• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.117-124
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• 2003

Reinforced concrete structures under sever conditions such as marine structures, bridges and structures constructed with aggregates(dredged from sea), can be deteriorated from corrosion of the reinforcing bars. The purpose of this study is to evaluate the anti-corrosive performance of coated steel using polymer cement slurry. Polymer cement slurry with various polymer dispersions and corrosion inhibiting agent were coated to the surface of bars, and tested for accelerated corrosion tests. Tests include immersion in NaCl 10% solution, chloride ion spray, autoclave cure, autoclave cure after carbonation, penetration of NaCl 10 % solution, carbonation after penetration of NaCl 10% solution. Test results, show that the anti-corrosive performace is considerably improved by using polymer cement slurry at surface of steel. And this trend is marked by adding of corrosion inhibiting agent. This difference of the anti-corrosive properties is hardly recognized according to types of polymer dispersions. The coated steel using polymer cement slurry will be improved to a great extent compared to those of plain steel when increasing content of chloride ion in cement concrete.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.71-77
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• 2009

In a range of forms, such as latex, water-soluble polymer, liquid resin, and monomer, polymer dispersions have been widely used in the construction industry as cement modifiers because of their excellent properties, such as acid-resistance, water-proofness, and good ductility in mortar and concrete. Polymer cement slurry (polymer-modified slurry) is made of cement and polymer dispersions, with a high polymer-cement ratio of 50% or more. The purpose of this study is to evaluate the water permeability and drying shrinkage of polymer cement mortar (polymer-modified mortar) and cement concrete coated by polymer cement slurry. The polymer cement mortar and cement concrete are prepared with various polymer types, polymer-cement ratios and curing methods, and are tested for water permeability, drying shrinkage and strength. The test results showed thatthe weight of permeable water of polymer cement mortar decreases with an increase in the polymer-cement ratio, reaching a minimum at the polymer-cement ratio of 20%. In particular, the weight of permeable water of St/BA-modified mortar with a polymer-cement ratio of 20% coated with St/BA-modified slurry is about 1/55 that of unmodified mortar. The EVA- and St/BA-modified slurries coated on cement concrete have about 4 or 5 times higher drying shrinkage compared to cement concrete. The strength of polymer cement mortars tends to increase with a higher polymer-cement ratio, and is considerably higher than that of unmodified mortar. It is thus concluded that polymer cement mortars coated by polymer cement slurry are effective for industrial application, and have superior properties such as waterproofness and strengths, compared with conventional cement mortar.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.635-642
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• 2008

In recent years, epoxy-coated reinforcing bars have been widely used in order to prevent the corrosion of ordinary reinforcing bar. However, they have a bad balance between performance and cost. Especially, they have a brittleness properties, low bond strength to cement concrete and no good bend-ability in the field. The purpose of this study is to evaluate the tensile properties and adhesion of hybrid-type anti-corrosion polymer cement slurry (PCS). PCSs are prepared with four types polymer dispersions using fly ash and silica fume, and tested for proper coating thickness, tensile properties, adhesion to steel plate and bend-ability. From the test results, the viscosity of PCS is effected by polymer dispersion types, and is a little decreased by using fly ash. The coating thickness of PCS has a proper thickness at polymer-binder ratio of 100%. It is apparent that the coating thickness has various values according to viscosity of PCS, water-binder ratio and polymer-binder rato. PCS has a good various anticorrosion properties and physical properties such as tensile strength, adhesion and bend-ability. It is also recommended that proper coating thickness to reinforcing bar is in the ranges of 150 to $250{\mu}m$ for bond strength, adhesion and bend-ability. It is also expected that the coated reinforcing bar using PCS is widely used instead of epoxy coated reinforcing bar in the industrial field.

• Geotechnical Engineering
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• v.13 no.2
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• pp.9-16
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• 1997

Cut-off methods of controlling leachate migration from waste landfills and contaminated sites are studied. Permeability and chemical compatibility tests are prrforlned on slurry wall materials including soil-bentonite, cement-bentonite, cement / fly ash-bentonite, plastic concrete. Hydraulic conductivity of soil-bentonite mixture is the lowest of these four bacuill materials. The leachate from municipal solid waste has little influence on the permeability of the backfill materials. The bentonite slurry becomes flocculated and aggregated when exposed to the leachate. The results of the permeability test showed that the hydraulic conductivities of the backfill materials are in the order soil-beiltonite, Plastic concrete, cement-bentonite. And the result c: the compatibility test showed increase in permeability due to the effects of leachate. Thus, in designing the slurry wall it is essential to check the behaviour of the bentonite slurry and backfill materials on the compatibility with the contaminants.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.703-708
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• 2006

