535
Yastam Works,
of the proper way in which to test Portland Cement
27. (a) When ground the Cement is sampled, and weighed, by myself or my Staff - Samples are taken from various parts of the heap so as to get an average of the whole - These samples are then weighed in Imperial bushel measure of special diameter and depth - The cement is fed into the measure by means of a specially constructed hopper with an annular outlet allowing only a definite quantity to pass through in a given time. This outlet is exactly 18″ above the top of the measure - The cement is shaken slowly into the hopper - when full the measure is struck and weighed - Great care must be taken not to touch or shake the measure or hopper while the process continues - If the average of the weighings be 1/2 lbs or over the cement is accepted for weight.
(b) Samples are then brought to my testing rooms here - known weights of cement are sifted in special sieves of 1600 meshes to the square inch - The residue is weighed and the average of the several siftings taken. If the residue be not more than 10% of the total weight of the Cement it passes for fineness.
(c.) Buru-
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