진공의 압력과 시간을 달리할 때 시멘트시험편의 유효공극률 변화 = Effective Porosity Variation of Cement Samples According to Vacuum Pressure and Time

다국어 초록 (Multilingual Abstract)

Effective porosity has been measured for cement specimen as a function of vacuum time and pressure in the vacuum saturation process. Six cement specimen are used; three of them are made of the same ratio of cement and sand, the other three are 100% cement mortar, of which average porosity is about 25% and 40%, respectively. Using the 6 samples, measured effective porosities are compared and examined with 5 different vacuum pressures (2, 4, 6, 8, 10 torr) and times (20, 40, 60, 80, 100 minute), respectively. Comparing measured effective porosity from experiments when vacuum time varies from 100 minute to 20 minute with 20 minute step and vacuum pressure is fixed to 10, 6, and 2 torr, average deviation decreases as 0.6, 0.5, and 0.2% respectively. Comparing measured effective porosity from experiments when vacuum pressure varies from 2 torr to 10 torr with 2 torr step and vacuum time is fixed to 100, 60, and 20 minute, average deviation increases as vacuum time decreases. These results can be a background of suggested method of ISRM that describes the vacuum time longer than 60 minute and vacuum pressure higher than 6 torr. In this study, only qualitative discussion can be possible for the effects on the effective porosity by decreasing 20 minute vacuuming time at the same pressure or by decreasing 2 torr of vacuum pressure at the same vacuum time. This is because the sample could not reached to perfectly dried condition even though the sample were dried at 105oC and following the ISRM suggested method, so that initial water content could not be the same at each experiment.

참고문헌 (Reference)

1 이상규, "진공 압력과 시간을 달리할 때시멘트시험편의 유효공극률 변화" 203-206, 2012

2 한국암반공학회, "암석의 공극률 및 밀도 측정 표준시험법" 16 (16): 95-98, 2006

3 이상규, "습식진공과 건식진공에 의한 시험편의 유효공극률 비교" 195-197, 2012

4 이상규, "수분분리기 및 이를 포함하는 수분 포획장치"

5 이상규, "건조과정에서 무게 모니터링을 통한 암석 시험편의 고체무게 산출 방법" 한국자원공학회 47 (47): 183-190, 2010

6 ISRM, "Suggested methods for determining water content, porosity, density, absorption and related properties and swelling and slake-durability index properties" 1979