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To resolve how granular aggregates fragment and reaccumulate during low-speed planetary encounters, this work formulates a bonded-particle discrete-element model coupling short-range contact dissipation, irreversible bond rupture, and all-pairs Newtonian self-gravity. Accurately modeling this competition between micro-scale cohesion and macro-scale gravity is essential for predicting the structural fate and mass evolution of rubble-pile asteroids. Across 125 simulated low-speed collisions initiated from mutual gravitational attraction, 56.8% of encounters resulted in a single merged residue, establishing precise cohesion-scaling regimes from structural preservation ($\Pi_\sigma \lesssim 0.036$) to total disruption ($\Pi_\sigma \approx 3.59$).
Low-speed gravitational collisions yield a single reaccumulated body nearly 57% of the time, bounded by a sharp dimensionless cohesion threshold that dictates whether granular bonds remain entirely intact or catastrophically fail.
I present a discrete-element approach developed to study the collisional and gravitational evolution of small self-gravitating granular aggregates. Each body is represented as a composite of cohesively bonded spherical grains, so that fragmentation and reaccumulation emerge from the microscopic competition between short-range dissipative contact forces, an irreversible bond-breaking criterion, and pairwise Newtonian self-gravity summed over every particle pair, including those internal to a single body. A numerical experiment is described: a random-sequential packing procedure that generates two bonded spherical aggregates, a controlled two-body encounter with tunable approach speed and impact parameter, and a systematic parameter sweep designed to map the conditions under which two bodies launched from rest under their mutual gravity alone either merge into a single remnant or fail to settle after a low-speed encounter. Of the 125 simulated collisions, 56.8\% result in the formation of a single residue. The cohesive network remains intact for $\Pi_\sigma\lesssim0.036$, is partially damaged with dispersion determined by the contact damping ratio, and breaks completely for $\Pi_\sigma\approx3.59$