• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.529-538
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• 2021

In this study, the compressive strength and water contact angle were measured before and after surface abrasion of mortar specimens prepared by mixing two types of water repellents and two types of sands. In addition, the hydration products and chemical bonding of cement mortar by repellent were examined using X-ray diffraction(XRD), thermogravimetry-differential thermal analysis(TG-DTA), and Fourier-transform infrared spectroscopy(FT-IR) to evaluate the performance of these cement mortar mixtures as repair materials. We found that the compressive strength of the cement mortar with water repellent added was decreased compared to that of the plain cement mortar, and that of the oligomeric system was higher than that of the monomeric system. We further found that the contact angle of mortar with water repellent added was increased compared to that of the plain cement mortar, and that of the oligomeric system was increased compared to that of the monomer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.92-95
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• 2001

고분자 복합체 절연재료는 porcelain 이나 glass 같은 세라믹 소재의 재료와 비교하여 옥외사용 시간의 관점에서 더 뛰어난 특정을 발휘한다. 그러나 노화되었을 때, 이들 옥외용 절연재료의 성질은 발수성이나 흡수성등과 같은 절연재료의 표면특성에 의해 변화한다. 이러한 표면특성의 변화는 누설전류에 의한 트래킹 (tracking), 침식 (erosion) 및 섬락현상(flashover) 등의 유전체 파괴에 이르게 한다. 본 연구에서는 고분자 복합체 절연재료로 널리 이용되고 있는 EPDM의 발수특성을 향상시키기 위해 기존에 이용되던 무기물 첨가제인 alumina hydrate(ATH)이외에 발수성이 뛰어난 실리콘 고무를 상용화제를 이용하여 블렌드하고, 각종 유기 첨가제 및 무기물 보강제를 이용하여 EPDM/Silicone 복합체를 제조하였다. EPDM/Silicone 복합체의 인장강도 및 유전강도는 실리콘의 함량이 증가할수록 낮아졌으며, 촉진 노화시험을 실시한 결과 $120^{\circ}C$까지 인장강도 및 신율을 유지하였다. 유전강도의 측정결과 복합체의 접촉각과 표면에너지 측정결과 Silicone 고무의 함량이 증가할수록 접촉각은 증가하고, 표면에너지는 낮아졌다. 경사평판법에의한 내트래킹성 측정결과 실리콘 함량이 증가할수록 내트래킹성은 우수하였으며, 실리콘 함량이 30%인 복합체에서는 트래킹 및 침식이 진행되지 않았다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.76-77
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• 2021

compared and reviewed the water repellency and strength characteristics by controlling the surface stamping size and fine aggregate ratio of cement mortar mixed with water repellent as a method to control the ecological imitation surface structure. As a result of measuring the contact angle, the higher the ratio of fine aggregate, the larger the contact angle. The contact angle increased when the surface structure was changed by stamping, and increased as the stamping size became smaller. In the surface stamping of mesh#150, the contact angle was particularly increased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.50-58
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• 2020

When the concrete surface layer is damaged, The method of impregnating the concrete surface with a water repellent cannot secure the expected durability. Recently, various waterproofing and water-repellent materials were mixed into concrete or mortar to secure water repellency even inside cracks, but compressive strength was greatly reduced. In order to overcome the decrease in compressive strength, there has not yet been a study using the merits of organic and inorganic materials at the same time, so in this study, the physical properties and water repellency performance were evaluated by mixing an organic/inorganic composite water repellent appropriately mixed with an organic and inorganic material into the mortar. When mixed with organic/inorganic water repellent, the flow and air content were reduced by about 10% and 50% compared to the Liquid specimen. In the case of the P6L1 specimen, it was confirmed that the compressive strength decreased by about 3.5% compared to the non-mixed mortar at 39.5 MPa, the same as the existing water repellent, Powder. Water-repellent performance The organic-inorganic composite water repellent mixture specimen confirmed higher water repellency than the existing water repellent mixture powder, and the chloride penetration resistance evaluation result showed that the organic-inorganic composite water repellent mixture specimen reduced the passing charge by about 45% compared to the non-mixed mortar. In summary, it is judged that the P5L1 organic/inorganic composite water repellent mixed with a powder water repellent and a liquid water repellent in a ratio of 5:1 is the most reasonable to prevent the decrease in compressive strength and secure water repellency.

