등가재령 방법에 의한 혼화재 치환 고강도 모르타르의 자기수축 평가 = Estimation of Autogenous Shrinkage of High Strength Mineral Admixture Mortar by Equivalent Age Method

다국어 초록 (Multilingual Abstract)

The objective of this research is to investigate an effect of curing temperature on autogenous shrinkage of high strength mortar with 0.15 water-to-binder ratio incorporating fly ash (FA), blast furnace slag (BS), and silica fume (SF) in terms of equivalent age. The replacement ratios of FA, BS, and SF were varied from 10 % to 30 %. The curing temperatures were prepared with 5°C, 20°C and 35°C as the parameters based on the assumption of the climate condition in the practical field. Non-linear regression model applying equivalent age was used to estimate the autogenous shrinkage.

(1) The autogenous shrinkage of the concrete showed rapid shrinkage within the first three days while slow trend of shrinkage was shown after third day.
(2) Depending on the curing temperature, as the curing temperature was increased, the amount of shrinkage was increased. Namely, although there was no significant change at early ages, as the curing age was increased, relatively more shrinkage was observed in 35°C while less shrinkage was observed at 5°C for same ages.

(3) Although there are significant differences in 5°C of curing temperature conditions, similar shrinkage was observed in both 20 and 35°C, and thus it was considered that evaluation of maturity is hard to apply in these conditions.

(4) When using the Ea value at hardening phase for analysis of autogenous shrinkage depending on equivalent age, it is considered that more accurate evaluated results can be obtained. The accurate selection of Ea value will contribute on the evaluation of temperature dependency on autogenous shrinkage.

(5) As an analysis of correlation between setting and hardening phases using Tazawa model and power model, better correlationship was achieved for hardening phase than setting phase and power model showed better correlationship than Tazawa model.

In this research scope, as a result obtained from the hydration under the constant curing conditions, the influence of curing temperature on autogenous shrinkage was evaluated using equivalent age method, and it is considered that accurate Ea value selection is required based on the conditions of mix design and mixed materials for entire life term for accurate analysis.

목차 (Table of Contents)

• 1. 서 론 1
• 1.1 연구배경 및 목적 1
• 1.2 연구범위 및 방법 2
• 1.3 연구동향 5
• 1.3.1 국외의 연구동향 5
• 1.3.2 국내의 연구동향 6
• 2. 이론적 고찰 9
• 2.1 콘크리트의 온도 의존성 9
• 2.1.1 콘크리트의 구성 9
• 2.1.2 콘크리트의 수화반응과 온도의 영향 10
• 2.1.3 콘크리트의 강도증진 18
• 2.2 적산온도 및 등가재령 19
• 2.2.1 적산온도 및 등가재령의 개념 19
• 2.2.2 적산온도 및 등가재령의 예측모델 21
• 2.3 고강도 콘크리트의 자기수축 30
• 2.3.1 자기수축의 정의 30
• 2.3.2 자기수축의 메커니즘과 콘크리트의 수분이동 32
• 2.3.3 자기수축의 영향인자 42
• 2.3.4 자기수축 예측 모델 46
• 3. 실험계획 및 방법 51
• 3.1 실험 개요 51
• 3.2 실험 계획 51
• 3.3 사용 재료 53
• 3.3.1 시멘트 53
• 3.3.2 잔골재 54
• 3.3.3 혼화재료 54
• 3.4 실험 방법 55
• 3.4.1 굳지 않은 모르타르 실험 55
• 3.4.2 경화 모르타르 실험 58
• 4. 실험결과 및 분석 61
• 4.1 개요 61
• 4.2 혼화재 치환 모르타르의 특성 61
• 4.2.1 굳지 않은 모르타르의 특성 61
• 4.2.2 경화 모르타르의 특성 65
• 4.3 양생온도에 따른 자기수축 특성 68
• 4.3.1 양생온도별 재령경과에 따른 자기수축 68
• 4.3.2 적산온도에 따른 자기수축 84
• 4.4 등가재령 방법에 따른 자기수축 해석 100
• 4.4.1 활성화 에너지(Ea)의 산정 100
• 4.4.2 등가재령에 의한 응결시간 예측 106
• 4.4.3 등가재령에 의한 자기수축 특성 및 평가 116
• 5. 결 론 149
• 참고문헌 151
• ABSTRACT 159