• Structural Engineering and Mechanics
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• 제90권5호
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• pp.467-480
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• 2024

The mechanical properties and durability of concrete pavements may be degraded in extreme situations, resulting in the need for partial repair or total replacement. During the past few decades, there has been a growing body of research on substituting a portion of Portland cement with alternative cementitious materials for improving concrete properties. In this study, two different configurations of powdered and granulated blast furnace slag were implemented, replacing fine aggregates (by 12 wt.%) and Portland cement (by 0, 20, 40, and 60 wt.%) in the making of roller-compacted concrete (RCC) mixes. The specimens were fabricated to investigate the mechanical properties and durability specifications, involving freeze-thaw, salt-scaling, and water absorption resistance. The experimental results indicated that the optimum mechanical properties of RCC mixes could be achieved when 20-40 wt.% of powdered slag was added to concrete mixes containing slag aggregates. Accordingly, the increases in compressive, tensile, and flexural strengths were 45, 50, and 28%, in comparison to the control specimen at the age of 90 days. Also, incorporating 60 wt.% of powdered slag gave rise to the optimum mix plan in terms of freeze-thaw resistance such that a negligible strength degradation was experienced after 300 cycles. In addition, the optimal moisture content of the proposed RCC mixtures was measured to be in the range of 5 to 6.56%. Furthermore, the partial addition of granulated slag was found to be more advantageous than using entirely natural sand in the improvement of the mechanical and durability characteristics of all mixture plans.

• International Journal of Concrete Structures and Materials
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• 제18권1E호
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• pp.63-70
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• 2006

This study tested the alkali-silica reactivity of various types of crushed stones, following the specifications of ASTM C 227 and C 1260, and the results obtained from the tests were compared. This study also analyzed the effects of particle size and grading of reactive aggregate based on the expansion of mortar-bar due to an alkali-silica. The effect of mineral admixtures to reduce the detrimental expansion caused by the alkali-silica reaction was investigated based on the method specified by ASTM C 1260. The mineral admixtures used in this study were fly ash, silica fume, metakaolin and ground granulated blast furnace slag. The replacement ratios of 0, 5, 10, 15, 25 and 35% were uniformly applied to all the mineral admixtures, and the replacement ratios of 45 and 55% were additionally applied for the admixtures that could sustain the workability at these ratios. The results indicate that replacement ratios of 25% for fly ash, 10% for silica fume, 25% for metakaolin and 35% for ground granulated blast furnace slag were the most effective in reducing the expansion due to the alkali-silica reaction under the experimental conditions of this study.

• Structural Engineering and Mechanics
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• 제51권1호
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• pp.1-13
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• 2014

This paper reports an experimental study into the rheological behaviour of self consolidating concrete (SCC). The investigation aimed at quantifying the impact of the varying amounts of mineral admixtures on the rheology of SCC containing natural sand. Apart from the ordinary Portland cement (OPC), the cementitious materials such as fly ash (FA), ground granulated blast furnace slag (GGBS) and micro-silica (MS) in conjunction with the mineral admixtures were used in different percentages keeping the mix paste volume and flow of concrete constant at higher atmospheric tempterature ($30^{\circ}$ to $40^{\circ}C$). The rheological properties of SCC were investigated using an ICAR rheometer with a four-blade vane. The rheological properties of self-consolidating concrete (SCC) containing different mineral admixtures (MA) were investigated using an ICAR rheometer. The mineral admixtures were fly ash (FA), ground granulated blast furnace slag (GGBS), and micro silica (MS). The results obtained using traditional workability results are compared with those obtained using ICAR rheometer. The instrument ICAR (International Center for Aggregate Research) rheometer employed in the present study for evaluating the rhelogical behaviour of the SCC is found to detect systematic changes in workability, cementitious materials, successfully. It can be concluded that the rheology and the slump flow tests can be concurrently used for predicting the flow behaviours of SCC made with different cementitious materials.

• 한국구조물진단유지관리공학회 논문집
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• 제7권1호
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• pp.139-145
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• 2003

Ternary blended concrete, which contains both fly ash and granulated blast furnace slag, has an initial cost effective and is environment friendly. Furthermore, it has a lot of technical advantages such as the improvement of long term compressive strength, high workability, and the reduction of hydration heat. However, as the use and study on the performance of ternary blended concrete is limited, it is worthwhile studying the actual performance of this technology. This study examined the durability performance of ternary blended concrete, compared to binary blended concrete and ordinary portland concrete. It led to the conclusion that ternary blended concrete is very suitable for submerged members under marine environment. However, it should be noticed that ternary blended concrete becomes weak on carbonation, when it is situated on combined deterioration environment of carbonation and chloride. Therefore, the curing duration of ternary blended concrete should be prolonged in order to enhance the resistance of carbonation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.34-35
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• 2015

The purpose of this study is to investigate the compressive strength property of concrete with Ground granulated blast furnace slag(GBFS) using wash water from recycled aggregate. When GBFS is reacted with water, it doesn't happen to hydraulic reaction but GBFS becomes latent hydraulic property in alkaline environment. For this reason, if it is possible to use wash water from recycled coarse aggregate as mixture water, GBFS have the advantage of early strength due to effect of activation. We investigated the compressive strength properties of GBFS concrete using wash water from recycled aggregate. According to the experimentation result, ICP-OES showed wash water from recycled coarse aggregate has a high alkali value of pH of 12. Also, compressive strength in early age using wash water can be improved as an activation.