The slurry infiltrated fiber concrete(SIFCON) is recognized as one of the most promising new construction materials. Compressive and direct tensile tests are performed to investigate the mechanical property of SIFCON. Hooked-end steel fibers are used in the mix with fiber volume fraction varied from 4% to 10%. The water/cement ratio is kept constant at 0.4. The amount of silica fume added is 10% by weight of cement and 0.5% of water reducing agent is added to improve the workability of the slurry. The test results in this study show that the compressive strength of SIFCON is about 1.59 to 2.68 times in comparison with the cement paste. Tensile strength is showed the enhancement of about 2.51 to 8.77 times. It is also observed that the toughness and ductility of SIFCON are increased significantly with the increasing in fiber volume fraction.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.245-251
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• 2021

This study was to investigate the effect of the new surface treatment method of zirconia on the shear bond strength with resin cement. The zirconia specimens were classified according to the surface treatment. CON: non-treatment, HF: 10 minutes exposure to 9% HF, ZS15: Apply 15% ZrO2 slurry, ZS30: Apply 30% ZrO2 slurry, ZS50: Apply 50% ZrO2 slurry. The resin cement was layered on the surface treated zirconia, and the shear bond strength between the zirconia and the resin cement was measured after thermo-cycling. The statistical methods for shear bond strength were Kruskal-Wallis test, Mann-Whitney U test, and Bonferroni correction(α=.05/10=.005). ZS15, ZS30, and ZS50 groups treated with zirconia slurry showed higher shear bond strength than CON and HF groups(p<.05/10=.005). Within the limits of this study, the surface treatment using zirconia slurry increased the shear bond strength with resin cement. The new surface treatment method complements and improves the limitations of the adhesion of zirconia, so that various clinical applications of zirconia can be expected.

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.346-353
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• 2001

This research investigates the mixture proportioning of waste newsprint paper fiber for thin-cement product. Waste newsprint paper fibers obtained through shredded mechanically by a dry process. Waste newsprint paper fiber reinforced cement composites was manufacted by slurry-dewatering method. The waste newsprint paper fiber reinforcement conditions (fiber mass fraction, level of substitution of virgin fibers, level of fiber beating) and processing variables (pressed, unpressed) are optimized through experimental studies and statistical analyses based on factorial design of experiments and analyses of variance. The optimized recycled waste newsprint paper fiber reinforced cement composites were technically evaluated. The results are shown to possess acceptable properties and strong potentials of the recycling of waste newsprint paper of the reinforcement of thin-cement products.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.335.1-335
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• 2001

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.633-640
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• 2015

Polymer cement slurry (PCS) is made from organic polymer dispersion and cement has good adhesion to steel, waterproofness and acid resistance due to being of polymer films formed in cement slurry. The purpose of this study is to evaluate the bond strength of coated rebar by polymer cement slurry made of EVA and ultra high-early strength cement. The test pieces are prepared with EVA polymer dispersion and ultra high-early strength cement having four types of polymer-cement ratios, four types of coating thicknesses and four curing ages, and tested for the bond strength test. From the test results, in general, bond strength of PCS-coated rebar is better than that of uncoated rebar and epoxy-coated rebar. It is also high bond strength at curing ages of 7-day, and coating thicknesses of $75{\mu}m$ and $100{\mu}m$. The maximum bond strength of PCS-coated rebar with ultra high-early strength cement and EVA at polymer-cement ratio of 80%, and coating thickness of $100{\mu}m$ is about 1.32 and 1.38 times respectively, the strength of uncoated rebar and epoxy-coated rebar. It is apparent that the curing age, coating thickness, type of polymer and cement are very important factors to improve the bond strength of PCS-coated rebar to cement concrete. We can have basic information that PCS-coated rebar with polymer-cement ratio of 80% or 100% and coating thickness of $100{\mu}m$ at curing age of 1-day can replace epoxy-coated rebar.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.167-174
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• 2017

This research investigated the mechanical performance of slurry infiltrated high performance fiber reinforced cementitious composite (SI-HPFRCC) with high volume blast furnace slag powder. Hooked-end steel fibers (volume fraction of 6.4%) were used for the fabrication of SI-HPFRCC. A series of mechanical performance test was conducted including strength and toughness of SI-HPFRCC in compressive and flexural mode at four different ages. Compressive and flexural strength tests of the slurry matrix at the same ages were also conducted in order to evaluate fiber reinforcing effect on the mechanical performance. The flexural response of SI-HPFRCC shows an increasing brittleness with age. The compressive response also shows an increasing brittleness with age but the degree of brittleness is much lower than the flexural case. In terms of strength, SI-HPFRCC shows about 140~190% of compressive strength improvement and 440~500% flexural strength improvement comparing to the slurry matrix.