The South African Roads Industry is aware of the success achieved with bitumen
rubber over the last 25 years. Due to its visco-elastic behaviour, the binder requires
elevated temperatures to handle the product in sprayed seal and asphalt applications. The
experience by the roads industry of the rapid deterioration of bitumen rubber when handled
at high temperatures during sprayed seal applications created perceptions regarding the use
of bitumen rubber in asphalt applications. One of the perceived drawbacks of bitumen
rubber in asphalt application is its limited shelf-life. While investigating flushing problems
during the construction of the bitumen rubber asphalt semi open (BRASO), it was implicated
that these problems may have been as a result of binder degradation associated with the
limited shelf-life of the binder at high temperatures. The bitumen rubber suppliers and
asphalt manufacturers were requested to conduct shelf-life studies to duplicate the bitumen
rubber binder’s time-temperature profiles at various scales of operation. The shelf-life
studies included laboratory blends with two different grades of base binder and static and
dynamic storage tests. The laboratory study was also repeated on a large scale,
manufacturing bitumen rubber through a sprayer unit. The properties of the product were
monitored over a twelve hour period and the asphalt properties of the aged binder at
different stages of ageing were tested to assess the impact of binder ageing on the BRASO
behaviour. These studies revealed important facts that are often misunderstood. In this
paper, the misperceptions of bitumen rubber shelf-life are addressed and the effect of the
base binder, the scale of operations and the storage stability will be contextualised
indicating a much improved actual shelf-life in asphalt cement relative to the current 4-6
hours allowed.