Enhancing pavement structural resilience: analyzing the impact of vehicle-induced dynamic loads on RAP-recycled cement-stabilized crushed stone pavements with tip cracks

Most of the roads constructed in the early days have entered the phase of repair and maintenance, leading to an accumulation of large stockpiles of recycled asphalt pavement material (RAP) and posing significant challenges for environmentally sound disposal. Moreover, the low rate of reuse of RAP contributes to the excessive waste of pavement materials. This study focuses on the use of RAP in recycled cement-stabilized aggregates as the primary research subject. Proportion designs for RAP and the base course with inorganic recycled aggregates (RAI) are conducted at ratios of 1:1 (1# recycled base), 1:2 (2# recycled base), and 1:4 (3# recycled base), respectively. Subsequently, mechanical parameters are tested. Using ABAQUS software, a structural model of the reclaimed base course with cement-stabilized aggregate is created. The mechanical properties of the reclaimed base course with varying amounts of cement are analyzed under the influence of dynamic vehicle loading, taking into consideration the potential for cracking at the tip of the base course. The results indicate that under dynamic loading, the vertical stress of the recycled subgrade with 4% cement is significantly better than that of the recycled subgrade with 5% and 6% cement. Among the various recycled base cement, the 4% recycled base exhibits superior shear resistance and the lowest peak horizontal stress at the crack tip, making it less prone to cracking. In terms of vertical strain, shear strain, and horizontal strain of the recycled base layer with different cement dosages for 1# under dynamic load, the strain gradually increases as the distance between the dynamic load and the crack tip of the recycled base layer decreases, reaching the maximum value at the top of the crack tip. The sensitivity of vertical, shear, and horizontal strains at the crack tip to dynamic vehicle loading increases with the cement dosage, with larger strains occurring at a cement dosage of 6%. Therefore, while increasing the amount of cement does not effectively enhance strain at the crack tip, reasonable control of the cement amount can improve the integrity of the base course and reduce crack expansion.