• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
• /
• pp.251-257
• /
• 1998

Concrete is considered to be one of the excellent and versatile shielding material and is widely used for the radiation shielding materials. This paper aims to study mechanical properties of concrete by using normal cement, natural and heavyweight aggregate and their radiation shielding effects through radiation transmission tests.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
• /
• pp.233-236
• /
• 2003

This study is intended to investigate the resistance of frost damage of concrete for planting, which recycled aggregate is used, by freezing in air and thawing in water. According to the results, if AE agent of 0.005% is mixed in making concrete for planting, it is thought that the resistance of frost damage is guaranteed in winter because concrete for planting is not under severe freezing and thawing function, but under natural weather action.

• 한국건설순환자원학회논문집
• /
• 제12권2호
• /
• pp.188-195
• /
• 2024

최근 환경문제와 골재난의 해결방안으로 건설폐기물을 재활용한 순환골재의 사용이 주목받고 있다. 순환골재의 재활용을 촉진하기 위해 마련된 여러 다양한 방안에도 불구하고, 순환골재는(특히 순환잔골재) 일반골재에 비하여 품질이 떨어지기 때문에, 구조체용 골재로서의 사용은 제한되고 있어, 순환골재 품질 향상에 관한 연구가 시급하다. 본 연구에서는 순환잔골재 품질 향상을 위해 1시간이라는 짧은 시간 동안 다양한 농도의 아크릴 수지 수용액에 순환잔골재의 침지를 진행하였고, 침지가 종료된 순환잔골재의 흡수율 및 진밀도 측정을 통해 적정 침지농도를 선정한 후, 모르타르 시험체를 제작하고 이의 역학적 성능을 평가하여 순환잔골재 재활용을 촉진시키는 처리방법을 제시하고자 하였다. 실험 결과에 따르면, 아크릴 수지 농도가 높아질수록 순환잔골재의 흡수율과 진밀도는 감소하였으며, 흡수율의 경우 아크릴 수지 농도 6~8 % 수준에서 가장 낮게 나타났으나, 아크릴 수지에 침지시킨 순환잔골재 모르타르의 압축강도는 이보다 낮은 농도인 4 %에서 가장 높게 나타나, 높은 농도의 아크릴 수지 사용이 모르타르 압축강도를 오히려 저하시킬 수 있음을 확인하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
• /
• pp.359-362
• /
• 2000

From a practical perspective, sustainable development requires the optimization of current natural resources and the minimization of derived wastes. A major concern with respect to sustainable infrastructure development is the continued depletion of easily-available natural resources and environmental matters are more serious, the concerned about waste materials which are inevitably produced in the manufacturing of the product is getting worse. These wastes must be handled and properly disposed, and many times, although this waste may be environmentally inert, it has been discarded in landfills. But current disposal methods of these by-products create not only a loss of profit for the power industry, but also environmental concerns the breed negative public opinion. therefore, this study evaluates the ECO artificial aggregate and bricks were designed and tested for the end use of fly ash.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.723-726
• /
• 2005

As the importance of recycled materials is being emphasized more in the Korean construction market, the production quality has been improved to a significantly high level. Compared to the high quality, however, there are used very limitedly. Among recycled construction materials, recycled aggregates produced through the retreatment of waste concrete are drawing attention because of lack of natural aggregate and heightened consciousness of resource saving and environmental protection and, as a consequence, they are close to natural aggregates in terms of production technology and quality. Despite the high quality and productivity, however,. the utilization of recycled aggregates is very low. Thus, in order to maximize the utility of recycled aggregates, the present study examined the usability of recycled aggregates using both recycled coarse aggregates and recycled fine aggregates together and derived optimal quantity and mixture ratio in the combined use of the two types of recycled aggregate.

• Advances in concrete construction
• /
• 제5권5호
• /
• pp.437-450
• /
• 2017

The present work investigates about the development of a novel construction material by utilizing Granulated Blast Furnace Slag (GBS), an industrial waste product, as substitution of natural fine aggregates. For this, experimental work has been carried out to determine the influence of GBS on the properties of concrete such as compressive strength (CS), modulus of elasticity, ultrasonic pulse velocity (UPV), chloride penetration, water absorption (WA) volume of voids (VV) and density. Concrete mixes of water/cement (w/c) ratios 0.45 and 0.5, and incorporating 20%, 40% and 60% of GBS as partial replacement of natural fine aggregate (sand) are designed for this study. The results of the experimental investigation depict that CS of concrete mixes increases with the increasing percentages of GBS. Moreover, the decrease in chloride penetration, WA and VV, and improvement in the modulus of elasticity, UPV, density of concrete is reported with the increasing percentage of GBS in concrete.

