Sustainable application of recycled waste paper as a cellulose-containing additive in stone mastic asphalt

Stone mastic asphalt (SMA) is widely used in road construction for its durability and deformation resistance; however, its high binder content makes it prone to drain-down during production and placement. To address this limitation, various stabilizing fibers are employed, though most are synthetic and environmentally unsustainable. This study investigates a cellulose-containing additive (CCA) derived from recycled waste paper as a renewable stabilizer for SMA, aiming to minimize binder drain-down while maintaining mechanical performance. The recycled cellulose was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis, confirming structural integrity and thermal stability suitable for asphalt mixing. SMA mixtures containing 0.4–0.8 wt% CCA were prepared and compared with a commercial stabilizer. The recycled additive effectively reduced binder drain-down from 0.16 % to 0.05 %, remaining below the 0.20 % limit. At 0.6 % dosage, compressive and tensile strengths were comparable to those of the commercial stabilizer, while rutting resistance and moisture durability improved. Scanning electron microscopy revealed uniform fiber dispersion and a stable micro-network at this optimum dosage. The results demonstrate that recycled paper-derived cellulose can successfully replace conventional stabilizers, offering comparable performance with lower environmental impact and supporting circular-economy practices in pavement engineering. • Recycled paper waste was utilized as a cellulose-based additive in stone mastic asphalt. • A cellulose- based additive dosage between 0.4–0.8 % reduced bitumen draindown and improved rutting resistance. • Optimal dosage of about 0.6 % balanced strength, durability, and moisture resistance. • SEM and TGA analyses confirmed thermal stability and reinforcing micro-network formation.