Adhesive

Adhesion

Metallurgy

Materials science

Layer (electronics)

Slag (welding)

Aggregate (composite)

Asphalt concrete

Asphalt

Composite material

Construction and Building Materials

Steel slag, as an industrial waste, is a potential alternative to replace aggregate in asphalt mixture, but the interaction mechanism between asphalt and steel slag is still not understood. In this study, asphalt-steel slag interfacial model was established to carry out molecular dynamics simulation to measure the interaction of the two materials. The radial distribution function and relative concentration were defined to illustrate the aggregations of asphalt components on steel slag under both dry and humid conditions. And the weakly alkaline and acidic minerals were also used as controls. The results show resin in asphalt is more likely to gather around weakly alkaline (limestone) and strongly alkaline (steel slag) minerals while the opposite is true for acid minerals (granite). For acidic and weakly alkaline minerals, Van der Waals effect accounts for most of the adhesion while for strongly alkaline minerals, Coulomb interaction dominates. Steel slag has the highest adhesive capacity, following by limestone and granite under both dry and humid conditions. The interfacial strength of asphalt and minerals is tightly relevant to the chemical compositions of both aggregate and asphalt. The interaction mechanisms of steel slag and asphalt at the molecular level help evaluating steel slag and selecting suitable asphalt in field application.

Molecular dynamics simulation of distribution and adhesion of asphalt components on steel slag