• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.39-43
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• 2003

Chloride ions are considered to be the major cause of steel corrosion in concrete structures exposed to seashore environments and also permeation of chloride is controlled by chloride diffusion. Therefore, the study on chloride diffusion of concrete have been done so far by many researchers. It is reported that coating material as surface covering material is effect about deterioration of salt damage and carbonation, therefore these materials are important in durability of concrete structure. In this study, corrosion characteristics of reinforcement concrete according to types of surface covering material were evaluated by water-cement ratio, chloride penetration by age on the corrosion area rate and mass decrement of reinforcement. And it is considered that the result of this study on application of the corrosion characteristics of reinforcements under salt damage environmental will be suggested as fundamental data of control performance of salt damage. It is performed that comparison and examination of control performance of salt damage by the corrosion characteristics under salt damage environmental.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.137-146
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• 1995

Twenty(20) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceilings were investigated for asbestos content in bulk material by polarized light microscopy and for airborne fiber concentrations in buildings by phase contrast microscopy. In addition, such building-related variables as building age, numbers of traffic, airflow, surface conditions of the ceiling, temperature, and humidity were studied for any correlation with airborne fiber concentrations. The results were as follows: 1. Chrysotile asbestos was found in two bulk samples with 3-5% content and with <1%in one sample out of total 20 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The ceiling surfaces were very friable in 16 buildings and were relatively hard in 4 buildings. The friability of the surface material was dependent upon the type and the amount of binder that had been mixed with the sprayed-on surface material. 3. Airborne fiber concentrations were log-normally distributed and the geometric mean(geometric standard deviation) fiber concentrations in the underground parking lots, inside buildings, and outdoor ambient air were 0.0063(1.97)f/cc, 0.0068(2.29)f/cc, and 0.0033(2.36)f/cc, respectively. 4. No significant relationship of airborne fiber concentrations and all building-related variables studied except humidity was found. The results of this study suggest that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos. Since most of the ceiling surfaces surveyed were very friable and poorly maintained and the airborne fiber concentrations were relatively high, there is a possibility of asbestos fiber contamination in these buildings, particularly at those buildings with asbestos-contaminated surface material. Since poorly maintained surface conditions were thought to be a source of high airborne fiber concentrations, there is a urgent need of a systematic operation and maintenance program. Further study of non-occupational asbestos exposure in general population utilizing advanced analytical technique such as transmission electron microscopy is highly recommended.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.54-55
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• 2018

Reinforced concrete is a building material that is generally used in modern society. Securing the performance of reinforced concrete is directly connected to the durability and longevity of the building. One of the major factors that deteriorate the durability of concrete is harmful ion. Recently, the quality and improvement method of reinforced concrete for penetration of harmful ion has been studied. In this study, the bead type ion exchange resin is substituted for 0%, 3%, and 6% of the fine aggregate volume in the mortar. The speciments underwent underwater curing and were checked for compressive strengths of 3 days and 28 days. From the results of compressive strength, it can be seen that the higher the substitution ratio of the ion exchange resin, the lower the early strength and long-term strength development, especially the early strength development.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.143-148
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• 2007

Recently indoor air pollution caused by exposing hazardous chemicals (VOCs, formaldehyde) due to undiscriminated use of new construction materials and air-tightness to save energy is becoming a big issue. We have developed technologies to estimate the amounts of contaminants from constructions materials and method. We have further developed construction technologies to reduce and characterize these contaminants. The developed technologies were then refined to eliminate defects through considering field applicability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.67-70
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• 2011

The effect of column shortening is a major consideration in design and construction of tall buildings, especially in concrete and composite structural systems. To avoid unexpected demage in structural and nonstructural elements, differential shortening between vertical members resulting from differing stress levels, loading histories, volume-to-surface ratios and other factors in a high-rise building must be properly considered in the design process. This paper represents analyzed and measured shortening results of RC cores and columns at the 72 story Haeundae I'Park. It shows that WACS program based on ACI and PCA material model is effective for the prediction of column shortening.

