Ha-Young Song

Suggesting Solutions when Applying Building Information Modeling (BIM) to the Korean Construction Industry through Case Studies

When faced with new projects, such as high-rise, complex, free-formed, and sustainable buildings, numerous participants in the building Industry use Building Information Modeling (BIM) technology. In 2009, the use of BIM spread to more contractors than eyer before. This paper aims to study the definition and characteristics of BIM, and to analyze Korean BIM application problems. Solutions for the application of BIM to the Korean Construction Industry suggested, by studying cases from developed counties and from Korea.

An Experimental Study on the Influence of High Fineness Fly Ash and Water-Binder Ratio on Properties of Concrete

Recently, the press and institute recognized fly ash as it had excellent performance. Its research and applications are on the rise largely as a substitute for cement. On the contrary, it is in a situation that the regulation of high fineness fly ash remains at a low level. As for the fly ash in 3,000~4,500 cm /g class fineness regulated in KS L 5405, it is used by substituting it around the unit weight of cement 20%. Accordingly, the regulation in upper classification is in a situation of being insufficient. Therefore, this study aimed to establish 4000, 6000, and 8000 class of fineness of fly ash and three levels of substitute like 15%, 30%, and 45% in order to analyze the substitute and effect of water-binder ratio for fly ash that affected the properties of ternary system concrete. As a result of experiment by planning water-binder ratio for two levels like 40% and 50%, the more replacement ratio and fineness of fly ash increased in the performance not hardened, the more the fluidity increased. This study has found out that the air content decreased, and that there was setting acceleration and it decreased the heat of hydration. In addition, as for the strength properties in a state of performance hardened concrete, the more the replacement ratio and the ratio of water-binding mate- rials increased, the more it had a tendency of being decreased.

An Experimental Study on the Early Strength Development Properties of Concrete According to Curing Condition and Used Materials

The purpose of this study is to investigate the engineering properties of concrete for the early strength development. As a result of reviewing it by establishing each experimental factor and level, the cement had more excellent quality performance in CHC and HESPC than OPC. This study has shown that the PC series admixture was more excellent in side of elapsed time (aging) and early strength development than PNS series admixture. In addition, there was much difference according to the curing temperature, but the early strength development showed the considerable vulnerability in curing temperature below 12 C. To satisfy the strength requirements of 5 MPa/18 hr this study has shown that it needed the curing temperature over 17 C to the minimum in OPC, over 14 C in CHC, and over 11 C in HESPC. On the other hand, as to the strength properties according to W/C, the less W/C was, the more strength development was excellent. If this study is to be used in construction filed on a basis of this result, this researcher is considered as possible of the economic execution of con- struction by advancing the early strength and by the reduction of construction cost according to shortening construction duration.

Strength Properties According to the Conditions of Low Carbon Inorganic Composite Using Industrial By-product

The purpose of this study is to examine the potential for reducing the environmental load and gas when cement is produced by using cement substitutes. These substitutes consisted of blast furnace slag, red mud and silica fume, which were industrial by-products. The most optimum mix was derived when alkali accelerator was added to low carbon inorganic composite mixed with industrial by-product at room temperature. It is determined that hardened properties and the results of compressive strength tests changed based on CaO content, Si/Al, the mixing ratio and the amount of alkali accelerator, curing conditions and W/B. The results of test analysis suggest that the optimum mix of low carbon inorganic composite is CaO content 30%, Si/Al 4, the mixed ratio of alkali accelerator 50g:50g, the amount of alkali accelerator 100g and W/B 31%. In addition, if contraction is complemented, low carbon inorganic composite with superior performance could be developed.

An Experimental Study on the Properties of Concrete according to G/S ratio classified by Maximum Size of Coarse Aggregate

In this study, the experiment was carried out to investigate and analyze the influence of coarse aggregate`s mix ratio and maximum size on the properties of concrete. The main experimental variables were water/cement ratio 45% and 65%, coarse aggregate/fine aggregate ratio 90%, 130% and 170%, maximum size of coarse aggregate 15mm, 25mm and 40mm. According to the test results, the principal conclusions are summarized as follows. 1) The slump and flow of fresh concrete were found to be higher in the order of G/S ratio 170%, 130%, 90%, also in the order of maximum size 40mm, 25mm, 15mm. 2) The compressive strength of hardened concrete were found to be higher in the order of G/S ratio 170%, 130%, 90%, also in the order of maximum size 15mm, 25mm, 40mm.

