Experimental Study on Setting Time of Cement Paste Mixed Accelerating Admixtures Heo Gweon; Choi Hong-Shik; Yi Seong-Tae;
The setting time is a very important factor affecting the quality of tunnel lining and reinforcement of inclined slope etc. Currently, however, the quality criteria of accelerating admixture to improve it is not established well. In this study, evaluation on setting time measuring methods of cement mixed a accelerating admixture (AA) was performed using Gillmore and Vicat needle test methods. For both test methods, the setting time for addition at a time was better than post addition regardless of initial setting and final setting. For Gillmore needle test method, two types of measuring methods were selected and it is noted that setting time with cement type under the same accelerating admixture can be different. Accordingly, manufacturing company shall develop a less sensitive accelerating admixture to cement type. For Vicat needle test method, six types of measuring methods were used and a proper measuring method of the admixture were proposed as follows: (1) the temperature of materials used shall be controlled exactly and (2) to evaluate its properties, an admixture usage of (ratio of cement weight) is recommended.
KCI-SC 102, '숏크리트용 급결제 품질규격' 콘크리트 표준시방서, 한국콘크리트학회,1999
현석훈, 한기석, '숏크리트 품질에 미치는 재료 및 시공 조건의 영향' 한국콘크리트학회 봄학술발표회논문집,6 권 1호 1994, PD.277-232
ASTM C 1102-94, Standard Test Method for Time of Setting of Portland-Cement Pastes Containing Accelerating Admixtures for Shotcrete by the Use of Accelerating Admixtures for Shotcrete by the Use of Gillmore Needles, ASTM, 1994, 2pp
KS L 5108, '비카트 침에 의한 수경성 시벤트의 응결 시간 시험 방법', 한국표준협회(KSA), 2002, 9pp