• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.561-566
• /
• 2002

Recently, high quality exposed concrete is needed to achieve high quality surface for outer wall of the building. In this study, to solve above characteristic of the exposed concrete we selected self compacting concrete(SCC) and compared with normal concrete. So, we developed the SCC mix design and performed the semi mock-up test. Through this result, we performed the pilot test and mock-up test to check surface of outer wall and to measure formwork pressure As a result because SCC is better than normal concrete with respect to flowability and seggregation resistance SCC is suit to a exposed concrete needed high quality surface for outer wall of the building.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
• /
• pp.85-88
• /
• 2006

This study describes the optimum mix proportion of the high strength and self-compacting concrete placed in main structures of LNG above tank. This concrete requires high strength level about $60{\sim}80MPa$, low hydration heat, balance between workability and consistency without vibrating in the actual work. For this purpose, low heat portland cement and fly ash are selected and design factors including water-binder ratio, replacement ratio of fly ash are tested. As experimental results, low heat portland cement shows lower the confined water ratio than another cement type and the optimum replacement ratio of fly ash in order to improve properties of the binder-paste shows 10% by cement weight considering test results of the confined water ratio$({\beta}p)$. Also, flowability of the high strength and self-compacting concrete by using fly ash about $10{\sim}20%$ is improved. The replacement ratio of fly ash 10% and water-binder ratio $25{\sim}27%$ are suitable to the design strength 80MPa and cost, In case of the design strength 60MPa, the replacement ratio of fly ash and water-binder ratio show 20% and $25{\sim}30%$ separately. Based on the results of this study, the optimum mix proportions of the high strength and self-compacting concrete will be applied to the construction of LNG above tank as a new type.

• Computers and Concrete
• /
• 제19권2호
• /
• pp.203-210
• /
• 2017

The purpose of this paper is to evaluate the settlement of lightweight coarse aggregate of self-compacting lightweight concrete (SCLC) after placement of concrete on its final position. To investigate this issue, sixteen samples of concrete mixes were made. The water to cementitious materials ratios of the mixes were 0.35 and 0.4. In addition to the workability tests of self-compacting concrete (SCC) such as slump flow, V-funnel and L-box tests, a laboratory experiment was made to examine the segregation of lightweight coarse aggregate in concrete. Because of the difficulties of this test, the image processing technique of MATLAB software was used to check the segregation above too. Moreover, the fuzzy logic technique of MATLAB software was utilized to improve the clarity of the borders between the coarse aggregate and the paste of the mixtures. At the end, the results of segregation tests and software analyses are given and the accuracy of the software analyses is evaluated. It is worth noting that the minimum and maximum differences between the results of laboratory tests and software analyses were 1.2% and 9.19% respectively. It means, the results of image processing technique looks exact enough for estimating the segregation of lightweight coarse aggregate in SCLC.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.573-578
• /
• 2002

We carried out the feasibility study of super early self compacting concrete having the characteristics of 1 day demoulding without steam curing, high flowable concrete with self compacting, high strength and high durability etc. Here, We test and selected by several methods using high early cement with and without admixtures for the condition of super early strength self compacting concrete's manufacture (SSCC). We sucessed to meet at the goal of SSCC with 30∼35N/㎟ in 1 day, without steam curing and with slump flow about 60-65cm and suggest various concrete products to apply the developed SSCC for practical use in factory and in site place

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.555-560
• /
• 2002

The structure of Chosun-ilbo Boopyung factory was desined as exposed concrete. The self compacting concrete(non-vibrating concrete) must be applied to this case because the exposed concrete wall is very thin(200mm) and high(6m), Laboratory tests and semi mock-up test were performed for optimum mix design of the self compacting concrete. As a result, the optimum mixes were observed at the 3-component types(ope, fly-ash, slag powder) that Vp$\geq$0.175, Vw/Vp$\geq$0.95, W=170~175$kgf/m^3$ and B=500~540$kgf/m^3$ Based on this result. we make plan that the pilot productions of batcher plant, the full-scale mock up tests and site application.

