Analysis of Environmental Impact for Concrete Using LCA by Varying the Recycling Components, the Compressive Strength and the Admixture Material Mixing

Abstract

Abstract: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.

Development of the CO2 Emission Evaluation Tool for the Life Cycle Assessment of Concrete

“…The material reuse rate is a value in an index form obtained by analyzing the amount of raw material input and the recycled amount of the recovered material. The energy reduction rate is a value in an index form representing fuel consumption and renewable energy production in each process [27]. …”

Strength, Carbon Footprint and Cost Considerations of Mortar Blends with High Volume Ground Granulated Blast Furnace Slag

“…It is a systematic set of procedures developed to compile, examine, and evaluate the material and energy balance of the system by converting those inputs and outputs to associate with potential environmental impact that is directly attributable to the operation of a product or service system throughout its entire life cycle. LCA is one of the most effective and common methods used for evaluation and comparison of the environmental impact of different concrete mix design [18][19][20]. Hence, LCA can help in decision making of selecting suitable mix designs based on environmental performances.…”

Life Cycle Assessment of Palm Oil Clinker as a Binder and Aggregate Replacement in Concrete

“…Specifically, the GWP of which is expressed in the unit kilograms of carbon dioxide equivalent (kg CO 2 eq). The GWP for various normal concrete mixes in the literature and their corresponding compressive strength are shown in Table 9 (Marinkovic et al, 2010;Tosic et al, 2015;Kim, Tae, and Chae;2016;Tait and Cheung;2016, Braga, Silvestre andde Brito, 2017;Mohammadi and South 2017;Ahmad et al, 2017;Kurda, Silvestre and de Brito, 2018). The z-score was calculated for the GWP value of mix C-0 in this study (GWP = 436 kg CO 2 eq.)…”