Role of a food grade additive in the high temperature performance of modified bitumens

A good adhesion between bitumen, the common binder used in the construction of pavements, and mineral aggregates is a key property for optimal performance of the road paving material (asphalt). Moreover, as bituminous material is viscoelastic in nature, an improvement of its mechanical response does represent an equally important factor in the design of roads. To date, a variety of chemical compounds has been tested as bitumen modifiers and evaluated in their capacity to improve the adhesion of binder to the aggregates and promote an increase of the bitumen softening point, especially in warm ambient conditions. This contribution explores, for the first time, the potentialities of a class of lipophilic food grade additives, i.e., non-toxic and eco-friendly biocompatible compounds, acting both as adhesion promoters and as rheological modifiers. Their effects on the high temperature mechanical performance of a tested bitumen have been investigated through time cure rheological measurements and the sol-transition temperature determined in a wide range of temperatures. Measurements of the contact angle between the aggregate surface and modified bitumens preventively blended with increasing amounts of food grade additives were also carried out. We believe that those results could provide an alternative opportunity to use additives from natural resources in the design of sustainable and much more performant asphalts.