The influence of processed steel slag on the performance of a bituminous mixture

Resumo

The use of recycled materials in pavements gains a wider acceptance for a more
sustainable construction and rehabilitation of the transport infrastructures. An example is the
incorporation of steel slag in bituminous mixtures. This paper refers to the evaluation of
fatigue properties for a bituminous mixture – AC 20 base 35/50 – that include processed steel
slag aggregate (SSA) in their composition. Two types of this bituminous mixture were
considered: a hot asphalt mixture, incorporating 20% of SSA, and a warm asphalt mixture,
with the additive Sasobit and incorporating 30 % of SSA. To compare the performance of
SSA bituminous mixtures to the equivalent traditional bituminous mixture, materials were
evaluated in the laboratory by fatigue tests. Repeated flexural loading on the four-point
bending beam apparatus was conducted on samples to compare how the SSA affects fatigue
cracking. Laboratory tests were performed according to the standard EN 12697-24. Test
results are presented and they indicated, in general, that the incorporation of SSA has not
impaired the fatigue behavior of the bituminous mixture. This preliminary conclusion, to be
confirmed in further research, suggests that the application in pavement layers of the SSA
bituminous mixture considered in this study is still possible in terms of road bearing capacity,
beyond the benefit of promoting the recycle of an industrial waste.