Gyeonggi Do, South Korea
Gyeonggi Do, South Korea

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Kim H.,Building and Urban Research Institute | Park S.,Building and Urban Research Institute | Lee S.,Building and Urban Research Institute
Materials | Year: 2016

There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

Kim B.,Building and Urban Research Institute | Boyd A.J.,McGill University | Kim H.-S.,Building and Urban Research Institute | Lee S.-H.,Building and Urban Research Institute
Construction and Building Materials | Year: 2015

This research paper have evaluated the performance of durability of fibre-reinforced concrete through various test methods exposed to pH 4.5 solutions for 27 months with uncracked and precracked beams. The structural fibres used in this study were hooked end steel, polypropylene (PP) and polyvinyl alcohol (PVA) fibres and the strong acid solutions were simulated with acetic acid at the laboratory. The evaluation methods for durability performance subsequent to conditioning included ultrasonic pulse velocity (UPV), carbonation, residual strength and toughness. The additional tests such as absorption, permeability and diffusion for transport properties of harmful materials were performed. The experimental results showed significant reductions in both residual strength and toughness were found against low pH solutions, as well as the analysis of ultra-pulse velocity (UPV) and carbonation for all fibre mixtures. Consequently, in case of steel fibre-reinforced concrete indicating good resistance to the movement of harmful materials into concrete have excellent durability performance and then PVA, PP fibres in sequence. © 2015 Elsevier Ltd. All rights reserved.

This study developed and tested a home energy audit methodology that can be operated easily and quickly by novices in the field of building physics, mechanical systems, and building energy simulations such as homeowners. The home energy audit methodology was composed of three procedures as follows: an initial simulation procedure that can run the simulation easily, a calibration procedure that calibrates the initial simulation using a year of monthly utility bills, and a procedure to determine energy and cost efficient measures. In the previous study, the procedure for calibrating a residential simulation was developed, and in another study, the procedure was applied to an existing single-family house and energy and cost efficient measures were determined. In the previous studies, the procedures were validated in one case-study, single-family house in Texas, USA. In this paper, the overall procedure for the home energy audit methodology is presented and verified by two additional single-family houses in two different locations in Texas. In a similar fashion as the application to the first house, the most suitable retrofit measures for both of the new houses were determined according to their building and systems conditions, and corresponding cost savings. © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Kim T.H.,Building and Urban Research Institute | Chae C.U.,Building and Urban Research Institute
Sustainability (Switzerland) | Year: 2016

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 NOx, NH3, NH4 +, COD, NO3 -, and PO4 3-. The substances among those emitted in the concrete production process that are related to acidification, were found to be NOx, 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. © 2016 by the authors.

Cho S.-H.,Building and Urban Research Institute | Chae C.-U.,Building and Urban Research Institute
Sustainability (Switzerland) | Year: 2016

There have been much interest and many efforts to control global warming and reduce greenhouse gas (GHG) emissions throughout the world. Recently, the Republic of Korea has also increased its GHG reduction goal and searched for an implementation plan. In buildings, for example, there have been technology developments and deployment policies to reduce GHG emissions from a life cycle perspective, covering construction materials, building construction, use of buildings and waste disposal. In particular, Korea's Green Standard for Energy and Environmental Design is a certification of environmentally-friendly buildings for their energy saving and reduction of environmental pollution throughout their lives. In fact, the demand and adoption of the certification are rising every year. In construction materials and buildings, as a result, an environmentally-friendly aspect has become crucial. The importance of construction material and building development technologies that can reduce environmental load by diminishing GHG emissions in buildings has emerged. Moreover, there has been a rising necessity to verify the GHG reduction effects of buildings. To assess the reduction of carbon emissions in the buildings built with low-carbon construction technologies and materials, therefore, this study estimated life cycle carbon emissions in reference buildings in which general construction materials are used and in low-carbon buildings. For this, the carbon emissions and their reduction from construction materials (especially concrete) between conventional products and low-carbon materials were estimated, using Life Cycle Assessment (LCA). After estimating carbon emissions from a building life cycle perspective, their reduction in low-carbon buildings compared to the reference buildings was reviewed. The results found that compared to conventional buildings, low-carbon buildings revealed a 25% decrease in carbon emissions in terms of the reduction of Life Cycle CO2 (LCCO2) per unit area. If diverse production technologies and sales routes are further developed for low-carbon construction materials, carbon emission reduction effects would considerably increase. © 2016 by the authors.

Kim T.,Building and Urban Research Institute | Chae C.U.,Building and Urban Research Institute
Sustainability (Switzerland) | Year: 2016

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% (851million 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. © 2016 by the authors.

