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질산스트론튬 수용액 표면처리에 의한 수화시멘트 복합체의 휨강도 개선 KCI 등재

Surface Treatment Using Strontium Nitrate Solution to Improve Strength of Hydrated Cement Composites

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한국도로학회논문집 (International journal of highway engineering)
한국도로학회 (Korean Society of Road Engineers)
초록

PURPOSES : The effects of strontium cations on the strength of hydrated cement composites as well as the morphology and chemical composition changes of cement hydrates due to strontium treatment are investigated in this study. Subsequently, the potential of a strontiumbased aqueous solution as a near-surface treatment method for hydrated cement composites is evaluated.
METHODS : To supply strontium cations to a hydrated cement composite, a 30% strontium nitrate aqueous solution was used. Cement paste (w/c = 0.4) specimens were prepared and cured in the 30% strontium nitrate aqueous solution, which allows the strontium ions to penetrate into the specimen and treat the near-surface region. Compressive and flexural strength tests were performed on both specimens treated by the strontium ions and untreated specimens cured in deionized water, and the test results were compared. To investigate the changes in the morphology and chemical compositions of the cement hydrates due to the treatment, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analyses were performed.
RESULTS : The results of the strength tests indicate that both the compressive and flexural strengths of the specimens cured in the 30% strontium nitrate aqueous solution improved significantly compared with the specimens cured in deionized water for the same duration. In particular, the strontium nitrate aqueous solution shows greater improvement in terms of the flexural strength compared with the compressive strength. The maximum penetration depth of strontium into the hydrated cement composite is 5 mm during the first 7 d of immersion and increases to 6.5 mm during the subsequent 14 d. The SEM results show that the microstructure of the hydrated cement composite is densified by the strontium nitrate aqueous solution treatment. The EDS results show that morphology and chemical compositions of the cement hydrates are altered. This implies that the strontium cations can be combined with C–S–H and C–S–A–H phases to form new types of hydrates.
CONCLUSIONS : The experimentally results show that the strength of hydrated cement composites can be improved by modifying their near-surface regions via the strontium cation penetration technique. This implies that the strontium-based aqueous solution exhibits high potential for the maintenance and rehabilitation of concrete structures.

목차
ABSTRACT
1. 서론
2. 실험방법
    2.1. 재료 및 시편
    2.2. 강도특성 실험
    2.3. DIC (Digital Image Correlation)
    2.4. 미세구조 분석
3. 실험결과 및 토의
    3.1. 강도특성
    3.2. 미세구조
4. 결론 및 고찰
REFERENCES
저자
  • 성주경(상명대학교 건설시스템공학과 학사과정) | Sung Jookyeung
  • 조병휘(상명대학교 건설시스템공학과 교수) | Cho Byoung Hooi Corresponding author