• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.449-456
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• 2013

This study was carried out to assess the suitability in terms of the standards of material quality of basalt aggregates from JEJU Island as a source for concrete aggregate. Quality assessments on the basalt aggregates were performed to assess the soundness of coarse aggregates using sodium sulfate solution, aggregate crushing test, and Los Angeles abrasion test. In addition, XRD, XRF, porosity, and compressive and tensile strength tests were performed to analyze the chemical components and the mechanical properties. In general, the mechanical properties of basalt aggregates from some areas did not meet the Korea Standards (KS), but the levels of compressive and tensile strength were higher than those of granite, andesite, and sandstone of other regions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5551-5557
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• 2012

Sedimentary rocks dug up in construction fields are mostly stockpiled for landfill disposal, leading to an increase in construction costs and construction inefficiency. After screening, some of the sandstone can be used as aggregate; however, most of the shale ends up as industrial waste in practice. In this study, to stabilize the demand and develop resources for alternative aggregates of concrete, the potential use of shale, which is widely distributed in the Daegu-Kyeongbuk region, as a concrete aggregate was evaluated. Red and black shale exported from a Daegu excavation site was selected for use in the experiments and evaluated by comparing with hornfels, which is widely used as a coarse aggregate and is a type of andesite and metamorphosed sedimentary rock. The physical properties of the aggregate were evaluated in accordance with the test methods of KS F 2527 "crushed concrete aggregate," and the compressive strength against the shale aggregate replacement ratio was measured. The compressive strength of the concrete after 28 days was 30.8 MPa when the black shale replaced 100% of the aggregate in the concrete and 31.1 MPa when the red shale replaced 100% of the aggregate in the concrete. Compared with the compressive strength of 37.5 MPa for concrete prepared by using plain aggregate, using shale as a substitute for the aggregate produced an average compressive strength that was 82% of normal concrete.

• International Journal of Highway Engineering
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• v.3 no.2 s.8
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• pp.103-112
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• 2001

This study was performed to evaluate applicability of recycled aggregates as subbase and surface concrete materials for cement concrete pavement. Laboratory compaction test, CBR test and plate load bearing test were conducted to evaluate applicability for pavement subbase materials. Recycled concrete for surface course was manufactured with a design strength of $280kgf/cm^2$. Normal coarse aggregate was substituted with recycled aggregates with five different ratios, 0%, 20%, 40%, 60% and 80% for recycled concrete mixes. Fresh concrete Properties, concrete strength properties for the five substitution percentages of recycled aggregates after 28-day curing and freezing-and-thawing resistance were evaluated experimentally. Based on the experimental results, it was concluded that the recycled aggregate was the material good enough to use for subbase material, and 40% or lower substitution ratio was an appropriate percentage of recycled aggregates replacement for surface concrete.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.581-588
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• 2009

An amount of electric arc furnace slag, by-products generated in iron manufacture, is being increased. Therefore, it is required to recycle the electric arc furnace slag. Currently, it is possible to use the electric arc furnace slag as the aggregates of the concrete through the insurance of volume stability but not in the past because of the expansibility of f-CaO and f-MgO. In this study, simple beam tests via Ichinose method were performed to estimate the bond properties of reinforced concrete (RC) beams using the electric arc furnace slag. The results of the test showed that the showed that specimens using the electric arc furnace oxidizing slag aggregates have similar or more bond capacity relative to the specimen of natural aggregates. Especially, bond capacity of the specimens using the slag aggregates was almost one and a half times higher than a specimen using natural aggregates.

• Resources Recycling
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• v.25 no.2
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• pp.49-59
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• 2016

Steel slag is being recycled into industrial by-products for civil generated inevitably in the seasonal course, road and cement raw materials. However, the field of recycling most of the bottom portion is concentrated in the areas that are required to take advantage of the situation in various fields taking advantage of the steel slag. But various studies to take advantage of the steel slag as aggregate for concrete made for limiting slag was a situation that most of the studies are incomplete research on the suitability of as aggregate for concrete practical relates to an expandable suppressed. In this study, the separation of the slag aggregate according to the production methods to assess the feasibility aggregate for concrete aggregates, including through Steel making slag, a total of seven kinds of steel slag aggregate. Studies show that ordinary concrete, steel slag aggregate for aggregate and on the equally to take advantage of grading, chloride content standards such as to what is lacking, although appropriate aggregate of concrete include the deployment of only in special sectors through the combination was assessed to have a very high.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.251-252
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• 2010

