Enhancing shear resistance in pavement structures with crumb rubber modified asphalt gravel as a bonding layer

This paper introduces a groundbreaking approach to enhance shear resistance in pavement structures through the utilization of crumb rubber modified asphalt gravel as an innovative bonding layer. The study addresses the challenge of interlaminar shear failure in semi-rigid base asphalt pavement by conducting 48 shear experiments with 144 samples. The optimization process involves varying parameters such as rubber powder mesh size, modified asphalt application amount, gravel particle size, and gravel application amount. ANOVA results underscore the significance of these factors, with gravel particle size, application rate, and rubber powder modified asphalt rate playing crucial roles. The optimal bonding layer configuration is identified as 40 mesh rubber powder, 0.9 L/m2 dosage, 80% gravel, and 5–10 mm gravel particle size. Comparative analysis demonstrates the superior shear strength of the rubber powder modified asphalt gravel bonding layer, achieving nearly twice the strength of base asphalt and three times that of emulsified asphalt. Numerical analysis affirms its robust performance under extreme driving loads, providing a maximum shear stress of 0.0826 MPa even at 100% overload, while the bonding layer can offer 1.148 MPa. Evaluation across low, medium, and high service temperatures reveals consistent superiority over traditional bonding materials. The study emphasizes the sustainable nature of this innovation, utilizing recycled scrap tires, reducing carbon emissions, and offering environmental and economic benefits. In conclusion, rubber powder-modified asphalt macadam bonding layers emerge as a promising solution for enhancing shear performance in pavement structures.