• Advances in concrete construction
• /
• 제6권6호
• /
• pp.611-629
• /
• 2018

The objective of present study is to investigate the effect of granulated blast furnace slag (GBS) as partial substitution of natural sand on behaviour of cement mortar. For this, the methods of factorial design with water cement (w/c) ratio and incorporation percentages of GBS as replacement of natural fine aggregate i.e., GBS(%) as factors are followed. The levels of factor w/c ratio are fixed at 0.4, 0.45, and 0.5 and the levels of factor GBS(%) are kept fixed as 0%, 20%, 40%, 60%, 80% and 100%. The compressive strength (CS) of mortar after 3, 7, 14, 28, 56 and 90 days, and water absorption (WA) are chosen as responses of the study. Analysis of variance (ANOVA) of experimental results has been carried out and those are illustrated by ANOVA tables, main effect and interaction plots. The results of study depict that the selected factors have substantial influence on the strength and WA of mortar. However, the interaction of factors has no substantial impact on CS and WA of mixes.

• 한국항만학회지
• /
• 제9권1호
• /
• pp.65-72
• /
• 1995

This study is being done for the purpose to achieve a stable demand and supply of materials for long term. The author investigated condition of suitable mixer design method for concrete, an individual value and a character of dynamics as a supplement material by drying up the natural aggregate, and a possible practicalization plan to reduce defects to the minimum. As a result of this study, it can be acquired a good quality of concrete by the use of the natural sand (Nak Dong river sand) and the crushed sand with suitable mixing ratio. The fineness modulus (F.M) of mixing aggregate is $2.7\pm1$ at this time and this is good for workbility and plasticity of concrete.

• 콘크리트학회논문집
• /
• 제21권3호
• /
• pp.367-375
• /
• 2009

최근 골재 수급불균형 문제 및 천연자원 고갈에 관한 사회적 관심이 집중되는 가운데, 종래 철강공정에서 부산물로 발생하는 슬래그 중 전기로 산화슬래그는 그 물리적 특성이 일반 골재와 유사한 특성이 있어 콘크리트용 골재로서 활용가능성이 높게 평가되나 슬래그 중 함유되어 있는 free-CaO에 의한 표면결함을 야기하는 문제를 내재하고 있다. 본 연구는 이러한 전기로 산화슬래그 골재의 화학적 안정성 확보방안을 도출하고 이를 통해 안정화된 슬래그 골재를 용도별 콘크리트용 잔골재로 활용하여 콘크리트의 역학적 성능 및 내구성능을 실험적으로 평가하여 전기로 산화슬래그 잔골재의 활용방안을 제시하는데 그 목적이 있다. 본 연구결과, 전기로 산화슬래그의 골재입경 조정, 소정 기간동안의 자연 에이징 처리에 의해 팝아웃 등의 표면결함을 대폭 저감할 수 있는 것으로 나타났으며, 콘크리트 용도별 대체율에 따른 역학적 성능 및 내구성능은 일반 골재와 비교하여 동등 또는 동등이상의 성능을 발현하는 것으로 평가되었다. 향후 전기로 산화슬래그 잔골재 활용시에는 콘크리트의 미관저해 현상이 나타나지 않도록 충분한 사전 에이징 또는, 가공처리 등 안정성 확보를 위한 품질관리가 반드시 선행되어야 할 것이다. 또한, 철강부산물의 친환경적인 자원순환 시스템을 확립하기 위해서는 전기로 산화슬래그 골재에 대한 품질관리 지표 구축과 더불어 다양한 용도개발이 이루어져야 하며 각종 공학적 특성 및 내구성에 관한 지속적인 연구개발이 이루어져야 할 것이다.

• Computers and Concrete
• /
• 제26권4호
• /
• pp.327-342
• /
• 2020

The objective of this study is to manufacture environmentally-friendly synthetic lightweight aggregates that may be used in the structural lightweight concrete production. The cold-bonding pelletization process has been used in the agglomeration of the pozzolanic materials to achieve these synthetic lightweight aggregates. In this context, it was aimed to recycle the waste fly ash by employing it in the manufacturing process as the major cementitious component. According to the well-known facts reported in the literature, it is stated that the main disadvantage of the synthetic lightweight aggregate produced by applying the cold-bonding pelletization technique to the pozzolanic materials is that it has a lower strength in comparison with the natural aggregate. Therefore, in this study, the metakaolin made of high purity kaolin and calcined kaolin obtained from impure kaolin have been employed at particular contents in the synthetic lightweight aggregate manufacturing as a cementitious material to enhance the particle crushing strength. Additionally, to propose a curing condition for practical attempts, different curing conditions were designated and their influences on the characteristics of the synthetic lightweight aggregates were investigated. Three substantial features of the aggregates, specific gravity, water absorption capacity, and particle crushing strength, were measured at the end of 28-day adopted curing conditions. Observed that the incorporation of thermally treated kaolin significantly influenced the crushing strength and water absorption of the aggregates. The statistical evaluation indicated that the investigated properties of the synthetic lightweight aggregate were affected by the thermally treated kaolin content more than the kaoline type and curing regime. Utilizing the thermally treated kaolin in the synthetic aggregate manufacturing lead to a more than 40% increase in the crushing strength of the pellets in all curing regimes. Moreover, two numerical formulations having high estimation capacity have been developed to predict the crushing strength of such types of aggregates by using soft-computing techniques: gene expression programming and artificial neural networks. The R-squared values, indicating the estimation performance of the models, of approximately 0.97 and 0.98 were achieved for the numerical formulations generated by using gene expression programming and artificial neural networks techniques, respectively.