Fracture behaviour of bitumen emulsion mortar mixtures

• The bitumen emulsion mortar specimen ductility reaches the maximum after approximately 28 days.
• Three months after the compaction, fracture of all the specimens was clearly brittle.
• The evaluated energy-based parameters were substantially dependent on the viscosity of the bitumen in the emulsions.
• The adhesion between the binder and the aggregate was assumed to emerge faster than the binder’s viscosity increased.

The research objective was to evaluate the fracture behaviour of the bitumen emulsion mortar (BEM) mixtures, in terms of their ductility/brittleness, by considering the fracture work and the deformation energy parameters. The specimens with different bitumen emulsions and contents were subjected to the indirect tensile test after 7, 28, and 84 days of curing. The results showed an increase in the specific fracture work over time, while the deformation energy first significantly increased and then decreased to a relatively low level. The deformation energy to total deformation energy-ratio was identified as the most suitable to characterise the fracture behaviour, The adhesion between the binder and the sand in the localised contact regions was assumed to be established faster, which enabled the specimen ductility in the first weeks of curing, while the final binder viscosity achieved by the water evaporation influenced the clearly brittle fracture after three months.