• Computers and Concrete
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• 제31권4호
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• pp.327-335
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• 2023

The most popular building material, concrete, is intrinsically linked to the advancement of humanity. Due to the ever-increasing complexity of cementitious systems, concrete formulation for desired qualities remains a difficult undertaking despite conceptual and methodological advancement in the field of concrete science. Recognising the significant pollution caused by the traditional cement industry, construction of civil engineering structures has been carried out successfully using Geopolymer Concrete (GPC), also known as High Performance Concrete (HPC). These are concretes formed by the reaction of inorganic materials with a high content of Silicon and Aluminium (Pozzolans) with alkalis to achieve cementitious properties. These supplementary cementitious materials include Ground Granulated Blast Furnace Slag (GGBFS), a waste material generated in the steel manufacturing industry; Fly Ash, which is a fine waste product produced by coal-fired power stations and Silica Fume, a by-product of producing silicon metal or ferrosilicon alloys. This result demonstrated that GPC/HPC can be utilised as a substitute for traditional Portland cement-based concrete, resulting in improvements in concrete properties in addition to environmental and economic benefits. This study explores utilising experimental data to train artificial neural networks, which are then used to determine the effect of supplementary cementitious material replacement, namely fly ash, Ground Granulated Blast Furnace Slag (GGBFS) and silica fume, on the compressive strength, tensile strength, and modulus of elasticity of concrete and to predict these values accordingly.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.30-35
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• 1998

This study was carried out to investigate quantitatively the relationship between the water binder ratio and the concrete strength using finely ground granulated furnace blast slag. In the experiment, the compressive strength and elastic modulus of concrete which slag contents are 0%, 10%, 20% and 30% at 7days and 28days age. As a result, the compressive strength have a high correlation with slag contents and water binder ratio. Thus, it is possible to calculate the water binder ratio using compressive strength of concrete contented with slag.

• International Journal of Concrete Structures and Materials
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• 제8권1호
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• pp.61-68
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• 2014

This paper reports the physical properties and hydration products of slag cement that was prepared by activating ground granulated blast furnace slag with commercial lime and plaster of Paris (POP) as activators. The consistency, setting times and soundness of various mixes of slag-lime-POP is reported. The hydration products and formation of bonds in the paste during setting were studied with the help of SEM, FTIR and XRD tests and the same are correlated to the hydration process. The setting times of the mixes are found to be lower than that of the value prescribed for ordinary Portland cement (OPC). Borax is used as a setting retarder and a borax content of 0.4 % by mass gives setting times that are normally prescribed for OPC. In the early stages of setting C-A-S-H gels are found in this cementing material instead of C-S-H gel, as generally observed in the OPC.

• 한국건축시공학회지
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• 제11권4호
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• pp.345-352
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• 2011

연구의 목적은 반응성 골재를 함유한 알칼리 활성화 고로슬래그 미분말의 알칼리-골재반응으로 인한 팽창을 조사하기 위한 것이다. 또한 이 연구는 현재 존재하고 있는 반응성 골재와 알칼리 재료들의 거동과 관련하여 특별히 관여 되어 지고 있다. 실험 방법은 EDS, SEM을 통하여 알칼리-실리카 반응 생성물의 구성이나 미세구조를 관찰하였으며 알칼리-실리카 반응에 의한 모르터 바의 팽창정도를 측정하였다. 실험 결과에 따르면 알칼리-활성화된 모르터는 알칼리 실리카 반응 때문에 팽창이 되었지만 14일 재령에서 0.1%의 팽창률을 나타내어 알칼리-실리카반응에 대하여 안전한 것으로 나타났다. 그리고 촉진 실험 후 SEM과 BEM분석한 결과 골재 주변과 시멘트 페이스트에 알칼리-실리카 겔 및 띠 모양의 생성물이 나타난 것을 볼 수 있었다. EDX에 따르면 반응생성물이 알칼리 활성화 고로슬래그를 사용하였을 경우 현격히 감소한 것을 볼 수 있다. 추가적으로 광물학적 혼화재료의 대체 재료로써 콘크리트 내구성의 특성을 보증하기 위하여 알칼리 활성화 고로슬래그의 품질을 향상시키는 연구가 필요하다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.473-476
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• 2006

As a part of efforts to obtain high quality and economical efficiency of concrete, blast-furnace slag has been utilized by means of cement replacement. Therefore superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained with utilization by cement replacement. But the studies on the blast-furnace slag are not systematic and reasonable. So, it was planed that basic data in regard to technique of manufacturing and economic improvement of concrete is showed with experimental comparison and investigation of Fluidity and engineering properties of concrete utilizing blast-furnace, industry by-product, as cement replacement in this study.