Earticle

The purposes of this study is investigating the variation of Find Pore Structure and the mechanical properties in heated temperature Using Nitrogen Adsorption method. As results of this study comprehended the characteristic of porosity of High-heated Concrete, the following can be summarized; Generally Pore Distribution Variation showed a tendency to increased affected by the influence of high water-cement ratios(W/C). On the whole porosity showed a tendency to decreased according as High-heated temperature irrespective of water-cement ratios(W/C). The compressive strength and the modulus of elasticity were degraded depending on a rise of heated temperature.

The purpose of this study is to evaluate the Chloride ion migration coefficient of High-heated Concrete by NT BUILD 492 method. To evaluate performance of surface 5cm incoming Chloride Ion, 2D-numerical analysis model (FEM) was developed. As results of this study was obtained as follows; The Chloride ion migration coefficient of High-heated Concrete were increased by heated temperature. In conclusion, the Chloride ion migration coefficient were affected by distribution of porosity and pore size.

The purpose of this study is to investigate the effect of different levels of cement replacement(0, 5, 10, 15, 20, 25%) by copper slag as admixture on the expansion of mortar bars containing reactive aggregates. The experimental program included expansion measurement of the mortar bar specimens, also the determination of the morphology and composition of the alkali-silica reaction products by using scanning electron microscopy(SEM), energy dispersive x-ray(EDX), and x-ray fluorescence spectrometer(XRF). The results indicate that more than 15% percent replacement of portland cement by copper slag stop deleterious expansion due to the alkali-silica reaction. Also it was found that the expansion rate increased with the increase of the CaO/SiO2 and CaO/(Na2O)e ratio from the comparison of the oxide compositions with the different levels of replacement by copper slag.

The purpose of this study is to investigate the properties of concrete with the kinds and addition of expansive dditives. 2 kinds of expansive additives produced in our country and 0, 10, 20, 30, 40% of ratio of addition rate are selected for this experiment. According to experimental results, flow, slump and air rate of concrete with expansive additives is nearly same with its of plain concrete and compressive strength, tensile strength of concrete with expansive additives at 28 days is higher than that of plain concrete. Therefore, The expansion concrete is able to manufactured so it consumes by restricted effects.

The following research has taken place from the buildings' that has been there between 20-40 years, located near the coastal areas and its level of flying salinity and effect elements are classified into its standard level, distance/range level, material level, direction level, region level, floor level and actual distribution of salinity content has been found. The buildings that are situated within 600m of the coastal area, which are ready to be demolished in Busan City, Nam-Gu, Su-young and Hae-woon-dae, such as apartments, hotels and long-term aged has been selected for the core test. From these selected buildings the core testing samples were drawn, an abscission took place in the interval of 10mm to 50mm depth from the surface and the following has been found from the each salt content level. From the selected 51 core test samples, the salinity level has been analysed and its result indicated that 14 samples (27%) fits under the regulated standard level of salt content of 0.3㎏/㎥ for the iron concrete, 8 samples (16%) leveled from 0.3∼0.6㎏/㎥, and the remaining 29 samples (57%) indicated fairly high level of 0.6∼5.5 ㎏/㎥ in salinity content level. And the salt content level from 20∼200m distance was at an average of 1.63㎏/㎥, and at 200∼600m distance showed 0.46㎏/㎥ salt content level, which indicates an obvious difference. The most suitable finishing material could be exposed concrete material and exposed finishing which indicated almost 2.0㎏/㎥ difference.

Sulfate attack is one of deterioration factors damaged to the concrete durability, especially magnesium sulfate corrosion has known that it arises more serious durability decline by generating de-solidation M-S-H gel. For the purpose of increasing resistance of the sulfate attack, pozzolan has been used, however, there is lake of study on the sulfate resistance of waste glass concrete contained waste glass powder. In this paper, the deterioration degree with digestion's days of waste glass concrete digested in magnesium sulfate solution is observed and analyzed, then compared to plain concrete and concrete contained fly ash and blast furnace slag powder.

This paper is to investigate the period of mild freezing and frost action in the period of cold weather concrete in Korea based on temperature data of Korea The period of mild freezing and frost action in the cold weather concrete was decided based on the code of Architectural Institute of Japan. According to the results, the mild freezing period was different with each region, and it was estimated about 20～70 days. It was increased in the southern region and coast district of Korea. Especially, it existed after the finishing day of cold weather concrete period. The period of frost action was estimated about 60～100 days and prolonged to the northern district, and it included the most part of cold weather concrete period. In some regions, it lasted after the end of cold weather concrete period by AIJ. Accordingly, it is necessary to prepare appropriate plan to prevent the frost damage at early age, even if the cold weather concrete period was finished .

