Microstructure Analysis of Cold Bituminous Emulsion Mixture Using Different Filler Type

In today's scenario, the environmental impact of the transport sector plays a major role in net carbon emission generation and global warming. Seeing the emerging environmental issue, it has been mandatory to adopt sustainable technologies in every sector. The use of bitumen emulsion in the construction of pavement has been rapidly enhanced in the last decade. This technology eliminates the heating of aggregate and binder, resulting in a reduction of greenhouse gas emissions and energy consumption, which is also termed as cold mix technology. Filler has a major role in the formation of bonds between bitumen emulsion and aggregate. In the present study, cement, lime, and fly ash have been considered as filler materials along with stone dust and the required optimum emulsion content and water content were determined. The impact of filler on the breaking of bitumen emulsion is studied through scanning electron microscope image analysis. The impact of filler on pH of bitumen emulsion mastic is also evaluated. The optimum emulsion content in cold bituminous emulsion mixtures (CBEMs) depends on the particle size of the filler. The required water content for lime is less compared to other filler materials. The results show that cement and fly ash are pozzolanic in nature, form hydration products in the presence of water in CBEM, and result in higher density and stability. The study depicts the role of filler material in CBEM at the microlevel.