8.3 Loss on Ignition:
8.3.1 Portland Cement—Immediately before and after the
calorimetric sample is being weighed out, weigh a sample of
similar amount into a platinum crucible for determination of
loss on ignition, the value to be used being the average of the
two determinations. Ignite the dry cement at 950 6 50°C for at
least 11⁄2 h or to constant mass. Immediately place the crucible
containing the sample in a desiccator and allow to cool to room
temperature; then quickly weigh the crucible. When determining
the loss on ignition of the hydrated cement, first dry the
weighed sample in an oven at 100 to 110°C for 1 h; then place
the sample in a muffle furnace at 950 6 50°C overnight, or
bring to constant mass. Reduce the mass of the cement sample
that was introduced into the calorimeter to the ignited mass
basis for use in the final calculations as follows: