of concrete, the higher the GWP, POCP, and ADP indices became, whereas the AP and EP indices became slightly lower. As the admixture mixing ratio of concrete increased, the GWP, AP, ODP, ADP, and POCP decreased, but EP index showed a tendency to increase slightly. Moreover, as the recycled aggregate mixing ratio of concrete increased, the AP, EP, ODP, and ADP decreased, while GWP and POCP increased. The GWP and POCP per unit compressed strength (1 MPa) of high strength concrete were found to be about 13% lower than that for its normal strength concrete counterpart. Furthermore, in the case of AP, EP, ODP, and ADP per unit compressed strength (1 MPa), high-strength concrete was found to be about 10%~25% lower than its normal strength counterpart. Among all the environmental impact categories, ordinary cement was found to have the greatest impact on GWP, POCP, and ADP, while aggregate had the most impact on AP, EP, and ODP.

This study aims to develop a system for assessing the impact of the substances discharged from concrete production process on six environmental impact categories, i.e., global warming (GWP), acidification (AP), eutrophication (EP), abiotic depletion (ADP), ozone depletion (ODP), and photochemical oxidant creation (POCP), using the life a cycle assessment (LCA) method. To achieve this, this study proposed an LCA method specifically applicable to the Korean concrete industry by adapting the ISO standards to suit the Korean situations. The proposed LCA method involves a system that performs environmental impact assessment on the basis of input information on concrete mix design, transport distance, and energy consumption in a batch plant. The Concrete Lifecycle Assessment System (CLAS) thus developed provides user-friendly support for environmental impact assessment with specialized database for concrete mix materials and energy sources. In the case analysis using the CLAS, among the substances discharged from the production of 24 MPa concrete, those contributing to GWP, AP, EP, ADP, ODP, and POCP were assessed to amount to 309 kg-CO₂ eq/m³, 28.7 kg-SO₂ eq/m³, 5.21 kg-PO₄³⁻ eq/m³, 0.000049 kg-CFC₁₁ eq/m³, 34 kg/m³, and 21 kg-Ethylene eq/m³, respectively. Of these six environmental impact categories selected for the LCA in this study, ordinary Portland cement (OPC) was found to contribute most intensely to GWP and POCP, and aggregates, to AP, EP, ODP, and ADP. It was also found that the mix design with increased prop proportion of recycled aggregate was found to contribute to reducing the impact in all other categories.

To comply with recent international trends and initiatives, and in order to help achieve sustainable development, Korea has established a greenhouse gas (GHG) emission reduction target of 37% (851 million tons) of the business as usual (BAU) rate by 2030. Regarding environmentally-oriented standards such as the IGCC (International Green Construction Code), there are also rising demands for the assessment on CO₂ emissions during the life cycle in accordance with ISO (International Standardization Organization’s Standard) 14040. At present, precast concrete (PC) engineering-related studies primarily cover structural and construction aspects, including improvement of structural performance in the joint, introduction of pre-stressed concrete and development of half PC. In the manufacture of PC, steam curing is mostly used for the early-strength development of concrete. In steam curing, a large amount of CO₂ is produced, causing an environmental problem. Therefore, this study proposes a method to assess CO₂ emissions (including absorption) throughout the PC life cycle by using a life cycle assessment (LCA) method. Using the proposed assessment method, CO₂ emissions during the life cycle of a precast concrete girder (PCG) were assessed. In addition, CO₂ absorption was assessed against a PCG using conventional carbonation and CO₂ absorption-related models. As a result, the CO₂ emissions throughout the life cycle of the PCG were 1365.6 (kg-CO₂/1 PCG). The CO₂ emissions during the production of raw materials among the CO₂ emissions throughout the life cycle of the PCG were 1390 (kg-CO₂/1 PCG), accounting for a high portion to total CO₂ emissions (nearly 90%). In contrast, the transportation and manufacture stages were 1% and 10%, respectively, having little effect on total CO₂ emissions. Among the use of the PCG, CO₂ absorption was mostly decided by the CO₂ diffusion coefficient and the amount of CO₂ absorption by cement paste. The CO₂ absorption by carbonation throughout the service life of the PC was about 11% of the total CO₂ emissions, which is about 16% of CO₂ emissions from ordinary Portland cement (OPC) concrete.