• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.539-547
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• 2007

The effects of binder and alumina content on the setting time, drying shrinkage, strength, freezing and thawing resistance and water absorption of polymer-modified pastes with alumina powder were examined. As a result the setting time of the polymer-modified pastes with alumina powder tended to delay with increasing binder content. Irrespective of the type of polymer, the drying shrinkage of the polymer-modified pastes with alumina powder tended to decrease with increasing binder content and alumina powder content. Regardless of the type of polymer, the tensile and adhesion strengths of the polymer-modified pastes with alumina powder tended to increase with increasing binder content and alumina powder content. Irrespective of the type of polymer, the durability factors of the polymer-modified pastes with alumina powder tended to increase with increasing alumina content. Irrespective of the type of polymer, the water absorptions of the polymer-modified pastes with alumina powder tended to decrease with increasing binder content and alumina content.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.227-232
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• 2006

This article presents the results of experimental study that investigates the effect of filler and shrinkage reducing agent influencing on the strength properties of MMA-modified polymer paste that was produced to develop the surface-repair and coating materials of the concrete structures. Results show that the flexural and compressive strengths of the polymer paste increased 29 and 27%, respectively, when the aluminum hydroxide completely replaced the calcium carbonate as the filler Furthermore, when the shrinkage reducing agent was used 30%, both strengths decreased about 29% comparing to when the agent was not used. As in the cases of flexural and compressive strengths, the adhesive strength increased as the content of aluminum hydroxide as the filler increased, and it decreased as the content of shrinkage reducing agent increased. The adhesive strength with a dry concrete substrate turned out to be $30{\sim}40%$ higher than that with a wet concrete substrate.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.300-303
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• 2004

In this study, the mixing contents of ceramic powder and of shrinkage-reducing agent (SRA) influencing on the strength properties of MMA-modified polymer paste were examined. Regardless of SRA content, the flexural. the compressive and the adhesive strengths of the MMA-modified polymer paste tended to increase as the mixing content of ceramic powder increased. On the other hand, those strengths of the polymer paste tended to decrease as the mixing content of SRA increased without regard to the paste content. Furthermore. the adhesive strength of MMA-modified polymer paste in a wet condition decreased about $30-40\%$ of that in an air-dry condition without regard to the mixing content of ceramic powder and SRA.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.807-810
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• 2005

In this study, MMA-modified paste of coating material for protecting the concrete structures was developed. The coating material was applied to cement concrete specimens by brush, roller and spray in each of which one, two and three layers to survey, by the cold-hot iterative test, the neutralization test, the chloride ion permeation test and the ante-abrasion test, the affect of painting methods and layers influencing on the durability of coating material. Results of the cold-hot iterative test showed that, regardless of the painting methods and layers, the defects such as crack or fuzz on surface were not produced. As the number of painting layers increased, the neutralization prevention as well as the chloride ion permeation prevention effects were increased. On the other hand, no difference was found between the painting methods. Reducing weight by abrasion of polymer paste coating material was $20\%$ comparing to that of cement mortar.

• Polymer(Korea)
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• v.37 no.4
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• pp.470-477
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• 2013

Multi-walled carbon nanotube (MWCNT) based nano-composite pastes having a high filler content are prepared for the facile fabrication of a counter electrode (CE) of dye-sensitized solar cell (DSSC). A polystyrene-based functional block copolymer is prepared through a controlled "living" radical polymerization technique, affording a surface modifier for the dispersion control of MWCNT in the paste. Physical dispersion through a ball-milling method additionally confirms the importance of the dispersion control, providing DSSC with enhanced processibility and improved solar-to-electricity energy conversion efficiency (${\eta}$) values. The performances of the DSSCs are further improved through the incorporation of minor amount of platinum (Pt) nanoparticles into the MWCNT pastes. The DSSC with the Pt/MWCNT hybrid CE exhibits very high ${\eta}$ values, which is superior to that of DSSC with the standard Pt CE.

• International Journal of Highway Engineering
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• v.3 no.4 s.10
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• pp.117-126
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• 2001

In this research, evaluation of adhesion in tension property of SBR-modified concrete to ordinary portland cement concrete was conducted with uniaxial direct tensile bond test which was proposed by Kuhlmann. A test set-up was fabricated in order to minimize the eccentric force by introducing a joint which might fully rotate. The main experimental variables were cement-latex ratios, surface preparations and moisture levels. The results obtained were as follows: The LMC specimen at 15% latex-cement ratio increased the adhesion in tension by range of 37% compared to that of conventional cement concrete. This might be due to latex film formed between cement paste and aggregate. The effects of surface preparation on bond of latex modified concrete to conventional concrete were significant at the conditions by sand paper and wire brush. A better bond could be achieved by rough surface rather than smooth. The saturated and surface dry (SSD) condition were considered to be the most appropriate moisture level followed by wet, finally by dry. Thus, a proper surface preparation and moisture level are quite necessity in order to obtain better bonding at LMC overlay.