• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.269-274
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• 2000

As a result of the reduction of natural aggregate, most of developed country have been studied the utilization of Blast-furnace Slag(BFS) as aggregate of concrete. bur, in korea there are only basic study about these even though other country are using Blast-furnace Slag production of Ready Mixed Concrete. According, in this study, we carried out fundamental experiments in order to know the material properties of BFS and possibilities of the BFS as fine aggregate of concrete. It is included that analysis concerning material properties of BFS as like specific gravity, absorption. unit weigth, grading including investigation of the surface shape by SEM, also, analysis concerning properties of concrete with BFS as like air-content surface slump. compressive strength .etc.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.122-123
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• 2021

This study examines the performance of pretreatment process system as the initial construction stage of the pretreatment process system to use CGS, a by-product generated in IGCC, as a concrete fine aggregate of construction materials. The process undergoes a grinding process capable of grinding to a predetermined particle size during primary grinding and a sorting plant through sieve grading of 2.5 mm or less for particle size correction. Afterwards, it is hoped that the use of coal gasification slag of Korean IGCC as a fine aggregate for concrete will be distributed and expanded by producing quality-improved CGS fine aggregate using water as a medium for removing impurities and particulates.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.97-100
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• 2005

The purpose of this study is to research the basic property of mortar as the grading distribution of copper slag used as fine aggregate and the results are as follows. The compressive strength of mortar as the size of largest diameter of copper slag granule is the highest when the largest size is in 2.5-5mm, and flow of mortar is in proportion to the size. As the largest size of copper slag particle is under 2.5mm(Type 1) the compressive strength and flow is higher as the big granules is more included than small ones. As the largest size of copper slag granule is under 5mm(Type 2) the compressive strength and flow is similar to situation of Type 1, except compressive strength is higher as the percent of the size of granule in $2.5\~5mm$ is under 35$\%$. F.M.(Fine Modulus), compressive strength and flow is relative each other except the batch with 2.5$\∼$5mm granule size of copper slag.

• Computers and Concrete
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• v.13 no.2
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• pp.187-207
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• 2014

This paper mainly discusses the influence of the aggregate properties including grading, shape, content and distribution on the chloride diffusion coefficient, as well as the initiation time of steel corrosion from a probabilistic point of view. Towards this goal, a simulation method of random aggregate structure (RAS) based on elliptical particles and a procedure of finite element analysis (FEA) at meso-scale are firstly developed to perform the analysis. Next, the chloride diffusion coefficient ratio between concrete and cement paste $D_{app}/D_{cp}$ is chosen as the index to represent the effect of aggregates on the chloride diffusion process. Identification of the random distribution of this index demonstrates that it can be viewed as actually having a normal distribution. After that, the effect of aggregates on $D_{app}/D_{cp}$ is comprehensively studied, showing that the appropriate properties of aggregates should be decided by both of the average and the deviation of $D_{app}/D_{cp}$. Finally, a case study is conducted to demonstrate the application of this mesoscopic method in predicting the initiation time of steel corrosion in reinforced concrete (RC) structures. The mesoscopic probabilistic method developed in this paper can not only provide more reliable evidences on the proper grading and shape of aggregates, but also play an important role in the probability-based design method.

• Journal of Ocean Engineering and Technology
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• v.4 no.1
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• pp.71-80
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• 1990

We experimented the physical property of the porous concrete by changing the water cement ratio, when the aggregate ratios are 1:5 and 1:7 separately. And then we received the results as follows. The bigger, the coarse grading of the porous concrete is, the more sensitive to the water cement ratio, the porous concrete becomes. And if we think over its compressive strength, the coarse aggregate which has 5-15mm width is most appropriate. So we concluded that when its compressive strength, permeability coefficient and its unit weight are $50kg/cm^{2}3cm/sec$ and $1900kg/m^{3}$ respectively, the water cement ratio which has 35-37% width is most appropriate, too. And its compressive strength and unit weight show that they are about a quarter and three quarters respectively about the conventional concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.103-110
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• 1997

The objective of this study is to provide the information on the small-scale model mix proportion when the behavior of prototype concrete pavement is studied through small-scale model experiments. However it is difficult to obtain a model material to simulate the prototype concrete by scaling the individual components according to the laws of similitude. In this paper, the stress-strain behavior in uniaxial compression is used as a means to correlate materials similitude between the prototype and the model concrete. Based on th results of experiments, We compared the stress-strain curves of prototype and model concrete mixes using a nondimensional basis. In order to simulate the stress-strain curves of prototype concrete, it is important that various mix as of model concrete selected properly which are varied from aggregate grading, cement-aggregate and sand-aggregate ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.60-61
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• 2020

In this study, the recycled fine aggregates produced from the waste concrete by using Jaw crusher depending on crushing gap of Jaw crusher were studied to offer a solution for recycled fine aggregate for concrete. The results of the experiment showed that the factors that influence grading and water absorption ratio, density and grain shape were significantly characterized by the generation of the particulate matter and the crushing shape of the aggregate.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.37-42
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• 2011

In this study, it is analyzed that mechanical properties and required strength of porous concrete according to the mixing ratio of cement, fine aggregate, and water/cement ratio in order to evaluate mechanical properties of porous concrete using recycled asphalt aggregate. Recycled asphalt aggregates of 13 mm were used without modification of aggregate grading to extend porous concrete application. The water/concrete ratio was poor mix and the range of compressive strength was 18.2 to 19.5 MPa. The average value of permeability showed 8.0E-02 cm/sec.

• Ocean and Polar Research
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• v.33 no.1
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• pp.85-97
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• 2011

The tidal flats of Korea today have reduced by 40% in size compared to 1964. To manage this important habitat properly, development of well-organized and nationwide-applicable grading systems is required. There have been several assessment systems proposed previously in Korea, but they are critically flawed in that selected biological indicators are not adequate and grading criteria are obscure and arbitrary. We reviewed the indicators used in these previous evaluation systems (e.g., diversity indices, quantity and quality of benthic macrofauna, halophytes, water birds, etc.) and subsequently proposed new indicators and an improved grading scheme. For the quantitative assessment of macrobenthic community, biomass reflecting production and ecosystem function is recommended over density, which is much less discriminatory among habitats. Of biodiversity indices used, within-, between-habitat and regional biodiversity indices that accurately reflect sampling efforts are suggested. In addition, we proposed to include species rarity, ecosystem engineers, and the ecological quality index ISEP (Inverse function of Shannon-Wiener Evenness Proportion). As for halophytes, their low spatial coverage on benthic habitat suggests that their presence can be used as an ecological indicator of benthic habitat, regardless of their protective status. We stress the need to introduce 1) quantile approach for quantitative indicators (e.g., diversity, biomass, etc.) in relation to grading, 2) presence-absence approach for spatial or aggregate indicators (e.g., boundaries of halophytes and feeding ground of water birds) and 3) benthic habitat mapping that combines all of these indicators.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.576-580
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• 2001

The amount of the waste foundry sand(WFS) produced in Korea is over 700,000 ton per year, but most WFS buries itself and only 5~6% or total WFS is recycled in the way or mixing as fine aggregate for construction materials. A bY-product, WFS produced from a foundry may affect our environmental contamination if it is discharged without proper waste disposal in Korea. Therefore in this study, we performed the fundamental research about specific gravity, absorption, grading curve, finesse modulus of WFS, different aggregates and the flow and the compressive strength of mortar with WFS replaced as fine aggregate, the workability and compressive strength of concrete with WFS as fine aggregate aimed at the specified strength of 270 kgf/$\textrm{cm}^2$, and then optimum mix proportion of concrete was determined