The purpose of this study is to investigate the effect of different levels of average particle size and firing temperature by rice husk ash on Admixture of high strength concrete. The experimental program included compressive strength of the concrete specimens. The specimens werw made with nomal portland cement and pozzolan materials with various replacement ratio and with W/B ratio fixed 0.35. The results indicate that Firing temperature 600℃, it was the maximum value by rice husk ash as admixture of high strength concrete. And It was maximum value particle size by rice husk ash as admixture of high strength concrete is 30㎛. The concrete mixed rice husk ash was quite improved, and thereafter the investigation the effect of different levels of average particle size and firing temperature by rice husk ash on Admixture of high strength concrete.

This Study is to investigate the utilization of calcining oyster & mineral material(maecbansoek) powder as calcium binder. The results of this study is follow; (1) Flow of paste using of calcining oyster & mineral material(maecbansoek) powder is similar at all condition. (2) Initial setting time is decreased by increasing of calcining temperature and time. Especially, oyster powder of manufacturing at calcining temperature 1,000℃ & time 120min appeared flash setting property. (3) The compressive strength on age is improved according to increasing of calcining temperature & time. Therefore optimum manufacturing condition of oyster powder is deducted calcining condition 1,000℃․120min & mineral material replacing rate 40% as calcium binder.

Hwang-toh is a kind of metakaolin, which is one of the natural pozzolana, and mainly consists of SiO2, Al2O3 and Fe2O3. Activated Hwang-toh is so similar to the admixtures causing pozzolanic reactions. Therefore, the purpose of this study is to develop Hwang-toh as cement admixture, we examine basic properties of Blast-Furnace Slag cement mortar with Hwang-toh, and so we intend to propose a basic data to improve the possiblility of using Activated Hwang-toh as one of the natural resources. This study shows characteristics of compressive strength according to the replacement ratios of Hwang-toh powder through an experiment. Blast-Furnace Slag cement mortar mixtures were cast using 0, 10, 20 and 30% by volume replacement of cement with hwang-toh. As the result of this study, to be used Activated Hwang-toh, Compressive strength of mortar is decreased more than plain mortar.

The chloride ion migration coefficient of polymer modified cement mortar (PCM) used as patching repair materials to the deteriorated RC structure was tested by NT BUILD 492 method. To evaluate performance of repaired section against incoming Chloride Ion, 2D-numerical analysis model (FEM) was developed. The diffusion coefficient of chloride ion decreased in proportion to the polymer cement ratio. It became clear through the analysis of FEM model that the performance change over time after repair depend on the removal range of retrograded concrete and the time of repair application.

The purposes of this study are to evaluate the pore distribution change of PCM by carbonation through the nitrogen adsorption method and to construct the requisite data base for expecting the life expectancy and the durability of concreter structures. The following conclusions were obtained from a series of　experiments. PCMs have a high resistive　properties against carbon dioxide diffusion. The change of pore distribution of PCM before-after carbonation can be evaluated qualitatively through the nitrogen adsorption method

Recently, the industrial waste is scattered and one of the oyster also make the serious environmental contamination. So, the purpose of this study is investigating an utilization ability as calcium binder of the oyster which is an industrial by-product. According to the previous experimentation calcining condition strength of 1000℃(120min) is higher than any other conditions. So this study shows an effect that the oyster mixes with admixtures such as fly ash or blast furnace slag by rates (10%, 20%, 30%, 40%, 50%). The compressive strength and flow of the paste in mixing condition increase. Especially, when the oyster alternates the 50% of rate with blast furnace slag the setting time has more useful condition.

Recently, an ore of stone obtained from quarry lose its about 60% such as the muck and the stone-dust during the process of making the architectural block, the crushed aggregate and so on. A part of the muck is only reutilized for the crushed aggregate as road pavement materials, while the most of the muck in the shape of powder is mixed with water and then it is deposited in a sludge tank. The much in the shape of powder is called the stone-dust. If the stone-dust is discharged and sprayed, an ecosystem will have terrible damage because the seepage of surface water, the flow of ground water and the movement of air are not occurred smoothly by packing the void of soils. Therefore, the establishment of an efficient recycling plan are necessary through the improvement of engineering properties of the stone-dust. This study is to investigate the possibility of recycle and improvement for the Granite powder is sampled from quarry in Korea. The various strength tests are performed by use of the mixed soils with the Granite powder content ratio. As the result of various strength tests, the recycle possibility of the Granite powder is analyzed as subbase layer materials of the construction.

The air performance according to a substitution percent experimented S the assessment about the making of the repository catalyst and surface area S use the mixing metal oxidized substance to react for the purpose to develop an one's parent's illness weapon paint in the thorn light use the repository catalyst at the blast furnace-slag and remove VOCs with a air purification capacity NOx of the room. An air performance experiment according to the substitution percent of the repository catalyst and A physical characteristic experiment. The result to execute besides an air performance experiment We can get the conclusion following the case to be a wall accumulation of freight low with the blast furnace-slag use the TiO 2/S a synthesis repository catalyst TiO 2 powder to be made.

