Visit FileOpen to see the full list. December Methods of testing cement. Determination of setting times and soundness. March Methods of testing cement. Determination of setting time and soundness. Our policy towards the use of cookies Techstreet uses cookies to improve your online experience. Cement paste of standard consistence has a specified resistance to penetration by a standardplunger. The water required for such a paste is determined by trial penetrations of pastes withdifferent water contents.
The setting time is determined by observing the penetration of a needle into cement paste of standardconsistence until it reaches a specified value. The soundness is determined by observing the volume expansion of cement paste of standardconsistence as indicated by the relative movement of two needles. The tolerances shown in Figures 1 and 2 are important for correct operation of the equipment in thetesting procedure.
When regular control measurements show that the tolerances are not met,theequipment shall be rejected, adjusted or repaired. Records of control measurements shall be kept. Acceptance measurements on new equipment shall cover mass,volume,and dimensions to theextent that these are indicated in this document paying particular attention to those critical dimensionsfor which tolerances are specified. In those cases where the material of the equipment can influence the results, the material is specifiedand shall be used.
The approximate dimensions shown in the figures are provided as guidance to equipmentmanufacturers or operators.
Raise the needle to the stand-by position. NOTE Automatic setting time apparatus may be used, in which the needle Figure 1 d is used for determination of final setting times provided that they have been calibrated against the reference method.
Place the filled mould and base-plate in the container 6. After a suitable time, position the mould, base plate and container under the needle of the Vicat apparatus.
Lower the needle gently until it is in contact with the paste. Then release the moving parts quickly and allow the needle to penetrate vertically into the paste. Read the scale when penetration has ceased, or 30 s after the release of the needle, whichever is the earlier. Record the scale reading, which indicates the distance between the end of the needle and the base- plate, together with the time from zero see 5.
Repeat the penetration on the same specimen at conveniently spaced positions, not less than 8 mm from the rim of the mould or 5 mm from each other and at least 10 mm from the last penetration position, at conveniently spaced intervals of time, e. Between penetrations keep the specimen in the container in the temperature controlled enclosure 6.
Clean the Vicat needle immediately after each penetration. Retain the specimen if determination of the final setting time is to be made. NOTE Accuracy can be improved by reducing the time interval between penetrations near the setting time. Immerse the mould and base-plate in the container 6.
Repeat the penetrations on the same specimen at conveniently spaced positions, not less than 8 mm from the rim of the mould or 5 mm from each other and at least 10 mm from the last penetration position, at conveniently spaced intervals of time, e. Record the time at which the needle first penetrates only 0,5 mm into the specimen, together with the time from zero see 5. This time is that at which the ring attachment first fails to mark the specimen and may be accurately established by reducing the time interval between penetrations near the final setting time.
The final setting time shall be confirmed by repeating the test in two other positions. The mould shall be of non-corrodible spring metal, e. Each plate shall be larger than the mould. The cover plate shall weigh at least 75 g; an additional small mass may be placed on the plate to satisfy this requirement. Place a lightly oiled Le Chatelier mould on the lightly oiled base-plate and fill it immediately without undue compaction or vibration using only the hands and a straight-edged implement, if desired, to level the top surface.
During filling, prevent the split in the mould from accidentally opening, e. Cover the mould with the lightly oiled cover plate, add the additional mass, if necessary, and then immediately place the complete apparatus in the humidity room or cabinet.
NOTE 2 Where it can be shown that the expansion after a shorter boiling period is the same as that after 3 h, such a shorter period may be used. At the end of the boiling period the distance B between the indicator points may be measured, to the nearest 0,5 mm.
Remove from the heat and allow the mould to cool to laboratory temperature. Measure the distance, C, between the indicator points, to the nearest 0,5 mm. If the expansion exceeds the specification limit for the cement a repeat determination shall be carried out. Report the value of C - A , or the mean of two values when a repeat determination has been carried out, to the nearest millimetre.
NOTE Where it can be shown that the conditions of the test lead to no significant difference between measurements B and C, the difference B - A may be reported since this reduces the time needed for the test. Then retest the cement according to 7. Alternative method for setting time tests A. NOTE The specifications for cements and other products will state when this alternative method is to be used.
Fill a Vicat mould in accordance with 5. Place the filled mould and base-plate in the room or humidity cabinet and after a suitable time, position the mould, base-plate and container under the needle of the Vicat apparatus. Record the scale reading, which indicates the distance between the end of the needle and the base- plate, together with the time from zero.
Between penetrations keep the specimen in a room or humidity cabinet. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision.
Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services.
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