Gillmore needles

The drawback with the use of the Gillmore needle is that it is not a test of any well-defined rheological property, but of resistance to indentation. 

Gillmore needles are recommended in the relevant ISO standard, ISO 9917 (dental water-based cements) [5], with different mass needles being used for working time and setting time. The approach with these devices is to place the needle, which has a flat circular end of 1 mm radius, onto the cement for 15 s, after which the specimen is examined for any trace of a mark. If a mark is visible, the relevant time (working or setting, depending on the mass of the needle) has not been reached. 

ASTM ASfTaM. Standard test method for time of setting of hydraulic-cement paste by gillmore needles. ASTM standards. 1999 C266-99 1-3. 

The compressive strength and setting time (Gillmore needle ASTM C266-74) for several phosphate-cement concretes containing different amounts of polyphosphate in ammonium phosphate solutions are plotted in Fig. 9. At 2 hours, 24 hours, and 7 days the compressive strength increases... 

C 266 Test Method for Time of Setting of Hydraulic Cement Paste by Gillmore Needles ... 

Time of Setting by Gillmore Needles— Test Method C 266. 

Gilhnore Needle. Apparatus for the determination of the initial and final set of Portland cement (Q. A. Gillmore, Practical Treatise on Limes, Hydraulic Cements and Mortars, New York, 1864). The present form of apparatus consists of two loaded rods which slide vertically in a frame the rod ( needle ) for the determination of initial set is Vn in. (2 mm) dia. and weighs V lb (llOg), the needle for the final set is Via in. (1 mm) dia. and weighs lib (446g). Details are given in ASTM-C2 (cf. vicat needle). 

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