Recently among of many stages to progress successful building construction, design stage as the first of it is gathering strength, the importance about design engineer’s competency is recognized to make a progress for design business. In order to lead successful building construction not only design engineers as in the first stage of construction project but other competencies are also needed for work competency. Hence, drawing experts who have suitable ability for every each design stage will be choose from the first selection. However, research about standard which is to find out the actual thing of competency for drawing experts in certainly not enough. Therefore, the objective of this research to set up competency evaluation of drawing experts using by suggested items from previous study as competency evaluation items of construction engineer.

Traditionally, a domestic construction industry has recognized the relationship between a primary contractor and a subcontractor as a subordinated trade connection. To improve this unfair connection, the primary contractor and subcontractor’s relationship must be recognized as Co-Development, and a new construction circumstances are needed, too. To apply benefit sharing to this relationship for Mutual Corporation, this needs the application method which could be reflected the specific aspects such as construction production method and production organization. Therefore, this study is aimed for the suggesting of basic data for Benefit Sharing application in the domestic construction industry by researching the problems and Benefit Sharing application States.

The government is adapt with responsible supervisory system to prevent fault construction and make better quality, then it suggest construction supervision compensation criteria by notification of Ministry of Construction & Transportation. However, since there is still no budget for responsible service so it is not achieving purpose to make better quality of construction supervision service through proper service fee. Hence, this research is investigating actual conditions about compensation of construction supervision fee of 76 items of construction previous ordered from each own organizations. So, actual conditions analysis result, estimate standards of service compensation is different as every competent authorities at the same time controversial point is that basis amount of money of responsibility supervisory compensation is estimate average 10% low as construction supervision compensation criteria. Therefore, the uniformity of service compensation from each authorities or making suitable service compensation will be necessary to remedy against this kind of problems

Recently, the instruction of house ventilation system was necessary because of the recent construction trend and the legal ventilation frequency 0.7 point inside the house of common. It is general in the ventilation system that air supply and return to each room. But that system is not efficient in the economic and construction circle. So we study the instruction of unify ventilation system. The purpose of system is to compare the original ventilation system and unify ventilation system. The results which it applies from actual apartment site are as following. In the wind-amount test, unify ventilation system shows more wind amount than the existing facilities. Pressure loss shows the opposite results. This displays a more efficient ventilation ability and there is also an application possibility. Finally, we finds unify ventilation system's a new possibility and we recognize that more detailed-tests are required to unify ventilation system's practical use.

The purpose of this study is to suggest advanced applications of life cycle cost analysis for evaluating various alternatives in construction projects. For this study, we have surveyed and analyzed current laws and regulations, and state-of-the-art methods on the life cycle cost analysis for better cost-benefit analysis framework.

Domestic by opening of world construction market with recent FTA should be achieved systematic action that of exoteric surrounding construction environment to inculcate this because consciousness structure unpreparedness of legation fields about quality is expose for hindrance factor for QI in construction spot by quality and organization management official important thing for building company's QI because conquest is possible through QI of construction to possess government official and international competitiveness of customer satisfaction by offering consumer building of change and good quality rapidly, organization's CEO determination must become side improvement the formation government official enemy, and when inspect by each process, responsible persons participate cooperation enterprise space-time. To improve this because complete charge department for quality control appears that organization management need complete charge department being expose by greatly unprepared misgovernment in heavy hydrogen building company, expense that CEO under direct control histiocyte modeling air with AHP analysis is economical will be cost, but is construed can bring excellent effect in operation management side of quality and organization such as cost-cutting effect in maintenance side and I should do so that can occupy competitive power high position with tissue at active quality complete charge deputy.

The mass housing supply policy of the government has resulted in the customer-centered market, and thereby the age of quality competition in the industry. In line with this trend of quality competition, therefore, this preliminary study aims to investigate the requirements of housing product planning to live up to the needs of customers in terms of quality, and thus analyze the types of quality differentiation of a housing product unit in our housing market. For this, established was the quality factor classification system of apartment units, and it turned out that many cases attempted differentiation in such ways as merely using luxurious finishing materials and instantly popular environment-friendly materials, and combining partial and limited household items with architectural elements of the facility system. The result of this study shows that the differentiation plan of housing product should be customer-centered, and therefore, focus on quality differentiation through organic combination of architecture-oriented plane and interior elements with technology-oriented facility and product elements. Hereby, in the future, housing product planning should include sustainable differentiation plans with reconsideration of concepts that customers have, and the needed procedure.

The Korea National Housing Corporation contributes activated value engineering(VE) how to hold a plan VE competition every year. This study introduced VE working results to execute effectively plan VE competition of the Korea National Housing Corporation. A VE Job Plan was based, and the distinction on choice process of phased VE Job Plan was chosen in the stage of VE working process. The executed results due to VE proceeding about " the new construct field of apartment, A-14, Woonjeongjigu, Paju" as the project of a plan VE competition 2006 was to enforce 163 works of functional definitions, 333 items of creating ideas, and 193 achievements of ideas. Besides, VE was proposed about 46 works of increasing values and cost reduction for 103 works and 10,040,000,000 won.