Rheological Analysis: A Powerful Tool for the Characterization of Bituminous Compounds in the Production of Waterproofing Membranes

The compatibility between bitumen and polymers is a critical factor that significantly influences the mechanical and rheological properties of bituminous compounds. Poor compatibility with polymers can lead to challenges in the formulation of bituminous blends. Industrial-grade bitumen is typically produced in specialized facilities using tailored processes. Careful selection of crude sources ensures optimal characteristics for formulating compounds used in the production of waterproofing membranes. Polyolefins and elastomers are commonly employed in these applications due to their superior compatibility with bitumen. Conversely, road bitumen is extensively utilized in the construction and maintenance of flexible, high-performance pavements. It typically exhibits a lower penetration grade and greater market availability. This study aims to evaluate the feasibility of employing road bitumen in the production of bituminous membranes by comparing its performance with that of polymer-modified bitumen through rheological and mechanical testing. A comprehensive rheological characterization was conducted on the bituminous compounds. Samples were analyzed using a strain-controlled rheometer with a “temperature sweep” protocol—an oscillatory test wherein both the elastic (G′) and viscous (G″) moduli were measured as the sample was cooled at a fixed frequency within the viscoelastic range. This analysis provides valuable insights into the temperature-dependent behavior of the bituminous compounds. Additionally, a dynamic mechanical analyzer (DMA) was employed to assess viscoelastic properties under simulated application conditions, such as varying climatic environments.