Characterising the influence of bitumen emulsion on asphalt mixture performance: Fid-Bau Portal

Characterising the influence of bitumen emulsion on asphalt mixture performance

Miljković, Miomir

To make the road infrastructure more competitive and sustainable, a long-term transition to cold asphalt technologies, especially those which involve bitumen emulsions is necessary. However, to minimise the compromise on mechanical performance compared to the conventional technologies, the objective of this research was to propose a comprehensive method for evaluating the contribution of the bitumen emulsion to the asphalt mixture properties. The variable influence of the aggregate was eliminated by standardising the aggregate composition of bitumen emulsion mortar (BEM), and the BEM mixtures were tested with various emulsion-related parameters. The change in physical and indirect tensile test-based mechanical properties was measured over time on statically-compacted cylindrical specimens in pre-defined curing conditions. Almost the entire change in physical and volumetric properties occurred in the first 28 days of curing. As a rule, the mixtures with higher emulsion content were more sensitive to the bitumen viscosity, and the harder bitumens resulted in higher indirect tensile strengths. The measured change in the bulk densities and the voids over time was compared with calculated theoretical values to which the lowest emulsion contents had the fastest convergence. Furthermore, coefficients for estimating the mechanical parameters based on the 28 day-reference values were determined, and the standard BEM mixture composition was adopted. Finally, this evaluation approach showed a good potential of becoming a standard method for testing and improving the bitumen emulsion properties.