Evaluation of a B3-Bond stabilized blast furnace slag (B3-Bond) modified MDC-25 asphalt mix and its effect on mechanical strength under monotonic loading.

Abstract

The excessive consumption of non-renewable natural resources, the effects of climate change and the changing environmental regulations make it necessary to evaluate the possibility of using alternative materials with recycling potential, without polluting effects, and whose characteristics allow its use within the construction processes of a roadwork. Several researchers have concluded that by substituting part of the aggregates of an asphalt mix with slag from the iron production process, the physical, chemical and mechanical properties of the mix can be enhanced. The present study evaluated the mechanical response under monotonic loading of an asphalt mix type MDC-25 modified with blast furnace slag (EAH), stabilized with a polymeric liquid additive called B3-Bond. Once the raw materials (60/70 asphalt cement, stone aggregates, slag in its original state, stabilized slag, B3-Bond additive) were characterized, a dosage plan was designed based on the percentages of asphalt and the proportion of slag that would replace the granular material in a reference asphalt mix for certain sieves. From the results, it was concluded that the MDC-25 asphalt mix added with slag (with and without stabilization), with asphalt contents of 5.0, 5.3 and 5.5%, had a higher Marshall stiffness than the control mix. In relation to the results of the indirect tensile test, it was concluded that the higher the asphalt content, the higher the resistance, both in dry and submerged conditions. This is due to the fact that the aggregates have a better coating and, therefore, the adherence between them increases. In addition, when the slag is stabilized with the B3- Bond additive, it is not necessary to increase the asphalt content to have a better or equal resistance to indirect traction with respect to the control mix.