• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
• /
• pp.287-290
• /
• 1998

Recently great efforts and investment have been made in order to achieve economical production by applying new methods like minimization of man-power into construction field. Therefore in this study, we have been focused on the development and practical using of semi-high-fluidity concrete with viscosity agent and fly-ash, also we find out the optimum mix proportions to accomplish good quality semi-high-fluidity concrete. The results of this study show that semi-high-fluidity concrete with viscosity agent of 0.03~0.1%(W$\times$%) and the ratio of fly-ash replacement of 10~20% in W/B of 35~45% has better performance than the high-fluidity-concrete.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
• /
• pp.139-140
• /
• 2019

In this study, we considered the influence on segregation resistance at the time of substitution of FA and BS, which are substance admixtures of high fluidity concrete. According to the research results, EIS, which is an index of segregation in high fluidity concrete replacement, showed a low value, and the composition also showed a higher value than OPC. Therefore, it is confirmed that the resistance to segregation at the time of admixture replacement of high fluidity concrete is improved.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.223-224
• /
• 2021

Recently, the demand for high fluidity concrete has been increased due to skyscrapers. However, it has its own limits. First of all, high fluidity concrete has large variation and through trial & error it costs lots of money and time. Neural network model has repetitive learning process which can solve the problem while training the data. Therefore, the purpose of this study is to predict optimum mix design of 40MPa, 60MPa high fluidity concrete by using neural network model and verifying compressive strength by applying real data. As a result, comparing collective data and predicted compressive strength data using MATLAB, 40MPa mix design error rate was 1.2%~1.6% and 60MPa mix design error rate was 2%~3%. Overall 40MPa mix design error rate was less than 60MPa mix design error rate.

• 한국건축시공학회지
• /
• 제22권2호
• /
• pp.125-136
• /
• 2022

본 연구의 목적은 고유동 콘크리트의 활용범위를 증진시키기 위하여 거푸집 정밀도 부족에 따른 고유동 콘크리트의 누출을 방지 혹은 저감하는 것이다. 일반강도 콘크리트에 고유동성이 부여되는 경우 거푸집의 정밀도가 낮으면 거푸집 틈새로 콘크리트 누출이 우려되는바 일반적인 현장에서 유동성이 높은 일반강도 콘크리트의 적용에 지장이 있다. 이에 본 연구는 이전 연구결과에서 얻어진 PVA와 붕사를 사용한 고요변성 부여하는 방법을 이용하여 고유동 콘크리트에 요변성을 부여하여 거푸집의 누출을 저감하고자 연구를 수행하였다. 연구결과를 통해 PVA와 붕사가 고유동 모르타르 조건에서 거푸집 누출 저감에 기여한다는 것을 증명하였다. 이를 통해 고유동 콘크리트의 거푸집 누출량 저감 연구의 시작점이 될 것으로 기대한다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
• /
• pp.63-68
• /
• 1998

The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

• 한국주조공학회지
• /
• 제24권4호
• /
• pp.217-224
• /
• 2004

The effect of casting variable on the fluidity of high silicon, especially hypereutectic, heat-resistant ductile cast iron melt was investigated. When pouring temperature and silicon content were constant, that was increased with carbon content. When the pouring temperature and carbon content were constant, that also increased with the silicon content. Even though these results were thought to be caused by the high heat of fusion evolved during the crystallization of proeutectic graphite nodules, further research seemed to be needed. The fluidity for taller sprue was higher than that for smaller one.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2008년도 추계 학술논문 발표대회
• /
• pp.89-92
• /
• 2008

This research analyzed the basic characteristics of unhardened concrete and the compression strength characteristics of hardened concrete according to liquidity retention agent mix rate change to improve the liquidity fluidity retention performance of high performance concrete, and produced the following results. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, which increased fluidity retention agent mix rate, slump flow decreased, and in the case of slump flow according to the progress time change by the fluidity retention agent mix rates, the more fluidity retention agent mix rate increased, the lower slump flow change rate became. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, fluidity retention agent mix rate increased compared to non-mixture of fluidity retention agent, and the air amount by progress time change by the fluidity retention agent mix rates slightly increased, however target range is still met and unit volume mass is inversely proportional to air amount. Compression strength according to age progress by the fluidity retention agent mix rates was shown to increase slightly with increase in fluidity retention agent mix rate, and yet the difference was not significant.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
• /
• pp.93-98
• /
• 1998

Fluidity retention of concrete used high range water reducing AE agent(HWAE) is varied according to type, dosage amount and dosing method of HWAE. The type and substitution ratio of mineral admixture also have influence on the fluidity retention of concrete using HWAE. For the purpose of improving the fluidity retention in concrete used HWAE, 3 types of HWAE and ground granulated blast furnace slag(SG) are applied in cement-based composites such as cement paste, mortar and concrete respectively. According to using the HWAE of naphthalene sulfonates and SG, the fluidity retention of mortar and concerete is improving the fluidity retention and strength of concrete regardless of type of HWAE.

• 한국주조공학회지
• /
• 제22권3호
• /
• pp.109-113
• /
• 2002

A good fluidity of high strength Al-alloys is required to cast thin wall castings needed to reduce the weight of cast parts. The fluidity, measured as the length to which the metal flows in a standard channel, is affected by many factors, such as the pouring temperature, solidification type of the alloy, the channel thickness, melt head, mold materials and temperature, coating etc. Therefore the experimentally measured fluidity scatters very much and makes it difficult to estimate the fluidity of a melt with a few measurements. The effect of Ti content and grain refinement on the fluidity of high strength aluminum alloy was investigated with a test casting with 8 thin flow channels to reduce the scattering of the fluidity results. The fluidity of Al-4.8%Cu-0.6%Mn Al-6.2%Zn-1.6%Mg-1.0%Cu and well-known commercial aluminum alloy, A356 was tested. Initial content of Ti was varied from 0 to 0.2wt% and Al-5Ti-B master alloy was added for grain refinement. The flow length varied linearly with superheat. By adding Ti and Al-5Ti-B, the fluidity increased. The grain size decreased by adding grain refiner at the same time. The fluidity depended on the degree of grain refinement. The fluidity of the alloy solidifying in mushy type is improved by grain refinement, because grain refinement increases the solid fraction at the time of flow stoppage.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 추계 학술논문 발표대회
• /
• pp.186-187
• /
• 2013

Recently, high fluidity concrete is becoming more prevalent. High fluidity concrete uses admixture or thickener in order to prevent separation of materials due to increased fluidity, and, especially, BS is becoming more use for reduced heat of hydration and improved long-term strength. This study examined the effect of BS on fluidity of cement paste from a rheological viewpoint. As for BS types, materials equivalent to 1 types of KS F 2563 and the cement mass was substituted by 20, 40, 60, 80%.