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.31-39
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• 2021

The aim of this paper is to improve durability of cement paste by imparting hydrophobicity to the surface and sphere of cement-based materials. A cement paste mixed with a silane/siloxane-based water repellent, and the initial hydration performance, flow performance, and age-specific compressive strength were measured. In addition, the water contact angle, SEM, and XRD before and after surface polishing were measured. When 0.5% of the silane/siloxane-based water repellent was mixed into the cement paste, the compressive strength increased, but the compressive strength decreased as the mixing amount increased by 1.5% and 3.0%. When a silane/siloxane water repellent was incorporated into the cement paste, the hydrophilicity was improved and the contact angle was increased due to hydrophobicity. In addition, the contact angle after surface polishing was found to be larger than the contact angle before surface polishing.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1172-1177
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• 2000

최근 콘크리트 보호 재료는 코팅을 이용하는 과거의 방법에서 함침을 이용하는 기법으로 전환하였다. 이중 발수제는 콘크리트의 표면의 특성을 변화시키는 것으로 친수성의 콘크리트를 소수성 물질을 결합시켜 물에 의한 젖음을 방어하는 것으로 콘크리트에 사용하였을 경우 콘크리트의 고유한 표면 장력을 작게 변화시키고 장력이 큰 물질 중의 하나인 물의 흡수를 방어하게 한다. 본 실험은 발수제의 성능 평가를 위하여 다공질의 재료인 콘크리트의 접촉각을 측정하여 그 변화를 관찰하였으며, 발수제들의 우수한 기능 중의 하나인 통기성을 시편의 중량 감소로 측정하였다. 발수제로 n-octyl ethoxy silane을 사용한 콘크리트 시편의 흡수 능력은 사용하지 않은 것의 약 10% 정도로 측정되었으며 시편의 수분 중량 감소는 7일 동안 90~130%로 관찰되어 통기성이 유지되어 콘크리트의 강도 유지에 효과적임을 알 수 있었다. 또한 겉보기 접촉각은 처리하지 않은 시편에서 24~33$^{\circ}$로 측정되었으나 처리된 시편의 최초면에서 130~141$^{\circ}$이었으며 2mm의 연마면에서는 127~132$^{\circ}$로 측정되어 콘크리트 표면 장력 변화가 유지되고 있음을 알 수 있었다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.142-147
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• 2003

고분자 애자용 재료로 EPDM, 폴리에틸렌, 에폭시, 실리론 고무 등이 사용되고 있으며, 이중 실리콘 고무는 내후성, 내트랙킹성, 내아크성, 내환경성, 발수성등이 우수하다는 것이 많은 연구를 통해 밝혀졌다. 그러나, 옥외용 고분자는 다양한 환경에 의한 열화에 의해 낮은 인열강도를 나타내고 반복 열화에 따라 전기적 특성과 기계적 강도가 급격히 저하하는 단점을 가지고 있다.(중략)

• Polymer(Korea)
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• v.31 no.1
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• pp.31-36
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• 2007

It has been reported that the surface properties of the plasma treated material were changed while maintaining its bulk properties. In this study, surface modification of nylon fiber by plasma treatment was tried to attain high water-repellency Nylon fiber was treated with RF plasma under a vacuum system using various parameters such as gas specious, processing time and processing power. Morphological changes by low pressure plasma treatment were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Moreover, the mechanical and inherent properties were analyzed by tensile strength, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The high water-repellency property of nylon fiber was evaluated by a water-drop standard test under various conditions in terms of aging effect. The results showed that the water-repellency of plasma-surface-treated nylon fiber was greatly improved compared to untreated nylon fiber.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.42-49
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• 2020

This paper is a basic study to improve durability by imparting hydrophobicity to the surface and sphere of cement-based materials. A cement mortar to which a silane/siloxane-based mixed water repellent was added was prepared, and its initial hydration performance, flow performance, and compressive strength were measured. In addition, after the surface was abraded, the water contact angle and water absorption were measured. The flow of cement mortar to which the water repellent was added was found to decrease up to 1.5% in the addition amount of the water repellent agent, and increased at 3.0% in the addition amount. It was found that the setting time of the cement paste was delayed in both the initial setting and the termination when the water repellent was added. It was found that the compressive strength decreased from 3.0% of the maximum added amount of the water repellent to a maximum of 30%. The contact angle was found to increase when the water repellent was added to the cement mortar, and the contact angle after surface polishing was found to be larger than before surface polishing. The addition of the water repellent showed hydrophobicity not only on the surface but also on the surface and cross section damaged by polishing. The water absorption rate was found to decrease when the water repellent was added to the cement mortar, and the water absorption rate after surface polishing was found to be greater than before surface polishing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.99-100
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• 2019

Water repellent and waterproofing agents fail to act work properly if cracks or detachment occurs outside. The method of making mortar was tested by classifying it into two methods: direct water-repellent put in concrete and water-repellent spray to sand method. It was found that the compressive strength was decreased as the amount of water repellent was increased. As a result of measuring the contact angle, all of the specimens were hydrophobic. The spray method showed greater water repellent effect than the direct mixing method.