A Study on the Engineering Properties of Ultra High-Strength Concrete Utilizing Crushed Sand

Recently, the demand of ultra high-rise building is on the increase in korea due to the rapidly changing movement in economic growth and the expansion of national infrastructure. At the same time, the tendency toward the amount used of concrete has greatly increased every year. In addition, as the seriousness of quantity demanded of aggregate is gathering strength, the active areas of research proceeds to do actively in every place in order to review the usability of crushed sand as a part of the countermeasures. And, it needs to establish the quality standard and service guide, etc. for the practical use. Accordingly, this study was to establish the ratio of water-binder materials as three levels like 23.5, 27.5, and 31.5%, and the replacement ratio as three levels like 0, 50, and 100% in order to define the engineering properties of ultra high-strength concrete using the crushed sand. This study was to examine it after establishing the combined condition by the substitute of the fine aggregate percentage and admixture. From the result of this research above, it may be summed up as follows. 1) The more the replacement ratio of crushed sand and the ratio of water-binder materials increased, the mon the fluidity decreased due to the decrease of irregular grain shape of sand and unit combined discretion. 2) This study found out that 100% of replacement ratio of crushed sand was almost similar level to the compressive strength of concrete using the natural sand.

Physical and Mechanical Properties of Magnesium Oxide Matrix depending on Addition Ratio of Magnesium Chloride

Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.

Physical Characteristic of Artificial Stone Using Waste Resources

Recently, the enviroment problem is serious due to the global warming phenomenon because of the greenhouse gas exhaustion. And it is the situation where the severity of the destruction of environment because of the indiscriminate picking of the,that is the raw material of the cement, limestone and aggregate and exhaustion of resource are emphasized. In addition, thus the cement reduction amount of use and substitute material research is the urgent actual condition with the gas emission, which here it is generated in conducting compression molding in the building stone manufacturing process performance degradation phenomenon and fire resistance, and problem of the durability. The ratio of the waste resources (the waste glass and waste porcelain) about the total volume select as 50, 60, 70, 80 (%) etc. and try to look into the characteristic of the artificial stone according to it at this research. and the subject for examination according to it is the flexural strength, compressive strength, specific gravity (density), water absorption, rate of aggergate on the surface etc. It was considered in the exterior material standard criteria to be reasonable. And. It was exposed to be the most superior in case of the waste Porcelain mixing ratio 70%, waste glass mixing ratio 70%, and waste glass + waste Porcelain 80%.

Physical Properties of Dredged Sand Treated by Washing and Sorting Dredged Soil

Most of the dredged sand generated from the sewage pipe maintenance project and the governments four-river project are disposed depending on abandonment and filling-up. This is caused by the lack of related recycling technology using dredged sand appropriately and high absorption rate and micro-particles of dredged sand producted from existing sand production system. Thus, this study carried out a quality assessment for the dredged sand produced through the optimum washing and sorting system supplementing problems of existing dredged sand production system as a part of research to examine performance of removing micro-particles and foreign substances. As a result of the assessment, the dredged sand produced through the cleaning and sorting system showed a wide quality improvement effect in absorption rate, 0.08 mm sieve pass amount, clay lump volume and organic impurity content, and it turned out to satisfy both the quality standards of this study, KS F 2573(recycled aggregate for concrete) and KS F 2526(aggregate for concrete) so it could be confirmed that it would be able to be used as an aggregate for concrete in the future.

A Study on the Choice of Optimal Mixtures and Sensibility Properties of High Strength Concrete and Mass Concrete to apply the High Rising Building

This study is to choose the optimal mixture and to analyze the sensibility properties of High strength concrete and mass concrete to apply the high rising building. The main experimental variables were water/binder ratio 31%, 33%, 35% and 37%, replacement ratio of fly ash 5%, 10% and 15%, in the high strength concrete and water/binder ratio 39%, 41% and 43%, replacement ratio of fly ash 10%, 20% and 30%, in the mass concrete. According to the test results, the principal conclusions are summarized as follows. 1) The slump(or slump flow) and air content of fresh concrete were found to be the highest in the elapsed time 30 minutes. 2) The optimal mixture conditions are W/B 40%, FA 25% in the mass concrete and W/B 33.4%, FA 15% in the high strength concrete. 3) The ranges of sensibility are satisfied in the moisture content ±1% and S/a ±2%