• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.669-680
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• 1994

DMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and dodecyl-metacrylate containing long chain hydrocarbon group with hydrophilic and hydrophobic radicals. To facilitate water emulsification,acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measured by GPC, and C. H. N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier(PDCM-PDD) was prepared by blending of the guaternized acrylic copolymer synthesized above sodium silicate sodium gluconate oleic acid and triethanol amine. The result with prepared polymer dispersion of cement modfier was examined, and it was found that excellent waterproffing effect; Water permeability ratio is 0.44 under the water pressure of $100g/cm^2$ and 0.55 under $3kg/cm^2$, and water absorption ratio is 0.36~0.47 and 1.02 compressive strength ratio at mixed ratio of water/PDCM-PDD is 45 times.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.119-125
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• 2020

Research on high-attenuation concrete for the vibration reduction performance by mixing epoxy-based synthetic resins and aggregates is actively being conducted. The curing time of high-attenuation concrete is very short because water is not used, and the physical and dynamic properties are very excellent. therefore, it is expected to be widely used in building structures requiring reduction of interior-floor noise and vibration. Furthermore, A way to expand the applicability of the high-damping concrete mixed with polymer in the field of reinforcement material have been variously studied. In order to replace polymer concrete with ordirnary concrete and existing anti-vibration reinforcement material, it is necessary to review overall vibration reduction performance considering physical properties, dynamic properties, productivity and field applicability. In this study, the physical and dynamic properties of polymer concrete by epoxy mixing ratio compared with ordirnary concrete. As a result, the elastic modulus was similar. On the other hand, polymer concrete for the compressive, tensile, and flexural strengths was quite more excellent. In particular, the measured tensile strength of polymer concrete was 4-10 times higher than that of ordirnary concrete. it was a big difference, and the frequency response function and damping ratio was studied through modal test and finite element analysis model. The dynamic stiffness of polymer concrete was 20% greater than that of ordirnary concrete, and the damping ratio of polymer concrete was approximately 3 times more than that of ordirnary concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.94-104
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• 2013

Experiments were divided into two parts; one part is to understand the basic properties of high flowable VA/VeoVa-modified cement mortar with different polymer cement ratio (P/C) and the weight ratio of fine aggregate to cement (C:F) and the other part is to investigate the effect of surface water spread on the concrete substrate on adhesion in tension. To understand the basic performance, the specimens were prepared with proportionally mixing VA/VeoVa redispersible powder, ordinary portland cement, silica sand, superplasticizer and viscosity enhancing agent. Here, P/C were 10, 20, 30, 50 and 75% and C:F were 1:1 and 1:3. As the change of P/C and C:F unit weight, flow test, crack resistance and adhesion in tension were measured. Three specimens with good adhesion properties were selected among specimens with different P/C and C:F. The effect of surface water evenly sprayed on concrete substrate on adhesive strength is investigated. The results show that surface water on concrete substrate increases the adhesion in tension of high flowable VA/VeoVa-modified cement mortar and additionally improves the flowability compared to the non-sprayed case.

• Clean Technology
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• v.11 no.1
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• pp.1-12
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• 2005

In these studies, semibatch emulsion copolymerization of n-butyl acrylate (n-BA) as adhesive component and methyl metacrylate (MMA) as coagulant component was carried out in order to investigate the role of surfactant in aqueous phase for polymer cement. It was found that the particle size and concentration of final polymer are affected by surfactant type used. The effect of nonionic surfactants was shown in the decrease of polymer emulsion concentration and small emulsion particle in order of LE-50, NP-50 > CE-50, Tween 20 > TX-405 > Brij 35. In LE and NP (n=7-50) as nonionic surfactant, it could be obtained the stable polymer emulsion of 40% in aqueous phase with average particle size of 250-320 nm using over n=30. On the other hand, the effect of surfactant type in initial reactor charge was shown that when SDS as ionic surfactant was used, the polymer emulsion concentration was constant irrespective of the amount used, whereas CTAB as cationic surfactant and HN-100 as reactive surfactant were shown a tendency to the decrease of that. The effect surfactant type on final polymer particle size was shown in decrease by the order of SDS > CTAB > HN-100.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1066-1072
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• 1999

The physical properties of polymer concrete were investigated for development of high-performance construction materials. Various specimens of polymer concrete were prepared using unsaturated polyester resin as the polymer-binder with the various dosage of calcium carbonate as microfiller (5~20 wt %) and fine aggregate(10~50 wt %). For the evaluation of the physical properties of polymer concretes, tests such as compressive strength, flexural strength, water absorption test, hot water immersion test, acid resistance test and pore size distribution analysis were conducted. As a result, it is concluded that compressive and flexural strengths of polymer concretes increased up to 4 times than those of conventional cement concrete. Whereas the compressive and flexural strengths of polymer concretes tested after hot water immersion, compared with those of polymer concretes tested before hot water immersion, decreased about 67%, 47%, respectively. By hot water immersion, total pore volume and porosity(%) of polymer concretes were remarkable increased due to decomposition of polymer binder. And also, it is showed that water absorption(%) and weight loss(%) of polymer concrete specimens by acid immersion, compared with those of ordinary portland cement concrete, decreased about 1/100, 1/27, respectively.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.713-719
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• 2008

