논문 상세보기
pp.79-86
PURPOSES : The purpose of this study is to suggest a thermal expansion coefficient measurement method using an embedded strain transducer (EST) and vibrating wire gauge (VWG), as well as to evaluate the reliability of the proposed methods by comparing them with the AASHTO T 336-10 standard method.
METHODS : To apply the AASHTO 336-10 test method, which is the criterion for reliability evaluation, a reference specimen using stainless steel (sus304) is manufactured, and a thermal expansion coefficient of 17.308με/°C is obtained based on ISO regulations. Using the reference specimen, the correction factor of the thermal expansion coefficient measurement equipment is measured to be 2.93με/°C, and using this value, the thermal expansion coefficient of the mortar specimen containing the embedded gauges is measured accurately. The reliability of the proposed experimental method is evaluated by measuring the thermal expansion coefficient of the embedded gauge with temperature compensation and then comparing it with that of the reference specimen.
RESULTS : The coefficient of thermal expansion of the mortar specimen is measured to be 12.423με/°C based on AASHTO 336-10, 11.963με/°C using the EST method, and 12.522με/°C using the VWG method. Based on the results obtained using the AASHTO method, the embedded gauges show a difference of 1%~3% in terms of the average results, as well as a difference in the standard deviation of 0.059~0.186. Therefore, our level of confidence in the thermal expansion coefficient experiment using the embedded gauges is high.
CONCLUSIONS : When using the AASHTO 336-10 test method, the thermal expansion coefficient should be obtained by measuring the length change of the specimen; however, some engineering judgment of the experimenter is required when the measurement values fluctuate during the temperature stabilization period. In the thermal expansion coefficient test using embedded gauges (EST and VWG), temperature compensation must be performed. Furthermore, it is assumed that the temperature difference between the water tank and test specimen does not significantly affect the thermal expansion coefficient measurement because the important point is not the actual temperature value but the temperature gradient. For reliability evaluation, a statistical significance review of the strain distribution by measurement method is performed via a T-test comparing with the AASHTO test result (12.423με/°C) and the reliability level for each measurement method remains confidential.
1. 서론
2. 콘크리트 열팽창계수 시험법 고찰
3. 열팽창계수 측정방식에 따른 신뢰도 평가
3.1. 신뢰도 평가 방법
3.2. 시험체 제작
3.3. 기준시편 시험
3.4. 기준 시편을 이용한 AASHTO 336-10 시험법의수정계수 측정
3.5. 모르타르 시편의 CTE 측정
3.6. 매립형 게이지 온도보정 시 온도 선택
3.7. 매립형 게이지를 이용한 CTE 측정
3.8. CTE 측정 방식에 대한 신뢰도 평가
4. 결론
REFERENCES
