Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Hardness and Rebound Properties of Sprayed Green Soil Produced with Functional Additives for the Application to Steep Slopes

기능성 첨가재를 적용한 급경사면용 녹생토의 경도 및 리바운드 특성

  • 이병재 (대전대학교 토목공학과) ;
  • 김효정 (제이엔티아이엔씨 기술연구소) ;
  • 김윤용 (충남대학교 토목공학과)
  • Received : 2018.07.23
  • Accepted : 2018.12.07
  • Published : 2018.12.31
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Abstract

In this study, the improved performance of sprayed green soil was evaluated by incorporating functional additives. The optimal mixing ratio of the thickener and super-absorbent polymer, as an additive for moisture supply to the growth of plants within the range of mixing ratios that gives sufficient strength of green soil, was 5% and 1%, respectively. Using Portland cement as a main binder, the pH of the green soil was 9.1. To solve this alkali problem, the mixing proportion was improved so that the pH of the green soil was approximately 7.2 by mixing more than 10% of the chelate resin. The soil conductivity was measured to be 280 ~ 350mS/m under all the mixing conditions. This satisfied the criterion of less than 1000mS/m on the slope surface. As a result of measuring the soil hardness of the green soil prepared under the optimal mixing conditions of functional additives, it satisfied the criteria of 18 ~ 23mm when sprayed under a 1 bar pressure. The rebound rate was less than 15% when spraying green soil on a 75 % slope, and the hardness of the sprayed green soil was more than 18 mm.

본 연구에서는 급경사면서의 식생기반재 부착 및 녹화성능 확보를 위해 혼입한 기능성 첨가재의 성능 평가를 수행하였다. 기능성 첨가재의 혼입조건에 따른 평가 결과, 급경사면의 부착이 가능하면서 식물의 생육에 원활히 수분 공급을 위한 기능성 첨가재로서 증점제 및 고흡수성 폴리머의 적정 혼입율은 각각 5%, 1% 인 것으로 판단된다. 시멘트 계열의 경화재로 인하여 높아진 pH에 대한 대책으로서 킬레이트 수지 10% 이상 혼입시 pH가 약알칼리에서 중성으로 회복되었다. 토양 전도도 평가 결과, 모든 배합조건에서 254~340mS/m으로 측정되어 기준인 1,000mS/m이하인 기준을 만족하였다. 기능성 첨가재의 최적 배합조건으로 도로비탈면 녹화공사의 설계 및 시공 지침에서 제시하는 경도를 측정한 결과 1bar의 압력으로 시공할 때, 18~23mm의 기준을 만족하였다. 급경사면에 대한 부착강도 평가를 위해 경사면 각도조건에 따라 분사 후 리바운드량과 산중식 경도계를 이용한 경도를 측정한 결과, 75도 각도에서도 리바운드율 15%미만, 경도 18mm이상의 성능 확보가 가능하였다.

Keywords

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Fig. 1. Moisture content

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Fig. 2. Soil acidity(pH)

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Fig. 3. Electrical conductivity

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Fig. 4. Hardness and compressive strength test results

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Fig. 5. Green soil spray photograph by slope condition

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Fig. 6. Rebound rate test results

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Fig. 7. Hardness test results

Table 1. Chemical characteristics of thickener and super absorbent polymer(%)

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Table 2. Environmental characteristics of chelate resin

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Table 3. Mix proportion of binder

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Table 4. Mix proportion of green soil

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