Various types of coatings have been developed for use as reinforcement in concrete and to resist chloride environment. The most commonly used coatings are inhibited and sealed cement slurry coating, cement polymer compositing coating and epoxy coating. Cement slurry offers passive protection, epoxy coating offers barrier protection whereas polymer coating offers both passive protection and barrier protection. Moreover, damage during handling of the steel may result in disbondment of the epoxy coating, which would increase the risk of localized corrosion. In the present study, inhibiting technique was used to increase the calcium hydroxide content at the interface up to 20%. Calcium hydroxide provides a high buffering capacity that resists a local fall in pH and thus maintains the alkaline environment necessary to prevent chloride corrosion. This study examines the use of a calcium hydroxide coating on the steel surface to enhance the pH buffering capacity of steel-concrete interface. Finally, the chloride threshold level (CTL) of polymer inhibitive coating calcium hydroxide is evaluated.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.491-498
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• 2012

This study examines setting shrinkage, coefficient of thermal expansion, and elastic modulus of unsaturated polyester( UP)-methyl methacrylate(MMA) polymer concrete, which is generally used for repair of portland cement concrete pavement and manufacturing of precast products. In this study, a series of laboratory test were conducted with variables such as UP-MMA ratio, shrinkage reducing agent (SRA) content, and test temperature. The results showed that the setting shrinkage ranged from 29.2 to $82.6{\times}10^{-4}$, which was significantly affected by test temperature. Moreover, the findings revealed that the coefficient of thermal expansion, elastic modulus and ultimate strain of UP-MMA based polymer concrete ranged from 21.6 to $31.2{\times}10^{-6}/^{\circ}C$, 2.8 to $3.3{\times}10^4$ MPa, and 0.00381 to 0.00418, respectively. The results of this study will be used as important data for design and application of UP-MMA based polymer concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.135-142
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• 2020

In the case of a concrete structure, vibration problems occur under various conditions because of its low damping performance. To solve this problem, a study on the high damping performance of the polymer concrete with hybrid damper has recently been increased. Since water is not used in polymer concrete, the curing time is short. Also, the physical properties and dynamic properties of polymer concrete are quite excellent. So polymer concrete is widely expected to be used for structural materials. The hybrid damper is the structural system that consists of steel balls and viscous fluid inside the pipe which is embedded in polymer concrete. It can reduce the structural vibrations through the energy dissipation mechanism of viscous fluid and steel balls. In this study, the physical and dynamic properties of polymer concrete with hybrid damper were compared with ordinary concrete. As a result, the elasticity coefficient and the strength of the polymer concrete with hybrid damper were so much excellent. In particular, the tensile strength was 6.5 to 10 times higher than ordinary concrete. The frequency response function and damping ratio were also compared. As a result, the dynamic Stiffness of the polymer concrete was 25% greater than that of ordinary concrete. The damping ratio of the polymer concrete was approximately 3 times higher than that of ordinary concrete. Although the dynamic stiffness of the hybrid damper showed similar tendency, the damping ratio was 3.5 times higher than that of ordinary concrete. Therefore, the polymer concrete with hybrid damper was superior to ordinary concrete.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.319-326
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• 2017

In this study, a lightweight geopolymer was prepared using by slag discharged from IGCC (Integrated Gasification Combined Cycle) power plant and its physical properties, the density and compressive strength, were analyzed as a function of the concentration of alkali activators, W/S ratio and aging times. Also the possibility of applying it to lightweight materials by adding Si sludge as a foaming agent to the geopolymerg was investigated. In particular, a complex composition of alkali activator and a pre-curing process were applied to improve the strength properties of lightweight geopolymers. While the compressive strength of the lightweight geopolymer using a single activator was 9.5 MPa, the specimen made with a complex composition of alkali activator had compressive strength of 2~5 times higher. In addition, the lightweight geopolymer with pre-curing process showed a compressive strength value of 18~48 % higher than that of specimen made with no precuring process. In this study, by using a complex activator and a pre-curing process. the maximum compressive strength of lightweight geopolymer was obtained as 40 MPa (The specimen was aged for 3 days and had density of $1.83g/cm^3$), which is comparable to cement concrete. By analyzing the crystal phase and microstructure of geopolymers obtained in this study using by XRD and SEM, respectively, it was confirmed that the flower-bud-like zeolite crystal was homogeneously distributed on the surface of the C-S-H gel (sodium silicate hydrate gel) in the geopolymer.

• Polymer(Korea)
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• v.36 no.2
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• pp.216-222
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• 2012

We synthesized microcapsule absorbent with crosslinked poly(styrene-$alt$-maleic anhydride) (PSMA) as a core and PSMA as a shell by a precipitation polymerization method for the delayed absorption of excess water in cement mortar. cPSMA-PSMAs with core-shell structure were synthesized with ratios of 1/1, 1/2 and 1/3 as core monomer mass to shell monomer mass to control shell thickness. We observed the hydrolysis of PSMA in cement-saturated aqueous solution by a FTIR spectrometer. We observed good core-shell structure microcapsules for 1/2(cPSMA #3), but observed incomplete core-shell structure for 1/1(cPSMA #2) and 1/3(cPSMA #4) of core/shell monomer ratios. The swelling ratio of cPSMA #3 in cement-saturated aqueous solution was increased until 20 min. After that it was decreased until 2 hrs swelling time, and they started to increase again. The viscosities of cement paste with cPSMA #3 microcapsules were very slowly increased until 1 hr and increased fast after 1.5 hrs. Cement mortar with 0.5 wt% cPSMA #1 having only core part showed about 5% increase in compressive strength compared to that of plain cement mortar. cPSMA #3 added cement mortar showed the highest compressive strength with 7% increase.