In this study, the basic properties of high performance concrete, to used oxidized electric-furnace-slag(EFS) aggregate, were examined. So we presented the possibility of using ㄸ EFS as concrete's aggregate.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.597-607
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• 2002

Electric arc furnace and converter slag are produced by about 6 millions tons in Korea at 2000 year. But compared with blast furnace slag, those are utilized only in unvalued material like landfill and road construction. There are unstable materials, like free CaO, in electric arc furnace and converter slag at steel-manufacturing process. This might cause volume expansion in concrete, if electric arc furnace and converter slag aggregates were used in concrete. This expansion may reach to crack or collapse of concrete. It is therefore settled by standard specification for concrete that electric arc furnace and converter slag aggregates have not to use in concrete. First of all, volume stability and stabilized process should be solved in electric arc furnace and converter slag aggregate to use in concrete. In this study, 6 types of aging are evaluated for effects of stabilization to reduce the expansion of electric arc furnace and converter slag. h converter slag aggregate, these types of aging are not good for volume stability for concrete aggregate, and even if converter slag aggregate is treated with aging, concrete with it has some problems that strength is reduced with curing days. But in electric arc furnace slag aggregate treated with hotwater and steam aging, the expansion of electric arc furnace slag aggregate is reduced about two times than that of converter slag aggregate, and electric arc furnace slag aggregate concrete has good results in strength compared with control concrete using crushed stone.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.589-599
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• 2007

For the preliminary judgement on the chemical stability of concrete aggregates mixed with cement paste, ASTM C 295 method can be applied prior to the long-term chemical test methods. By using this standard test method, the petrographic study on the appropriateness of natural KEDO aggregates for concrete was carried out. With the natural gravel and sand aggregates, the polarized microscope, stereoscopic microscope, and X-ray diffractometer were used for examination. The result shows the 23% of gravel aggregates and 5.1% of sand aggregates are chemically unstable. To select the favorable KEDO concrete aggregates, it is required to exclude the highly metamorphosed rocks, acidic volcanic rocks, highly foliated rocks, and expansive rocks identified from mortar-bar test. Further chemical test and mortar-bar test method integrated with this study is recommended for the suitability assessment of natural KEDO concrete aggregates.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.95-104
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• 2005

The research conducted to study the potential practicability of recycled aggregate concrete by analyzing the characteristics of concretes made of recycled quality aggregates produced by wet and dry process has found the following results. The air content of recycled aggregate concrete increased with increase of the substitut on rate due to mortar included while producing recycled aggregates. However, the concretes with aggregate produced by dry process had relatively low rate of increase in air content. The slump showed generally decreasing trend as the substitution rate of recycled aggregate increased regardless of the wet or dry process. It was assumed that the mortar particles remained in recycled aggregate absorbed the surplus hydration in concrete and decreased fluidity The compressive strength generally decreased as the substitution rate of recycled aggregate increased, however there was an increasing trend as well due to decreasing effect of water-cement ratio when the substitution rate of recycled aggregate reached 25, 50% after mix. This phenomena also appeared in early age, which meant that recycled aggregate concrete should not be retarded in setting when applied in the field. The tensile strength also reached the maximum when wet or dry recycled aggregate replaced with 25%. To conclude, recycled aggregates for concrete produced by wet or dry process are expected to demonstrate essential characteristics of concrete without significant decline in physical or dynamic quality when the substitution rate is below 25% although there are variations subject to water-cement ratio. However, slight differences are expected due to types of recycled aggregate and physical quality.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.79-87
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• 2012

Recently, Development of substitution aggregate is urgently needed because aggregate shortage is continuing due to the exhaustion of natural aggregate and strict restrictions of environment in construction industry. Therefore, This paper was examined the fundamental properties for application of FINEX slag by finex process as fine aggregate for concrete. Through this study, we propose the practical method of FINEX slag as fine aggregate for concrete.