• Journal of the Korea Institute of Building Construction
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• v.1 no.1
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• pp.135-142
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• 2001

This study is for the investigation of form using the aluminum-compound metal frame(Aluminum frame reinforced panel : AFR panel) which is improved in the capacity in the wall-concrete structure in steal of using the existing form which has problems such as, excessive exposure of cement, the loss of labor when it is constructed or disjointed, and it's economical efficiency compared with that of EURO Form. AFR panel passes the KS F 8006 test, and as a result of field test, it's displacement is satisfied with Specification. And using AFR panel is more economical than that of EURO Form because saving labor cost which plays a major part in cost saving in formwork is more effective in retrenching total cost than increment of material cost.

• Korean Journal of Materials Research
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• v.27 no.7
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• pp.353-358
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• 2017

Recycled cenosphere, which is a hollow shaped particle from fly ash, has become attractive as a building material due to its light weight and excellent heat insulation and soundproof properties. In this paper, we investigated the effect of cenosphere size on the physical and optical properties. High brightness of cenosphere as raw material is required for a wide range of ceramics applications, particularly in fields of building materials and industrial ceramic tiles. Cenospheres were sorted by particle size; the microstructure was analyzed according to the cenosphere size distribution. Cenospheres were generally composed of quartz, mullite, and amorphous phase. Colour measurement corresponding to chemical composition revealed that the contents of iron oxide and carbon in the cenospheres were the major factors determining the brightness of the cenospheres.

• Journal of the Korean GEO-environmental Society
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• v.17 no.6
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• pp.5-12
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• 2016

This paper deals with the result of thermal resistance test with backfill materials as bottom ash by using backfill material. Bottom ash, one of coal ashes, can be reused to replace sand because of its similar engineering properties. But without considering the thermal property, the abuse of bottom ash resulted in damage for existing structures. To investigate the thermal conductivity of bottom ash, laboratory tests for thermal resistance of that were carried out in this study. Thermal properties of bottom ash was compared with those of in-situ soil, sand, backfill material which can be applied as filling material. The tests were classified by water contents defined as the major influence factor. The beneficial use method of bottom ash was suggested as backfilling material.

• Journal of Construction Engineering and Project Management
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• v.3 no.4
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• pp.20-25
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• 2013

Variation in construction means modification of design, changes in quality, quantity of work including the alteration of standard of materials or goods to be used in the work and the removal from site any kind of material not in accordance in the contract. In Ghana, Variation order has become major issue in the construction industry. This had resulted in cost overruns, delay and in some contracts dispute, between parties. The aim of this paper was to identify the root causes of variation; effects of variations on projects in Ghana and the means of reducing the impact of variation order. The method of the study involved literature review, primary data collection, interview and closed - ended- questionnaires. Mean Scores Method was used to rank the identified factors causing variation. Analysis Of Variance Test was use to test for the significant difference between means among the professional groups. The study revealed that most causes of variation were change of design by client and inadequate working details. Establishment of oversight project management committee and flow of information were identified as means of controlling variations during project administration.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.597-601
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• 2006

There are considerable amount of man power and time spent for analysis and selection of various materials due to the inadequate application system and rapid searching process of material related information in each stage of building production process. Also, due to the insufficiency in recycling system of important information created for each process, they are hoarded at each task stage and project completion. As a result, because of the repetition of the similar/identical tasks on each process, it is the major reason for impeding the efficient employment of manpower of the company and decreasing competition of the company. Moreover, in selecting finish material in the project field, there are many difficulties due to the lack of technical information such as product characteristics and field applications. The construction quality also affects the profit and loss of the product which calls for a need to develop continued information management system that the finish material related examples could be shared in real time. The objective of this study is to propose a building finish material information which the real time research and application is possible to raise the productivity. TO do this, the current material information task status analysis and questionnaire research should be conducted to understand the demand of system development and reflect the result onto the system for easy access and application. Therefore, the building finish material information system for enhancement of productivity of construction task proposed in this study is expected to be utilized in enhancement of construction quality, maximization of company profit, and strengthening of company competition.