• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.1005-1010
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• 2001

Recently, polymer-modified mortar has been studied for proposed use on industrial floors as top layers with thin thicknesses, typically 5~ 15mm. The purpose of this study is to evaluate basic properties of self leveling materials using polymer modifier as kinds of SBR, PAE, SUBA. Superplasticizer and thickener have been included in the mixes to reduce bleeding and drying shrinkage as well as in order to facilitate the workability required. The self leveling materials using four types of polymer dispersion are prepared with polymer-cement ratios which respectively range from 50%, 75%, and were tested for basic characteristics such as adhesion in tension, crack resistance test, rebound test after the preparative tests for unit weight, air content, consistency ratio etc. The results show almost as equal quality as existing commercial industrial flooring when mortar is modified by polymer dispersion. Adhesion in tension of polymer modified mortars using each SBR and PAE emulsion was over 10 kgf/$cm^{2}$. Crack or flaw derived from shrinkage is strongly dependent on the type of polymer dispersion because of each different total solid of polymer. It is judged that polymer modified mortar with self-leveling can be very well suited for Floor-finished.

• 콘크리트학회지
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• 제5권4호
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• pp.145-155
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• 1993

본 연구는 섬유보강 플라이애쉬$\cdot$석회$\cdot$석고 복합체의 역학적 특성을 실험적으로 구명하고, 그 제조방법을 제시한 것이다. 플라이애쉬$\cdot$석회$\cdot$석고 복합체는 PAN계 및 Pitch계 탄소섬유, 내알카리성 유리섬유와 폴리머 분산제를 사용하여 제조하였고, 배합조건별로 그 특성을 검토하였다. 연구결과, 플라이애쉬$\cdot$석회$\cdot$석고 복합체의 제조를 위한 소요서의 컨시스턴시와 강도를 얻기 위한 최적배합을 제안하였다. 또한, 섬유보강 플라이애쉬 석회 석고 복합체의 휨강도 및 휨인성은 섬유의 종류에 관계없이 섬유혼입율의 증대에 따라 현저히 개선되었으며, 압축강고는 섬유혼입율보다는 점유의 종류에 따라 크게 영향을 받았다. 한편, 폴리머 분산제를 혼입한 PAN계 탄소섬유보강 플라이애쉬$\cdot$석회$\cdot$석고 복합체의 비중은 폴리머 분산제의 혼입에 의해 크게 감소하였고, 동복합체의 압축강도, 휨강도 및 휨인성은 폴리머에 의한 영향은 거의 없고 섬유혼입율은 증대에 따라 현저히 개선되는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.793-797
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• 2005

This study was undertaken to examine the feasibility of recycling waste concrete fine aggregate to prepare polymer-modified mortars. The specimens of polymer-modified mortars were prepared by using styrene-butadiene rubber(SBR) latex and polyacrylic ester(PAE) emulsion as a polymer modifier. The formulations for specimens were prepared with various replacing ratios of waste concrete fine aggregates as parts of standard sand and various polymer cement ratios. For the evaluation of the performance of polymer-modified mortars, various physical properties were investigated. As a results, water cement ratio of polymer-modified fresh mortars increased with an increase of recycled fine aggregate, but decreased with an increase of polymer modifiers. The compressive and flexural strengths of polymer-modified mortars decreased with an increase of recycled fine aggregate, but flexural strengths increased with an increase of polymer modifiers.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.1017-1022
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• 2001

The bend resistance of coated reinforcing bar is greatly influenced by adhesion strength of bar and coating materials and transformation of coating materials to the bar. Expecially, tearing state or a limited microscopic cracks are predicted on the inside and outside of bending angle because of adhesion strength and elongation is very different with types of polymer materials using bar coating, and these parts are accelerated corrosion as penetration of bar corrosion effects factor. In this study, cement modified polymer are prepared four types and differ from polymer cement ratio of 50% and 100%, coating thickness of 250$\mu$m and 450$\mu$m, coating number, curing age of 3, 7, 14 and 280days, and then tested bend resistance as bending angle $90^{\circ}$, $135^{\circ}$ and $180^{\circ}$ for observe the microscopic demage effect according as bar bend. From the test results, when is used cement modified polymer as coating materials of bar, St/BA is showed excellent bend resistance than a polyacrylic emulsion and SBR because of softness. But it is to need attention because as coating parts are pressed down and tearing, also experimental study is proceeded to corrosion potential on the inside and outside of coated reinforcing bar.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.755-764
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• 2020

Due to pronounced mechanical performance and being environmental friendly, aqueous polymer isocyanate adhesive (API) has been widely applied in the production of formaldehyde-free wood products. In this study, flame retardant formaldehyde-free plywood was prepared by incorporation of flame retardants into the API adhesive. Partially phosphorylated poly (vinyl alcohol) (PPVA) which was prepared by reacting poly (vinyl alcohol) with phosphoric acid was used to replace PVA in API formula. In addition, Mg-Al layered double hydroxides (LDH) was chosen as additive flame retardant, replacing traditional filler CaCO₃ in API adhesive formula. And then, the flame retardant API adhesive with main agent (PPVA replacing PVA70wt.%, SBR emulsion 30wt.%), curing agent 10wt.% (accounts for of the main agent), and 20wt.% LDHs (accounts of the main agent) was used to prepare flame retardant plywood. The effect of application of PPVA and Mg-Al LDH on bonding strength of plywood was investigated. The flammability characteristics of the plywood were determined by cone calorimeter test (CCT). The results revealed that compared with the plywood prepared with API adhesive, the use of PPVA and LDH enhanced the flame retardancy of plywood without negatively affecting bonding strength. The CCT tests indicated that the heat release and smoke production flame retardant API plywood were lower than those of the ordinary API glued plywood. Promising developments for flame retardant API adhesive were expected in future applications of flame retardant formaldehyde-free plywood.