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Effect of Absorbent Materials and Initial Sealed Curing on Drying Shrinkage and Compressive Strength of Hwangtoh Mortar

흡수성 물질과 초기 밀봉양생이 황토 모르타르의 건조수축과 압축강도에 미치는 영향

  • Received : 2016.07.14
  • Accepted : 2016.08.16
  • Published : 2016.11.01

Abstract

This study investigates the effect of the absorbent materials on the material properties(compressive strength and drying shrinkage) of natural hwangtoh mortar which is one of the traditional building material in Korea. The absorbent materials used are seaweed paste and Super-Absorbent Polymer(SAP). In addition to the absorbent materials, the initial sealed curing recommended by the standard specification of properties for Korean traditional building materials is also a main interest of this study. Based on the test results of 28 days compressive strength and converged drying shrinkage, it is confirmed that the initial sealed curing for 7 days is effective to reduce the drying shrinkage and to enhance the compressive strength. Thus, it is verified that the recommendation is reasonable and has positive effects on the properties of the mortar. Next, the test results show that the addition of absorbent materials into the mortar is also effective to the two properties depending on their absorption capacity. Thus, it is more effective to use SAP than the seaweed paste because of higher absorption capacity. However, both the initial sealed curing and keeping total water contents of the mortar are required to show this effectiveness. Lastly, the compressive strength is inversely proportional to the drying shrinkage. By using this relation, the reason of the increase of compressive strength due to the initial sealed curing or the addition of absorbent materials is quantitatively explained.

이 연구에서는, 우리나라 전통 건축재료 중 하나인 천연 황토 모르타르에 사용되어 온 해초풀과 현대적 재료인 고흡수성수지(Superabsorbent Polymer, SAP)와 같은 흡수성 물질이 이러한 모르타르의 건조수축과 압축강도에 미치는 영향이 조사되었다. 흡수성 물질과 더불어 문화재표준시방서에서 권고하는 초기 밀봉양생의 효과 역시 검토되었다. 실험에 의한 28일 압축강도와 수렴한 건조수축 변형율의 검토 결과, 우선 초기 7일간의 밀봉 양생은 강도향상과 수축저감에 효과적이었다. 따라서, 문화재표준시방서의 권고는 합리적이며 실효성이 있는 것으로 검증된다. 흡수성 물질의 혼입 역시 두 재료특성에 있어 효과적인데, 그 효과는 물질들의 흡수 능력에 의존한다. 따라서, 흡수 능력이 더 높은 SAP을 사용하는 것이 해초풀을 사용하는 것보다 더 효과적이다. 그러나, 이러한 것들이 유효하기 위해서는 초기 밀봉양생과 물이 추가되지 않는 조건들이 함께 따라야 한다. 마지막으로, 황토 모르타르의 압축강도의 증가는 건조수축의 감소와 선형적으로 관계한다. 이러한 선형 상관성에 의해, 초기밀봉 양생 또는 흡수성 물질의 혼입에 따른 모르타르의 압축강도 증가하는 원인이 정량적으로 설명될 수 있다.

Keywords

References

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