• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.503-506
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• 2005

Recently, corrosion of reforcement of reinforced concrete structures and carbonation is raised problem of durability because of exhaustion of river sand and rapid increase of sea sand and also, concrete structure of sea environment is attacked to combined deterioration according to penetration of chloride ion and carbonation, change of temperature, repetition of dryness and wetness. Therefore, In this study, data base were presented to solve the problem about using sea sand to concrete structure situated in combined deterioration environment by exposuring concrete specimen contained chloride ion under the individual and combined deterioration.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.147-152
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• 1998

This study is to investigate the application of concrete with crushed sand on site. As a result, it is showed that the combined sand mixed with sea sand is very desirable for obtaining workability and strength of concrete, and the optimal replacement percentage of crushed sand is 50% with sea sand. After all, the crushed sand could be sufficiently used as a fine aggregate for concrete in the aspect of economical efficiency and quality, but the particle shape and microsand passing No.200 sieve should be firstly improved for increasing workability of concrete on site.

• Journal of the Korea Institute of Building Construction
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• v.3 no.3
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• pp.107-112
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• 2003

This study is to investigate the properties of concrete with crushed sand on site and to propose a quality guideline for its use as artificial sand and concrete. From our experimental result in laboratory and site, we found that demand water of concrete with crushed sand for target slump increased by 18kg/m3 compared to mixed sand and l8kg/m3 compared to sea sand respectively. The compressive strength increased by around 3∼6% when compared to concrete with sea sand. Accordingly, our study showed that the combined sand mixed with sea sand would be desirable to obtain workability and strength of concrete including dry shrinkage and bleeding test. Furthermore, the optimal replacement percentage of crushed sand was 50% with sea sand. As such, crushed sand would be sufficient as fine aggregate for concrete in terms of economic efficiency and quality. Crushed sand, on the other hand can only be used as fine aggregate when VFS(Very Fine Sand) is below 3.5 percentage of weight of sand and particle shape is above 55 percentage. Also, the particle shape and microsand passing NO.200 sieve should continually be improved to increase workability of concrete on site.

• Journal of the Korea Institute of Building Construction
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• v.3 no.4
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• pp.79-86
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• 2003

The purpose of study is to offer base data for high fluid concrete mix property, as grasp effect of aggregate to reach much more effect for producing high fluid concrete. For this study, there are three types of combined aggregates, river sand + river aggregate(type A), river sand + crusted aggregate(type B), washed sea sand + crushed aggregate(type C) and take a factor, water-contents, water-binder ratio and S/a. And so, we had following conclusion, resulting application-ability of high fluid mortar by K-slump tester to use a handy consistency measuring instrument. And so, we had following conclusion, resulting application-ability of high fluid concrete by K-slump tester to use a handy consistency measuring instrument. 1) In cafe of regular water binder ratio, high fluid concrete suffered much effect of combined aggregates and water binder ratio. Range of water binder ratio by combined aggregates is w/b 0.4 downward(type A and B), w/b 0.35 downward(type C). 2) Water contents to need for producing high fluid concrete is minimum 170kg/$\textrm{m}^3$ without regard to combined aggregates. 3) The effect of S/a on high fluid concrete by combined aggregates is approximately S/a 50% (type A and B), s/a 50-55% (type C). 4) Consistency measuring of high fluid concrete by K-slump tester is possible and first indication value, high fluid concrete can be produced, is 6~10.5cm.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.247-252
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• 2017

The aim of this research is the feasibility analysis of the reject ash premixed cement mortar with combined aggregate. Namely, for the combined aggregate with two different qualities of aggregates, a fundamental properties of cement mortar was evaluated depending on various replacing ratios of reject ash(Ri). According to the experimental results, the combined aggregate consisted with low-quality aggregate and sea sand did not change the flow value depending on the reject ash while the combined aggregates consisted with low quality aggregate and sea sand; and consisted exploded debris sand and sea sand the increasing reject ash increased the air content with increased replacing ratio of reject ash. In the case of compressive strength, as the replacing ratio of reject ash was increased, the compressive strength was increased. It is considered that when 5% of reject ash replacing ratio made similar quality of cement mortar with favorable quality aggregate, hence, it can be suggested that 5% replacement of reject ash for desirable fluidity and compressive strength of concrete.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.45-51
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• 2008

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.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.551-562
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• 2021

In this study, to suggest an efficient method of using coal gasification slag(CGS), a byproduct from integrated gasification combined cycle(IGCC), as a combined fine aggregate for concrete mixture, the diverse performances of concrete mixtures with combined fine aggregates of CGS, river sand, and crushed sand were evaluated. Additionally, using CGS, the reduction of the hydration heat and the strength developing performance were analyzed to provide a method for reducing the heat of hydration of mass concrete by using combined fine aggregate with CGS and replacing fly ash with cement. The results of the study can be summarized as follows: as a method of recycling CGS from IGCC as concrete fine aggregate, a combination of CGS with crushed sand offers advantages for the concrete mixture. Additionally, when the CGS combined aggregate is used with low-heat-mix designed concrete with fly ash, it has the synergistic effect of reducing the hydration heat of mass concrete compared to the low-heat-designed concrete mixture currently in wide use.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.169-180
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• 2024

In this study, to suggest an efficient method of using coal gasification slag(CGS), a byproduct from integrated gasification combined cycle(IGCC), as a combined fine aggregate for concrete mixture, the diverse performances of concrete mixtures with combined fine aggregates of CGS, river sand, and crushed sand were evaluated. Additionally, using CGS, the reduction of the hydration heat and the strength developing performance were analyzed to provide a method for reducing the heat of hydration of mass concrete by using combined fine aggregate with CGS and replacing fly ash with cement. The results of the study can be summarized as follows: as a method of recycling CGS from IGCC as concrete fine aggregate, a combination of CGS with crushed sand offers advantages for the concrete mixture. Additionally, when the CGS combined aggregate is used with low-heat-mix designed concrete with fly ash, it has the synergistic effect of reducing the hydration heat of mass concrete compared to the low-heat-designed concrete mixture currently in wide use.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.138-139
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• 2018

This study is a basic review of the basic characteristics of mortar as a result of the use of concrete as a fine aggregate for CGS(coal gasification slag) generated from the IGCC(integrated gasification combined cycle). The analysis shows that CGS and crushed sand + seal sand mix is the best combination of CGS combined with about 75 % of CGS based on the effects of promoting liquidity and strength. This is expected to be a positive factor in securing the strength and flexibility of concrete given the optimal mix of CGS, and may also contribute to the improvement of quality.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1458-1464
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• 1999

The whole body of three species of fishes, raw anchovy (Engraulis japonica), big eyed herring (Harengula zunasi), and northern sand lance (Ammodytes personatus) catched at the south adjacent coast of Korea, were analyzed for extractive nitrogen, free amino acids, combined amino acids, ATP and its related compounds quaternary ammonium bases, and guanidino compounds using specimens collected in May and July 1991, and the composition of these nitrogenous components were compared with each other. The contents of extractive nitrogen in anchovy, big eyed herring, and northern sand lance were 633 mg, 601 mg, and 455 mg/100 g, respectively. Thirty-one or thirty-two kinds of free amino acids were found in the extracts of the three species of fishes. Histidine, taurine, alanine, leucine, carnosine, glutamic acid, and lysine were the major free amino acids in every sample. The composition of the major extractive components such as free amino acids, combined amino acids, ATP and its related compounds, TMAO, and creatine in the extracts were similar to each other, but their contents were some different individually.