ASTM C191:2013 pd ffree download – Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle.
14. Procedure A
14.1 Quickly tern the cement paste. prepared as desenbed in the section on preparation of cement paste, into a ball with gloved hands and toss six times from one hand to the ocher, maintaining the hands about 150 into (6 In.) apart. Mess the ball. resting In the paine of the hand, into the Larger end of the conical ring. G. Fig.
*her hand, completely filling the sing with paste. Remos’e the excess a the larger end by a single movement of the palm of the hand. Pta-c the ring on its larger end onto the nonabssa’ptise plale. H. and slice oIl the escess paste at the snsaller end at the top of the nng by a single oblique stroke of the trowel held al a slight angle with the top of the ring. Smooth the top of the specimen. if necessary. with one or two light touches of the pointed end of the trowel. During the operation of caning and smoothing, rake care not to compress the paste. lnitneehately alter molding, place the test ‘pecitnen in the moist cabinet or moist naini and allow it to remain there escept when penetration measurements are being made. The specimen shall remain in the conical mold, supported by the non-absoqxive plate throughout the test period.
14.2 lime of Veiling I)esertnsnarion Allow the time of setting specimen to remain in the moist cabinet or moist nnn for 30 mm after molding without being disturbed, Determine the penetration of the I-nun needle at this time and esery IS mm thereafter fesety 10 enin for Tpe Ill cemenrs until a penetration of 25 mm cc less is obtained. Perlitmi the penetra hon test hy lowenng the needle I) of the rod a until it rests on the surface of the cement paste. Tighten the setscrew, F. and set the indicator. F. at the upper end of the scale, or take an initial reading. Release the rod quickly by releasing the set screw. F. and allow the needle to settle fur 30 s; then take the reading to determine the penetration. At the option of the tester, if the passe is obs’ioualy quite soft on the early readings. retard the fall of the rod to asoid bending the I-mm needle. but when actual penetration measurements to determine the time of setting are made, release the rod only by the setscrew. Make each penetration lest at least 3 mm away frotn any previous penetration and at least 10 man away front the inner side of the mold. Record the results of all penetration tests and, by interpolation, determine the titne when a penetration of 25 nun is obtained. ‘Die elapsed time between the initial contact of cement and waler and the penetration of 2.5 toni is the Vicat time of setting or Vicat initial time of setting.
14,3 Detennine the Vicat final time of setting end point to he the first penetration measurenient that does not nsark the s4tecimnen surface with a complete cittular impression. Verify tinal set by performing two additional penetration measure’ meats on dillerent areas of the specimen surface (tNain verification measurements within 90 s of the first “final set” measurement.