Jeong W.,University of Seoul | Kim K.H.,Building and Urban Research Institute
Sustainability (Switzerland) | Year: 2016

The development of separate building performance simulation tools has brought about a significant need for the integration of multi-domain simulations that would enable multiple building performance analyses to be conducted from a single building model. Insufficient data integration between the tools and Building Information Modeling (BIM) currently prevents the efficient production of comprehensive building performance analyses. To overcome this problem, a multi-domain simulation tool, effective and efficient data, and a process integration methodology are all required. Object-Oriented Physical Modeling (OOPM) has emerged as a form of object-oriented modeling capable of supporting multiple domain simulations. Adoption of OOPM into building performance simulations with BIM is particularly interesting as a means of facilitating model translations between BIM and BEM (Building Energy Modeling). Specifically, complex data translation from the building topology in BIM to the space boundary conditions in BEM is both labor intensive and time consuming. This research uses case studies to investigate the feasibility of automatically translating a building topology from BIM to OOPM-based BEM.We included numerous preconditions in order to incorporate various object semantic differences into each model translation. Our research indicates that this adoption approach allows seamless model translations from BIM to OOPM-based BEM, which supports efficient and effective thermal simulations and facilitates the reuse of BIM data in multi-domain simulations. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Kim H.,Building and Urban Research Institute | Park S.,Building and Urban Research Institute | Kim H.,Kongju National University
International Journal of Environmental Research and Public Health | Year: 2016

There has been increased deconstruction and demolition of reinforced concrete structures due to the aging of the structures and redevelopment of urban areas resulting in the generation of massive amounts of construction. The production volume of waste concrete is projected to increase rapidly over 100 million tons by 2020. However, due to the high cement paste content, recycled aggregates have low density and high absorption ratio. They are mostly used for land reclamation purposes with low added value instead of multiple approaches. This study was performed to determine an effective method to remove cement paste from recycled aggregates by using the abrasion and substituting the process water with acidic water. The aim of this study is to analyze the quality of the recycled fine aggregates produced by a complex method and investigate the optimum manufacturing conditions for recycled fine aggregates based on the design of experiment. The experimental parameters considered were water ratio, coarse aggregate ratio, and abrasion time and, as a result of the experiment, data concerning the properties of recycled sand were obtained. It was found that high-quality recycled fine aggregates can be obtained with 8.57 min of abrasion-crusher time and a recycled coarse aggregate ratio of over 1.5. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Kim T.H.,Building and Urban Research Institute
Sustainability (Switzerland) | Year: 2016

Studies which reduce cement usage, develop an alternative by partial replacement of cement with blast-furnace slag, fly ash, or such industrial byproducts, and evaluate the environmental load and economic value of concrete mixed with such are in high demand. In this study, A-BFS (Activator Blast Furnace Slag), which is mixed with an activator in order to induce early-age strength manifestation of BFS mixed concrete was used to execute a physical property evaluation of concrete. This study first conducted physical property tests for compression strength of concrete that partially replaced OPC (ordinary Portland cement) with A-BFS and executed a comparison/analysis with 100% OPC. It was thought that if concrete early strength is manifested through this process when applied to RC (Reinforced Concrete) building, at most a three to four day construction cycle would be possible, according to which the economic value of the construction period reduction was evaluated. For this evaluation, general apartment houses (Case 1) were taken as the evaluation subject, and for comparison, Cases 2, 3, and 4 were set up by the mix ratio of A-BFS, and the economic value evaluation range was established. As a result, it was found that Case 2 had no change from Case 1, while Case 3 saved about 106,654,762 KRW (Korea Won) and Case 4 saved about 159,982,143 KRW. © 2016 by the authors.

Jeong Y.-S.,Building and Urban Research Institute | Jung H.-K.,Building and Urban Research Institute
Advances in Materials Science and Engineering | Year: 2015

The use of the resilient materials in the radiant floor heating systems of reinforced concrete floor in apartment housing is closely related to the reduction of the floor impact sound and the heating energy loss. This study examined the thermal conductivity of expanded polystyrene (EPS) foam used for the resilient material in South Korea and analysed the thermal transfer of reinforced concrete floor structure according to the thermal conductivity of the resilient materials. 82 EPS specimens were used to measure the thermal conductivity. The measured apparent density of EPS resilient materials ranged between 9.5 and 63.0 kg/m3, and the thermal conductivity ranged between 0.030 and 0.046 W/(m·K). As the density of resilient materials made of expanded polystyrene foam increases, the thermal conductivity tends to proportionately decrease. To set up reasonable thermal insulation requirements for radiant heating floor systems, the thermal properties of floor structure according to thermal insulation materials must be determined. Heat transfer simulations were performed to analyze the surface temperature, heat loss, and heat flow of floor structure with radiant heating system. As the thermal conductivity of EPS resilient material increased 1.6 times, the heat loss was of 3.4% increase. © 2015 Young-Sun Jeong and Hae-Kwon Jung.

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