• International Journal of Concrete Structures and Materials
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• v.8 no.1
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• pp.69-81
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• 2014

In this study, portland cement (PC) has been partially replaced with a Class F fly ash (FA) at level of 70 % to produce high-volume FA (HVFA) concrete (F70). F70 was modified by replacing FA at levels of 10 and 20 % with silica fume (SF) and ground granulated blast-furnace slag (GGBS) and their equally combinations. All HVFA concrete types were compared to PC concrete. After curing for 7, 28, 90 and 180 days the specimens were tested in compression and abrasion. The various decomposition phases formed were identified using X-ray diffraction. The morphology of the formed hydrates was studied using scanning electron microscopy. The results indicated higher abrasion resistance of HVFA concrete blended with either SF or equally combinations of SF and GGBS, whilst lower abrasion resistance was noted in HVFA blended with GGBS.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.53-56
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• 2006

To develop more durable concrete deck, performance characteristic test of HPC(High Performance Concrete) mixtures was carried out. The parameters used in this project were ; the mineral admixture details were 4 types such as ordinary portland cement(OPC), 20% fly ash (FA), 20% fly ash and 4% silica fume(FS), and 40% ground granulated blast-furnace slag(BS). Their design compressive strengths were 27MPa and 35MPa respectively. The results showed the compressive strength of concrete did not much affect the durability of concrete. HPC with blast-furnace slag(BS) showed the good durability but was prone to crack. HPC with fly ash(FA) or with fly ash and silica fume(FS) had the good durability and crack resistance.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.435-436
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• 2009

The objective of this study was to develop the high-durable concrete which is mixed silica fume and fly ash in post-tensioned concrete pavement. Test results show that early-age compressive strength was increased with addition of silica fume. Water-permeability was improved significantly comparing with standard concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.308-314
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• 1997

Shrinkage and creep are the fundamental properties of concrete. These long term deformations can be seen as bothersome(increased deflection) or can be seen as reduction of compressive stress of prestressed concrete. Steel fibers advance the mechanical properties of concrete:tensile strength, ductility, flexural strength, fracture toughness, and post-cracking resistance, etc...Silica fume is pozzolanic material which combines with hydrated lime to generate silicate materials which increase the compressive strength and reduce somewhat the creep of concrete. This paper is the result of the long-term deformation by silica fume and steel fibers with varying percentages.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.157-162
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• 1990

Recently, the multistory building construction of reinforced concrete has increased year by year, trended to be high rise in the view of effective land use planning, costing down of building construction and residential conditions. For this urgent need in construction industry, research and development of workability and engineering properties of high strength concrete has been closed up as one of the big world wide problems to be solved reasonably. It is aim of this study to provide the fundamental data the workability and engineering properties of steel-fiber reinforced high strength concrete containing silica-fume and fly-ash comparing with plain concrete for the practical use and research data accumulation in the side of development of new material in the building construction.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.644-647
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• 2004

Modulus of rupture (MOR) and flexural toughness in hybrid fiber reinforced cement pastes mixed with micro-fiber (carbon fiber) and macro-fiber (steel fiber) and replaced with silica fume according to the fixed ratio were researched. Reinforcing efficiency in specimens were estimated by two factors, such as strengthening factor $(F_s)$ and toughening factor $(F_t)$, which were calculated from the analysis of variance (ANOVA) of the response values, such as MOR and absorbtion energy $(W_0)$. According to the experimental design by the fractional orthogonal array, nine hybrid fibrous reinforced paste series and one non-reinforced control paste were manufactured. Specimens of each series were tested by the INSTRON Inc. 8502(model) equipment in three-points bending and then measured the load-deflection response relationships. Considerable strengthening of cement pastes resulted in' the case of other factors without carbon fiber and toughening of cement pastes about all factors showed high. Based on the significance of factors related to response values from ANOVA, following assessments were available; $F_s$ or MOR: silica fume $\gg$ steel fiber $\gg$ carbon fiber; $F_t\;or\;W_0$: steel fiber > carbon fiber > silica fume. Optimized composition condition was estimated by steel fiber of $1.5\%$, carbon fiber of $0.5\%$ and silica fume $7.5\%$ in side of strengthening and steel fiber of $1.5\%$, carbon fiber of $0.75\%$ and silica fume $7.5\%$ in side of toughening.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.125-133
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• 1998

In this study, an experiment in the field was performed to analyze the influence of steel fiber and silica fume on the rebound ratios of shotcrete. The experimental parameters which are the reinforcing methods(steel fiber, wire mesh), steel fiber contents(0.0%, 0.5%. 0.75%, 1.0%), silica fume contents(0.0%, 10.0%), and the three placing parts(side wall, shoulder, crown) were chosun. According to the results for the side wall in this test, the larger the fiber contents are in case of steel fiber reinforced shotcrete, the less the rebound ratios are within the range of 20~35%, compared to the wire mesh reinforced shotcrte. And also, the reduced rebound ratios were vary larger in using steel fiber reinforced shotcrete with silica fume content of 10%, and these results are true of the shoulder and the crown, respectively. In addition, the four-stage phenomenon for the rebound of the SFRS were estimated in the view of the co-action between steel fiber and coarse aggregate based upon the existing two-stage analysis method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.55-56
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• 2011

This paper is to compare and analyze the properties of ultra high strength concrete depending on the use of SF aiming for applicability of superplasticizer containing CASB as a functional agent for strength improvement. As experimental results, in case superplasticizer containing CASB is used, regardless of W/B, settiing time was more accelerated than N, and both compressive strength and tensile strength showed an increase in their strength minutely.

• Computers and Concrete
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• v.18 no.3
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• pp.367-388
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• 2016

In this paper, a simple practical method is introduced in which a simple weight measurement of concrete and finite element numerical analysis are used to determine the moisture transfer coefficient of concrete with a satisfactory accuracy. Six concrete mixtures with different water-to-cementitious material (w/cm) ratios and two pozzolanic materials including silica fume and zeolite were examined to validate the proposed method. The comparison between the distribution of the moisture content obtained from the model and the one from the experimental data during both the wetting and drying process properly validated the performance of the method.With the proposed method, it was also shown that the concrete moisture transfer coefficient considerably depends on the pore water saturation degree. The use of pozzolanic materials and also lowering w/cm ratio increased the moisture transfer coefficient during the initial sorption, and then, it significantly decreased with an increase in the water saturation degree.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.433-436
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• 2006

The trends of research for concrete in recent days are the high performance, high flow, ultra high strength and high durability. These are being researched with a construction company and a materials company. Anyone have to use the good quality sand, gravel, high quality chemical compound and silica fume for ultra high strength concrete as yet. This paper was researched with the domestic materials, not use the high price silica fume for the development 100MPa ultra high strength concrete with laboratory tests and mock-up test.