Søgning i bogen
Den bedste måde at søge i bogen er ved at downloade PDF'en og søge i den.
Derved får du fremhævet ordene visuelt direkte på billedet af siden.
Digitaliseret bog
Bogens tekst er maskinlæst, så der kan være en del fejl og mangler.
STONE: NATURAL AND ARTIFICIAL. IO/
no case show a greater expansion than 10 millimetres after twenty-four hours’
aération and 5 millimetres after seven days’ aération.
“ The apparatus for conducting the Le Chatelier test (fig. 91) consists
of a small split cylinder of spring brass or other suitable metal of 0'5 milli-
metre (’0197 inch) in thickness, forming a mould 30 millimetres (1^ inches)
internal diameter and 30 millimetres high. On either side of the split are
attached two indicators with pointed ends AA, the distance from these ends
to the centre of the cylinder being 165 millimetres (6| inches).
“ In conducting the test, the mould is to be placed upon a small piece of
glass and filled with cement gauged in the usual way, care being taken to
Split Cylinder o.F Spring
Brass or other suitable
Metal about /a^int
thickness. y
Elevation.
Fig. 91. —Apparatus for Le Chatelier Test.
keep the edges of the mould gently together while this operation is being per-
formed. The mould is then covered with another glass plate ; a small weight
is to be placed on this, and the mould is then to be immediately placed in
water at a temperature of 58 to 64 degrees Fahrenheit and left there for
twenty-four hours.
“ The distance separating the indicator points is then to be measured, and
the mould placed in cold water, which is to be brought to boiling point in
fifteen to thirty minutes and kept boiling for six hours. After cooling, the
distance separating the points is again to be measured. The difference between
the two measurements represents the expansion of the cement, which must not
exceed the limits laid down in this spécification.”
The foregoing tests shall, as far as possible, be made within fourteen
days from full delivery of each consignment of cement, and any consign-
ment, the samples of which do not prove satisfactory in testing, shall
be rejected.
Some of the test briquettes made as described above will be kept intact
for a period of six weeks, and these will be examined from time to time.
Should auy of them show sigus of cracking or disintegration within six weeks