The analysis of the physical and chemical properties of the mixture of calcite and residual toner powder
was performed by the Department of Public Health, Dr. Andrija Štampar, Zagreb, Croatia, in accordance
with the prerequisites of the HRN ENISO/IEC 17025 standard (2013).
On an industrial scale, the mixture of residual toner and calcite has been tested as a partial substitute for
conventional fillers. About 35 % of pure calcite usually added to a single batch of joint sealant has been
replaced with calcite contained in the added residual toner mixture. Due to a lack of knowledge about the
exact composition of the residual toner, i.e. its polymer content, the quantity of virgin polymer filler needed
to be left intact, in order to assure the product's compliance with EN 14188-1. The total amount of toner
mixture added to one batch of joint sealant was 160 kg (~ 10 %).
One of the standard specification tests for bitumens and bituminous products is the determination of their
softening point, which is defined as the temperature at which the tested substance, under specified
conditions, attains a particular degree of softening. The softening point is useful in the classification of
bitumens into different grades, and in this investigation it has been tested according to the European
Standard EN 1427, that is, with the help of the Ring and Ball apparatus.