FINITE ELEMENT PERFORMANCE EVALUATION OF ASPHALTCONCRETE PAVEMENTS WITH BASIC OXYGEN FURNACE SLAGAS A COARSE AGGREGATE REPLACEMENT

Аннотация

The use of steelmaking by-products in road construction reduces the demand for virgin aggregate and supports circular economy practices in the road sector. This paper evaluates the structural performance of an asphalt concrete pavement in which the coarse aggregate of the wearing course is replaced with Basic Oxygen Furnace (BOF) slag. A four-layer flexible pavement was modelled in ABAQUS 2021 under both linear elastic and linear viscoelastic constitutive laws, the latter through a four-term Prony series with a Williams-Landel-Ferry shift function fitted to laboratory data, and was validated against published benchmark results with a deviation of 1.32 % in maximum rutting depth. A conventional pavement with a fine-grained gravel wearing course (E = 3340 MPa at 20 °C) was compared with a BOF slag-modified pavement (E = 2135 MPa at 20 °C). The rutting depths were 2.49 mm and 2.58 mm under the elastic assumption (3.6 %) and 2.42 mm and 2.53 mm under the viscoelastic assumption (4.5 %), while the peak von Mises stress was lower in the BOF slag pavement in both cases (1.31 MPa against 1.48 MPa and 1.41 MPa against 1.59 MPa). The sensitivity of the structure to the surface layer is expressed as a power law: the rutting depth scales with the wearing course modulus to the power of -0.08 under the elastic and -0.10 under the viscoelastic assumption and the peak stress to the power of +0.27, so that a reduction of the surface stiffness by 36 % changes the structural response by less than 5 %. At the scale of a two-lane carriageway the substitution replaces about 800 t of natural crushed stone per kilometre of wearing course. BOF slag can therefore be regarded as a technically viable and sustainable aggregate substitute for wearing course mixtures, provided that the volumetric stability of the slag is verified before placement.