Fig. 4 shows the emissions to air by the stage of the life cycle
without normalization. A trend can be observed: the
manufacturing stage was responsible for a majority of the emissions
with the disposal stage being next and the utilization stage
being last in almost every category. During the course of the life
cycle, the manufacturing stage was where all of the raw materials
and most of the energy were consumed so its majority share in the
emissions was not surprising. This is typical of this type of product
unlike buildings as a whole, where most of the emissions stem from
the utilization stage. Of the manufacturing processes modeled, the
melting and cooling/saturation processes consumed the most
electricity at about 42% of the total electricity consumption. These
observations are expected to be common to other modified asphalt