Use of frequency sweep and MSCR tests to characterize asphalt mastics containing ornamental stone residues and LD steel slag

This study presents an evaluation of ornamental stone industry fine by-products (OSR) and LD steel slag residue (SLR) as a potential paving material, more specifically, as filler in hot mix asphalt mixtures. In order to accomplish that, a rheological study of mastics produced by mixing an asphalt binder PG70-28 with OSR, SLR, and a mixture of both residues in different filler proportions (0.36, 0.54 and 0.72) was performed. First, the materials were characterized physically, chemically and mineralogically. Also, their microstructure was observed by image analysis using scanning electron microscopy. For the rheological parameters analysis, complex modulus (|G∗|), phase angle (δ) and multiple stress creep and recovery (MSCR) tests were carried out and compared. In general, the use of residues improved rheological behavior of the pure binder, especially SLR residue which contributed to the increase in the material stiffness since it provided greater elasticity compared to binder or OSR waste, and also showed better results of recovery and creep compliance, and reduced sensitivity to tension.