• Computers and Concrete
• /
• 제14권4호
• /
• pp.419-444
• /
• 2014

In this study experimental result of a total of eight SCC and FRSCC slabs with the same cross-section were monitored for up to 240 days to measure the time-dependent development of cracking and deformations under service loads are presented. For this purpose, four SCC mixes are considered in the test program. This study aimed to compare SCC and FRSCC experimental results with conventional concrete experimental results. The steel strains within the high moment regions, the concrete surface strains at the tensile steel level, deflection at the mid-span, crack widths and crack spacing were recorded throughout the testing period. Experimental results show that hybrid fibre reinforced SCC slabs demonstrated minimum instantaneous and time-dependent crack widths and steel fibre reinforced SCC slabs presented minimum final deflection.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.979-984
• /
• 2002

The mat foundation of Tower Palace III is designed as a massive structure which has a 3.5m depth. The purpose of this study is to determine the optimum mix design having good workability and to control the actual concrete quality in site. For this purpose, we select the Self Compacting Concrete. Recently, the Self Compacting Concrete has been applied to achieve workability improvement. As the result of actual application, we have finished placing the mass concrete of 8, 000m$^3$ during 14hours with good success and obtain the good quality concrete. All test results are satisfied with our specifications for mat foundation and cut cost as the reduction of placing hours.

• 한국농공학회논문집
• /
• 제46권4호
• /
• pp.57-63
• /
• 2004

This study was performed to evaluate flow properties of polypropylene fiber reinforced high flow concrete. Test results were showed that the slump, slump flow and L-type compacting were decreased with increasing the content of polypropylene fiber. But, the Box-type passing and air content were increased with increasing the content of polypropylene fiber. The slump was $25.5{\sim}27.5cm$, the slump flow was $60{\sim}65cm$, the Box-type passing was $2{\sim}6cm$, the L-type compacting was excellent and air content was $2.7{\sim}3.2cm%$ by the polypropylene fiber content 0.2%, respectively. This concrete can be used for high flow concrete.

• Computers and Concrete
• /
• 제18권1호
• /
• pp.113-137
• /
• 2016

Extensive experimental studies on remarkable mechanical properties Polypropylene Fibre Reinforced Self-compacting Concrete (PFRSCC) have been executed, including different fibre volume fractions of Polypropylene fibers (0.25%, 0.5%, 0.75%, and 1%) and different water to cement ratios (0.21, 0.34, 0.38, and 0.41). The experimental program was carried out by using two hundred and sixteen specimens to obtain the impact resistance and mechanical properties of PFRSCC materials, considering compressive strength, splitting tensile strength, and flexural strength. Statistical and analytical studies have been mainly focused on experimental data to correlate of mechanical properties of PFRSCC materials. Statistical results revealed that compressive, splitting tensile, and flexural strengths as well as impact resistance follow the normal distribution. Moreover, to correlate mechanical properties based on acquired test results, linear and nonlinear equations were developed among mechanical properties and impact resistance of PFRSCC materials.

• International Journal of Concrete Structures and Materials
• /
• 제1권1호
• /
• pp.3-9
• /
• 2007

Fiber-reinforced self-compacting concrete (FRSCC) is a new type of concrete mix that can mitigate two opposing weaknesses: poor workability in fiber-reinforced concrete and cracking resistance in plain SCC concrete. This study focused on early-age cracking of FRSCC due to restrained drying shrinkage, one of the most common causes of cracking. In order to investigate the effect of fiber on shrinkage cracking of FRSCC, ring shrinkage tests were performed for polypropylene and steel fiber-reinforced SCC. In addition, finite element analyses for those specimens were carried out considering drying shrinkage based on moisture diffusion, creep, cracking resistance of concrete, and the effect of fiber. The analysis results were verified via a comparison between the measured and calculated crack width. From the test and analysis results, the effectiveness of fiber with respect to reducing cracking was confirmed and some salient features on the shrinkage cracking of FRSCC were obtained.