Waste cooking oil (WCO) is used in the Post Oil Pavement (POP) project as an alternative to bitumen in road construction to reduce environmental impact. Furthermore, a part of the project focus on cold mixes to minimize the energy expended in heating the binder and aggregates for mixing and compaction. The WCO is transformed into a binder through a maleinization reaction at 220 ℃, incorporating maleic anhydride into the WCO. The maleinized waste cooking oil (MWCO) exhibits significantly higher viscosity compared to the waste cooking oil. This MWCO can partially replace bitumen in hot, or cold mixes. The study involves the mixing of 10, 20, and 40% by weight of the MWCO with respectively 90, 80, and 60% of the 70/100 penetration grade bitumen. The mixed binder is successfully emulsified via the Atmo-agilis® colloidal mill. The emulsion, kept at 40 ℃, and 70 ℃, is subsequently examined using laser granulometry to evaluate the variation in particle size. The particle diameter measurements range from 0.1 to 1000 µm, with a prominent peak at approximately 5 µm. This approach can ascertain whether droplets remain stably suspended in the aqueous phase or progressively flocculate and ultimately coalesce, leading to the emulsion breaking. The findings demonstrate that the emulsions remain stable at 40 ℃ for more than a week; nevertheless, it destabilizes when stored at 70 ℃ after one day. This work highlights the methodology to move towards bio-sourced formulations for the road industry and address specific points of attention for building post-oil pavement.